Dahua DH-SD22204T Security Camera

I recently decided to install an outdoor PTZ security camera at our beach house to keep an eye on the premises, not to mention the threatening tide line during storms. After installing a “Sumpple WiFi Wireless PTZ” outdoors, it lasted about two weeks before becoming completely non-responsive. Total Crap.

For my second try, I ordered a Dahua SD22204T-GN, which is actually about $15 cheaper, supports PoE, but doesn’t have WiFi. This is fine with me (actually preferable) in this case – it turned out the WiFi signal was so weak where I want to mount the camera, I had to run 10BaseT to it anyway. PoE gives me a more convenient way to run power to it and replace the power supply, if it goes out. This time I paid an extra $5 for the insurance, so if it dies, it’s going straight back for a full refund and I’ll move on to another one ūüôā

So far, this seems like a very good camera for the price. I have not installed it outdoors yet, but checking it out on my desk, it seems solid. The image quality is quite good, even at night. Although the camera has no IR LED’s, the light sensitivity is very good and I get a good image with only a small amount of ambient lighting. The web interface is robust, although live video doesn’t display natively in Google Chrome – you will have to install the “NACL” plugin. Also, although the camera does support built-in motion detection, it doesn’t have a nice feature that the Sumpple had to run a remote (ssh) command, which let me send a text via Twilio from my home server. It does support typical options to record to SD card, FTP a captured recording, or email. The email option works for me, since I can email my phone’s SMS address, but is a little annoying because it sends three¬† event emails;¬†“Start”, “Recording” and “End”. I wound up setting up a “go-between” email account with a filter to only forward the “Recording” event to my phone. This onb of the three also includes a thumbnail (although occasionally the thumbnail is not present for some reason).

To install an SD card or mount the camera to a surface, you will need a T10 torx bit, as the enclosure is fastened with “tamper-proof” torx screws and the surface mount holes and SD slot are internal – not necessarily a bad thing.

Some useful information for anyone trying to use the camera with ContaCam:
I wanted to use the camera with ContaCam and it took some trial and error to get a connection to work. I finally used the following connection string with my user credentials in the “Camera login” section:
Use subtype 0 for the main stream or 1 for the secondary stream.

A more “generic” url that works with VLC is:

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ESP8266 with ILI9341/XPT2046 TFT Display w/ touch

These 2.8″ 240×320 pixel color TFT displays for $8-10 ¬†can be found on ALiExpress. There’s also an equivalent-looking one offered by AdaFruit for $30 if you want one fast – the pins are quite differently label, but I’m willing to be it’s virtually equivalent. I just LOVE AliExpress – stuff is SO CHEAP! But, as is usually the case, the Adafruit one is well-document..the Chinese version, not so much. There are a smattering of posts and github libraries out there, but none document very clearly exactly how to hook one of these up, so I will describe here how I got one working.

I first spent a bunch of time trying to get¬†one of the libraries that was coming up a lot for the XPT2046 touch functionality to work. That XPT2046 library seems to be the “standard” out there, but there’s no clear documentation of the hookup and it uses a somewhat cumbersome library for the TFT display.

The key that finally got me going was¬†this blog post¬†– it was one of the most useful, since it has a good hookup diagram, which I’ll include here, in case the post goes away. That post also refers to the XPT2046 library¬†for touch input, but uses the AdaFruit TFT Driver¬†and even includes a zip file containing the AdaFruit driver and examples comprised of versions of the XPTCalibrate and XPTPaint sketchs modified to use the AdaFruit display library. With those samples and¬†the help of the hookup diagram, I was able to get things working. The diagram is a big help, since the pin labels on the cheap Chinese board don’t really match what is referred to in sample sketches. Also, it isn’t completely intuitive that you need to connect the SPI pins (SCK, CS, MOSI & MISO) to the standard pins for those signals on the ESP8266. I include the diagram here, in case that post goes away.

Once I got the pin hookup figured out, I was also able to get the sketches included with the XPT2046 library working – they use a display driver (which you also have to install) authored by the same developer, but I wound up using the AdaFruit driver for the ILI9341 TFT. It is based on AdaFruit_GFX and offers a lot more functionality, including a conventient button-drawing-press-detection framework.

Overall, this is another one of those components that just blows me away for being so cheap (especially when you buy it from China), but giving you such impressive functionality. In my next post, I’ll outline how I incorporate this into a wrist-controller form my LightSuit Version 3.


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ESP-01 V3 Doesn’t Reset or Run

I recently ordered a set of 10 new ESP-01’s from China.¬† After the usual few weeks, they arrived. I pulled one out, plugged it into the socket on my little interface board – which has buttons for RST and GPIO0, a 3.3V regulator, and pins to hook my USB-to-TTL cable to. That little board makes it really easy to program these minimal-feature ESP8266 boards.

So, I go through my process of setting the board options in the Arduino IDE, clicking “Program”, and then holding down the GPIO0 button, while momentarily pressing RST. I immediately noticed that I didn’t see the usual short flash of the LED (which is connect to the TX pin on ESP-01 boards). It then failed to write to flash. After some experimenting, I could get it to write to flash by holding GPIO0 down while plugging the USB cable in. However, my sketch didn’t seem to execute. I hit RST again and nothing happened. Reset was definitely not doing anything, and no matter what I did, I couldn’t get my sketch to run (I knew it worked, because I could flash it to an older ESP-01 and it ran fine).

So finally, after googling abit, I discovered that people are sometimes now receiving “V3” versions of the ESP-01. This seems to vary a bit between different vendors – some still ship V2’s, some send V3’s. And the difference on the V3 is that there is now a 6K resistor inline with the pin on the ESP-01 and the RST pin on the actual chip. This seems to prevent RST from working and prevents the chip from entering run mode on power-up. The post I found included the following picture illustrating where the resistor is. With some relatively fine soldering skills, you can remove the resistor and solder a fine jumper wire in place, which solves the problem. DON’T FORGET that you also have to pull CH_PD HIGH for the chip to enter run mode – I usually solder another jumper directly onto the ESP-01 to do this, except in cases where I what to have control over the chip entering low-power mode.

This is also documented on the ESP-10 wiki here: https://www.letscontrolit.com/wiki/index.php/ESP-01#ESP-01_v3




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Wine Fridge Temperature Controller – V2

In a previous post, I described how I replaced the highly-proprietary power supply on min wine refrigerator with an off-the-shelf supply and a Monster Moto shield to drive the fans and termoelectric peltier heat sinks based on the PWM (pulse-width modulated) signal from the controller head unit.

Recently,¬† I noticed the actually temperature was no longer tracking to the set temperature. Then, a couple months after that the supply completely died again. I guess the temp being off was a symptom of it dying. In any case, it was time to look at replacing it again. Last time, I was never completely happy with the klugey way I massaged the PWM signal to drive the cooling components – it never really got to where the PWM duty cycle was ON a high percentage, so it didn’t cool fast or to low temperatures. I knew what I really needed to do was put a smarter controller on the Moto shield (like a real Arduino) so that I would have full software control over the PWM driving signal. The Monstor Moto shield is intended for an Arduino in any case.

This time around, I decided to do that. This would mean effectively replacing the “head unit” too, since it had a small embedded processor that was responsible for taking input from the temp up/down buttons, the temp sensor (an NTC thermistor, I believe), driving the LED temperature display, and producing the PWM signal that controlled the original power supply output power. Rather than try to cut up the head-unit circuit board, re-route the buttons to the Arduino, and figure out how to drive the 2 8-segment LED temp display, which would require additional circuitry or some kind of display driver board, I decided to use an ESP8266 board with an OLED display in the front-end. This had the added advantages of giving me full software control over cooler operation and making it¬† very easy to WiFi-enable my fridge ūüôā

I bought a different, higher amperage, power supply to cannibalize – I figure that will help keep it from burning out. It also has an integrated fan, which I’ll drive off the same PWM-moderated output voltage.

12V 15A AC to DC Power Supply

12V 15A AC to DC Power Supply

This is a link to what I bought –¬†Home Usage AC-DC 12V 15A 180W Adapter Converter with Car Cigarette Lighter Socket.¬†In case the link dies, it looks like this:

Turns out the fan was quite loud, so I also bought an “ultra quite” 12V 50mmx50mm fan off of eBay.

I found an ESP8266 board which had an on-board 32×90 pixel OLED display:¬†The Heltec “WiFi Kit 8”

I added an Arduino, which actually drives the Moto Shield now. It also reads the temperature sensor. Based on the temperature reading, it adjusts the PWM duty cycle to be more or less aggressive about cooling, based on the difference between the “target” temperature and the measured “current” temperature.

Determining the temperature wound up being more complicated than I hoped. At first, I tried a little Arduino routine I found on the Arduino Playground for deriving temperature from an Thermistor connected to an Analog Input pin, but it was giving me values that were way out of whack…not sure why. I probably could have integrated a digital temp sensor, like the DHT11 or TMP102’s that I’ve used before, but I wanted to use the existing wiring that goes between the internal “head unit”, penetrates the enclosure, and ends where the power control circuitry is, which limits how many conductors I can use.

The internal temp sensor already had the wiring in place, and was nicely positioned in the air-stream of one of the internal fans. I wound up putting a TMP102-based ESP8266-connected sensor I use to monitor my bedroom temperature (for home automation purposes) inside the fridge, and wired the temp sensor to the Arduino A0 pin using the circuit from the Arduino Playground page. I then wrote a test sketch that drove the Moto shield and cooling hardware at constant duty cycles and logged the analog reading of the sensor connected to the serial port. I was then able to create a graph in Excel that correlated actual temperature to Analog reading:Capture

As you can see, this produced a very predictable and linear trend line. From that I was able to write a very simple routine derived from the the starting point of a reading on 830 (60¬į) and the slope of the line – see my Thermistor() function in WineCoolerDriver.ino. I also average multiple analog readings together before calling the function function, since the analog inputs can be a bit “noisy”. I also average ten temperature readings over time and base the PWM duty cycle on this moving average to reduce “jitter” in the “current” temperature and the duty cycle driving the cooling hardware.

I use the ESP8266 board to display the current temp and target “set_point” temperature. It also provides a WiFi interface for setting the target temp and ready the current temp values. I connected the ESP8266 to the Arduino over two of the available conductors over a “serial2” port using the SoftwareSerial library (leaving the Serial port on both boards available for debugging and¬† diagnostics). The ESP8266 periodically sends a one-byte target temperature setting to the Arduino, and the Arduino periodically sends the current temp to the ESP8266 for update of the display.

Here’s a Fritzing diagram of the Arduino, Moto, ESP8266 and sensor. See the last post which shows connections to fan/peltier assemblies.Fritzing

I actually added a couple of buttons (not depicted) (GPIO13 & 14) on the ESP for direct temp control.

Here’s the Moto Shield and Arduino assembly:¬†IMG_20180204_100325742

Note that I stuck some stick-on heat sinks on either side of the VNH2SP30 chips,a s they seemed to get pretty hot under full load. That necessitated adding some extra risers between the shield and Arduino for clearance.

Here’s the Assembled “front-end”:¬†IMG_20180209_080934852.jpg

I expanded the little window to accommodate the wider OLED and just cut a hole for the LED push-on/push-off button.


I also glued a couple of push-buttons in place behind the temperature up/down blisters (they are embedded in the white glue) and I used some Polymorph thermoplastic to form a sort of “bracket” that holds the board in place without being permanently attached. I highly recommend checking out thermoplastic – it is super versatile. You just heat it in boiling (well, not even boiling…) water. It softens at 150 degrees, at which point it’s like putty, then it hardens to normal plastic hardness when it cools.

Here it is fully operational:IMG_20180211_121133237





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Wine Cooler Power Supply

I’m just going to blog about this one briefly, in case their are any other enterprising Wine Cooler owners out there who find that, two years into owning their cheapo wine cooler, the power supply craps out. I didn’t take pics all the way through, so it won’t be much of a step-by-step build log.

A couple years ago I bought a “AZ-EA45EC-75” on Amazon. If you read reviews for these wine coolers, you WILL notice that there are more complaints about the cheaper ones breaking down after a year or two (often out of warranty). But I figured the price differential was worth it, especially if I got one ¬†that is cooled via Peltier thermocouples, since I’d have a chance at repairing it if something went out.

Sure enough, a few months ago, the power supply went out. I can troubleshoot basic electronics, but troubleshooting a switching power supple (which this thing had) is a bit beyond me. I did try replacing some darlington transistors that showed a lot of heat discoloration on the circuit board, thinking they might have burned out (one was not very well secured to the large heat sink). No go. Maybe there was a cascade failure or something…i think maybe the winding on one of the very specialized transformers was also out. I even succeeded in tracking down the Chinese manufacturer of the power supply (the website was printed on it), and emailed them to see if I could just buy one unit. After a couple tries, I actually got a response (in bad english) that I think said I could send it to them and they would repair it for, like $80, and send it back..with me paying shipping both ways. No thanks.

In pulling the thing apart, I learned that the cooling system consists of the switching power supply, two thermocouples – each with an outside and an inside fan which look like typical PC power supply fans – some kind of internal temp sensor, and a little control board that includes the temp control buttons and current temp readout. Oh, and a little LED light array inside that you can turn on and off with a button on the control panel. They all connect to the power supply. The thermocouples and fans are just 12V powered, but clearly there is some logic somewhere to throttle how much power goes to them, since it would work harder when trying to cool down, but bee nearly silent when the internal temperature matched what you set the controller to.

The controller board had a 5 pin connector, and it was actually labeled: 12V, Gnd, LED, NTC, and PWM. I guessed (correctly) that LED controlled power to the light – I think it was just wired straight though on the power supply, since 5V regulated came out on that pin, and the LED array required 5V to light up. PWM was interesting – my guess (again, correctly) was that they Pulse Width Modulated the power to the two sets of thermocouples and fans. To verify this, I finally broke down (after 30+ years!) and bought ¬†an inexpensive USB-based oscilloscope. I bought a Sain Smart DDS-120 for about 150 bucks and it was totally adequate for my needs…and now I finally have at least a cheap o-scope!

Anyway, using the o-scope, I verified that there was a 5V square wave coming out of the PWM in. Actually, ¬†first I had to figure out what “NTC” was. Initially, providing 12V to the controller made the LED readout light up fine (and the LED button controlled whether 5V came out on that pin or not), but the readout would flash a few times, then show “E1”. I though on it a while and figured maybe it needed to sense a temperature to work. Turns out, it’s common to sense temperature with is an “NTC” ¬†thermister¬†ūüôā I wired a resistor in the 10K range across the NTC pin and Gnd and – sure enough – the readout would show 59¬į. When I turned the temp down below 59, the “off” period of the PWM square wave was¬†longer – when I set the temp over 59, the “off” period got shorter. So, the “off” time of the PWM theoretically drives the power to the thermocouple clusters…kind of an inverse relationship..not a big deal, since I could easily invert that signal if necessary.

I started casting about for an easy way to drive a fair amount of power via the 5V logic signal from the PWM pin – from¬†googling around, I estimated that driving a thermocouple and a couple of fans at full power could eat an amp or more. I prefer to find pre-assembled boards for more complicated circuits, since assembling a lot of discrete components can be pretty error-prone, plus I’m just not that great at linear circuit design. After looking around a while, I decided on the Monster Moto Shield. Intended to drive robot motors, this sucker can sink a lot of current. As the name implies, it’s intended to be used with an Arduino, but I just hard-wired the control pins to the appropriate logic level and tied the PWM pins to the PWM out from the fridge controller (after going through a couple of inverter components, described below).

I should say, in between all this – which took place over a week or two – I temporarily rigged up one thermocouple/fan set to just run continuously off a 12V laptop power supply I had lying around. This actually worked pretty well. Since I was just running one, it seemed to keep the cooler chilled, but not too cold. I even considered making it more permanent, and just buttoning it up and blowing off temp control, but that would have been to easy ūüôā

Here’s a rough Fritzing diagram of the whole rig.WineFridgeFritzing_bb

I used a simple NPN transistor, to invert the signal coming from the controller board, tying the PWM inputs of the two Monster Moto channels to the “high side” (collector) of the transistor. So, when the signal coming out of the controller is low, the driver side is high and visa versa.

Update (4/28/16): As I tried this rig out hooked up, I discovered that it had trouble getting the temp below about 58¬į. This seemed to be due to the fact the the PWM duty¬†never really got above more than about 60%. I added a low-side resistor on the transistor emitter to bias the output higher, then a diode and a capacitor which effectively “store” some of the “on” energy, while the diode prevents leakage backwards. This smoothed out the output, but also biased it slightly higher, resulting in more time above the Moto shield’s PWM trigger level. I basically picked the values by just experimenting – in fact, I’m not even positive of the cap value – I just found one in my tray of caps that was in-between doing almost nothing and causing the PWM signal to basically be always-on.¬†

I bought a cheap 12V switching power supply capable of delivering multiple amps from China. Here’s a picture of the whole thing rigged together temporarily. It looks like a rats nest, but will look a lot better when I consolidate all this into just the power supply, Moto shield, and a little daughter board.ratsnest

The Moto shield gets pretty hot when it’s really cooling, so I stuck a couple of little heat sinks I had to the two¬†VNH2SP30’s, and even they seemed inadequate, hence the extra aluminum foil ūüôā For a more permanent solution, I’ve order a half dozen 20mm x 20mm heat sinks from Amazon that should arrive in a couple of days.

Total cost for all this – about $50. That’s not included the O-Scope, but¬†everone deserves an o-scope! And of course, time…I spent a lot of that reverse engineering and tinkering with getting the input¬†levels right on the Moto pins. Definitely a cheap fix, PLUS now I have something that’s much more maintainable, since I basically put the whole power circuit together myself.

Update (1/25/2018): Well, my cheapo Chinese power supply burned out – these things really don’t last well! I think part of the problem may be poor ventilation around the supply. Anyway, I bought one of these:¬†https://www.amazon.com/gp/product/B01ET14J8O¬†for about $35. It has an integrated fan, which I hope will keep it cooler and help with lifespan. I intend to remove the case and just mount the guts to the wine cooler. The fan is actually kind of loud, so I may also order a quieter 50mm 12v fan. I also wasn’t very happy with the above circuit to drive the Moto shield from the PWM signal – it was never getting below about 57 degrees – I guess because the square wave didn’t have enough “on” time. So I’m just going to replace the control circuitry entirely with an Arduino. While I’m at it, I’m going to wire in an ESP8266 with an OLED screen to display the temp and let me monitor and set it via WiFi. It’s not lost on me that, at that point, aside from the thermocouple-and-fan assemblies, I’ll have practically built a wine cooler from scratch :-/¬† Actually…maybe there’s a business in custom wine-fridges… Anyway, I’ll do a post about it shortly.




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Lightsuit V2.0 (part 2)

In a previous post, I provided an overview of the “next generation” of my Christmas Light Suit (and various ‘peripherals’ ūüôā ¬†Really…it’s more like “generation 5 or 6” since the Light Suit has been through very many iterations, starting with just a couple strings of lights powered by a big-ole 12V UPS battery…


By this point, I had an Arduino-powered “Master” controller, which had 3 or 4 simple, pre-programmed sequences I could run, or all-on-or all-off. My suit lights were driven directly by the Arduino through a 4-port triac board, and other pins of the Arduino were connected to an XBee in transmitter, set up in “virtual wiring” mode, so receivers in the Cape, LakewayLightGuy’s suit, and the two Staffs, which had XBee recievers, echoed the pin outputs from the Arduino, effectively syncrhonizing all devices. I experimented a bit with sound-synchronization, but the ambient noise tended to be so high most places we went, it wasn’t really noticeable. There’s a lot more detail starting in this old post.

A big change was moving to ESP8266-based wireless ‘peripherals’ instead of XBee (although I also kept the XBee for now, for backwards compatibility). Although this means there’s a bit of a lag between sampling the octave levels of my sound source and actually getting a signal to the controllers, there are several advantages.

Independently-Addressable RGB LEDS

As I mentioned last post, this year I cranked it all up quite a bit, and it got even more complicated, but ultimately I hope it get’s a bit simpler. For example, Switching from commercial Christmas light strings to strings of WS2811 LED’s meant I had to incorporate a board that supported the WS2812 protocol, but I got rid of the¬†inverter necessary to boost 12V to 120VAC and the Triac board necessary to do the switching. I also get 256 levels each of RGB intensity, addressable per bulb! By the way, WS2811 and WS2812 use the same protocol..just google for many discussions of the difference.

The ESP8266 supports the WS2812 protocol (I originally used this library, but it’s now also available via this online NodeMCU firmware build tool), so I can send RGB bytes of data over WiFi and have multi-color, varying-brightness, synchronized devices. Now, instead of just using XBee “virtual wiring” to echo the on/off state of GPO pins, I send packets of 3 bytes each to set the RGB values of LEDs on synchronized devices. Actually, packets are 4 bytes – I use a one-byte header to ensure receivers are in sync as they read bytes, although I think the UDP packets are received ‘atomically’, so this may not be necessary. ¬†Right now, I just send one color, but I could easily make my over-the-air protocol more sophisticated and send longer strings of ‘colors’. Receivers (‘slaves’) can either use PWM to just¬†adjust the intensity of attached LEDs, or use the WS2812 library to send data over a GPO pin to one or more addressable LED’s.

Inexpensive, Prolific Peripheral Devices

Another BIG reason I wanted to get away from XBees – they’re expensive! Like, $20/ea minimum. ¬†With ESP-01’s running as low as a couple USD from China, you can build synchronized slave ‘peripherals’, like LED hats and batons, for as little as < $10. I got a few LED novelties from¬†Windy City Novelties¬†and by just adding an ESP-01 a little CR123A lithium battery, a really simple socket, a cheap switch, and wiring an output to the existing LEDs, I can have a synchronized Elf hat, for example. In this case, I just used GPIO2, in PWM mode, wired directly to the existing LED’s in the ornaments of this Elf hat.

But since the ESP8266 also supports the WS2812 protocol, by adding a few WS2811’s and wiring GPIO2 as the data pin, I was able to have a multi-color “wand” that pulsed in sequence with other devices.


WS2812 strip

In the future, I’ll incorporate WS2812’s into more accessories, like Santa hats. I bought a¬†whole strip of them, so on a piece-by piece basis, they are pretty cheap.

It’s also worth noting that my suit itself is now a “slave” – the “master” control unit is completely independent of the suit-driving unit, also built around and ESP8266 (in this case, an ESPToy, which had built-in 3.3V regulation and plenty of GPO pins). This way, I don’t have to carry around as much hardware if I don’t care about sound and synchronized patterns across devices. Or I can even flash the suit unit as a “master” that just does simple (non-sound-responsive) patterns, since the difference between a UDP packet sender or receiver, Access Point or Station, is totally software driven. Here’s a schematic of the suit driver:SuitController

Note that this circuit includes a binary-coded rotary switch. I included this specifically so I could load more complex code which can behave differently depending on the switch setting – acting as a slave in one position, or as a master with one of a couple simple pre-programmed patterns in the others.



Using the WS2811’s dropped my power requirement down to 5V, but this introduced it’s own complication – I had to add regulators to ¬†drop the voltage¬†down to 5V. Even then, I wound up using TWO regulators, both with heat sinks added to them, and they were still getting excessively hot, as were the packs of 10 AA LiPo’s I was using for power. ¬†After the fact, I experimentally tried dropping the battery supply down to 6V and¬†voila! Not only did nothing get hot, the whole suit ran for about an hour an a half on a singe set of 10 batteries (rigged as 2 x 5 in parallel). This is¬†much better, and I’m still not entirely sure why. The Buck regulators I use are supposed to be very efficient, but I suspect that may not be the case¬†under high current draw and maybe as they start getting hot. In any case, for future holidays, I’ll be putting together 6V packs.


More on Sound

There are a couple more aspects of the sound circuitry, beyond what I talked about in Part 1, that I should probably mention. Here, again, is a block diagram, and also a schematic, of the “master” controller.


Teensy Audio Adapter schematic

I mentioned that the Teensy was really convenient for the complex audio manipulation I¬†wanted – specifically FFT octave analysis and some audio delay, so that the audio out would be in sync with packets received by the slaves, which lagged by about 1/4 second due to WiFi propagation delay. One snag I ran into was that the RAM on-board the Teensy is only sufficient for an audio delay of about 180ms – I actually needed about 250-300ms. The ADC and DAC pins also require a bit of supporting circuitry – to level-adjust the input voltage of the Analog-In and to smooth the Digital-Out to an analog waveform, respectively.¬†While the inventor offers an Audio Adapter that I believe addresses both the RAM issue and the Input/Output conversions, it would have been¬†yet another board, plus, you still have to solder a RAM chip on to get the expansion and it would have cost another $20 or so, all in. The ADC and DAC example circuitry is provided in the online, graphical, audio patching tool when you choose those nodes. It’s pretty straightforward, so I just built it in myself. I had also corresponded briefly with the owner on his forum and he had suggested adding a RAM chip directly. I wasn’t sure where to start with that, but, upon inspecting the RAM portion of the schematic published for the adapter, I also realized that it’s just an 8 pin chip (available in DIP a package) connected to four pins of the Teensy, plus VCC and Gnd. I just added a DIP socket to my perfboard layout and wired it in – it worked on the first try on my protoboard! ¬†All in all, I really like the Teensy/ESP8266 combination, especially for the kind of complex, audio-related code I needed.

Here again is the final “master” assembly, consisting of the Teensy for audio sampling and delay, passing 3-bytes, representing 3 octave ranges, to the ESP8266, which is responsible to communicating with the “slaves”. The Teensy also provides basic I/O pin-based signals to the XBee for backwards-compatibility with my original cape and staffs. and with LakewayLightGuy’s orginal “secondary”, triac-driven suit.

It’s worth pointing out that I did make a minor improvement to the XBee setup. I converted the cape over to an ESP8266 receiver, did some surgery on the 110V lights strings inside it to be many parallel sefments¬†of fewer LEDs¬†in series (about 15), and then used Buck/Boost regulators to boost 12V to 30V, and added a couple of darlington transistors to drive the 30V segments. These I drive via the PWM pins from the XBee, instead of just on/off IO pins. If you look closely at the above schematic, you’ll see I’ve wired both kinds of pins to the Teensy. I also changed the bases of the transistors in the staffs to be driven by the PWM pins from the XBees. So, depending on the software I flash to the Teensy and the configuration I flash to the XBee’s, I can still go with the old, on/off style of synchronized lights and pre-programmed patterns, or I can drive the PWM’s with 1024 levels of brightness, providing a much better “pulsing” responsiveness. That’s a great thing in general about this controller – now that it’s all assembled, it’s largely¬†software configurable!

I’ll conclude this long and rambling blog entry with a link to a little video of the modified cape, along with a modified staff on the left:


Continue reading

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Using ADC with the ESP8266

The ESP8266 family of boards still amaze me with their size and cost-effectiveness, but I will confess; the dearth of official information for some of the more esoteric features can be annoying.

For my remote garage-door sensor, I wanted to determine the angle of the sensor using a 3-axis accelerometer. The docs¬†don’t really tell you much, but they do mention that the ADC pin can be used to measure the battery voltage or an external voltage, but you have to choose which one. I didn’t see this at first, having googled elsewhere and found an example, but from googling, I did learn that the external voltage you’re measuring¬†has to be between 0 and 1 volts. I think you may be safe going up to 3.3, but it will read a value of 1024 for everything over 1V.

OK, no problem – I added a couple resistors as a voltage divider (see post on garage door sensor for schematic) and I started getting reasonable values instead of nothing but 1024.

Now comes the weird part.

After ¬†putting everything together more permanently for “field testing”, I was suddenly getting nothing but¬†65535! So, more googling and I come across posts like this one describing how you have to define¬†the correct¬†app/include/user_config.h before building your firmware (guess I should have read the docs :-)). Well, I enjoy hacking with these suckers, but my enjoyment ends with building the firmware using build chains. Fortunately, there’s an online tool for building custom firmwares. This is what I had done, since I needed MQTT support. Otherwise, I just stick with downloading the latest pre-built firmware. The posts mention modifying¬†the byte at position 107 in the¬†esp_init_data.bin that is generated from the build as another option – presumably this is generated separately by the build tool.

So, apparently, the firmware I’m using is set to report the battery voltage. I changed my read(0)’s to readvdd33() and started getting values that varied slightly. This is weird, because I SWEAR it worked – using the same firmware – when I had it bread-boarded, but¬†it WAS a different chip, so I guess somehow that value was set differently, despite using the same ROM image. I had generated the ROM using the online tool, so I’m guessing the generated ROM does not extend into, or include, this chunk of init-data space. I got the pre-built¬†esp_init_data_default.bin from the source repository¬†and used a hex¬†editor to change the byte at position 107 to (hex) 0x33 (I had to search around to figure out the value, too – leave at zero for battery sensing). You can grab my pre-edited file from here.

Lastly, there was some ambiguity around where to flash this to. If you have a 512KB Flash space, you flash it to 0x7C00. I’m using an ESP-12 and this didn’t work. Turns out ESP-12’s have a 4MB flash. For those, it needs to be flashed to 0x3FC000. I just used the ESP8266Flasher.exe tool to flash the file to the correct location:


After flashing the file to that location, my 0-to-1024 external values were back :-).

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Remote ESP8266-based Garage Door sensor

I’ve got a bunch of z-wave light switches and plugs in my house and I use OpenHab as my centralized home automation system. I have a detached garage and neighbors¬†have experienced¬†occasional break-ins in similar garages where people stole tools and what-no. In fact, a couple years ago, the padlock on the sliding lock ¬†was broken (yes, sadly, I do not have a garage-door opener…really embarrassing for a home-automation guy..but I’ve got this really funky pivoting metal door that reminds me of an aircraft hanger or something. Anyway, suffice it to say, motor-driven opening would be challenging.) ON closer inspection, I realized it was because someone had been hammering on it…I guess one night while we were out of town or something, because hammering a lock on that metal door would be¬†loud.

Now, one problem is, I’m pretty forgetful, so there have certainly been times when I forgot to lock it, or even forgot to close it. Since I already had z-wave going on, I figured I’d try a z-wave tilt-switch. I set of OpenHab so that when the garage door state changes, I get a text. It also reminds me after sundown if the door is¬†still open. This¬†kind of¬†worked, but z-wave is not guaranteed delivery, and I think the distance to the garage from the nearest node, combined with the RF-blocking metal door, resulted in a pretty poor success rate reporting the ‘closed’ stated (the tilt sensor fires once, then sleeps).

So, I decided I could probably do better using an ESP8266 sensor I built myself.

My first attempt involved setting the ESP (01) leveraging the deep sleep option to wake up every 60 seconds, check the state of an input connected to to a mercury switch, and when the state has changed, connect to my WiFi network and send a message to my OpenHab server via MQTT. I should note that, since deep sleep loses the current run-state – it really just wakes up and starts init.lua from the beginnning) I used an Realtime Clock (RTC) storage register to store the “last known state”..that’s all documented here and there on the web. This work really well, but I only got about six weeks of battery life out of a 3.7V LiPo battery…really two short to be acceptable – I needed to figure out a better design.

I figure, an better approach is one where the sensor is actually powered off most of the time, then powers-on, connects to WiFi, and sends a message when the mercury tilt switch closes, then¬†fires another message when the door closes. The problem is – if I just wire the power through the mercury tilt switch, when the door closes, power is lost and the ESP can’t send the “closed” message. I tried a big capacitor supplying some power for a bit after the tilt switch opens, but even a big-honkin’ one didn’t provide enough juice to run for more than a fraction of a second.

What I wound up doing was using the mercury switch to supply power when the door opens – so on power-up, it sends the “open” message, then I have a parallel power path which uses a P-channel MOSFET to supply power after the door closes. The gate of the MOSFET is connected to a GPIO pin, so the ESP actually powers itself off once it sends the “closed” message by setting the GPIO HIGH, thus turning off the MOSFET. Since the ESP-12 operates at 3.3V, you need a TTL level MOSFET. I used an NDP6020. Here is an example of a circuit which I kind of used as the basis for this secondary power path:relay-mosfet-p-channel-switch8

The at-rest current leakage on MOSFETs is supposed to be really low, so I think I’ll get really good battery life with this approach. I didn’t worry about the diode, and an¬†ESP-12 is basically in place of the relay.

I did need one additional sensor, since I couldn’t think of a simple way to have the mercury switch act as both a power supply switch AND a GPI sensor. I had a couple 3-axis accelerometers around, so I used on of those, with one axis tied to the ADC pin on the ESP-12 through a voltage divider that bring the 1 to 3.3V output down to the 0 to 1V range the ESP ADC pin expects.

Here is a Fritzing and schematic of the prototype:















I’ll deploy it shortly and provide an update on the reliability and battery life in the near future.

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NodeMCU Custom Builds for ESP8266

OK, just a quick blurb in case anyone else runs into this incredibly frustrating experience:

I’m playing with some sensors where I’m interested in really low power consumption. Basically, I want to go into deep sleep, which only draws <100uA, and wake up every minute or so, check an input, and report it to an MQTT broker if the state has changed. I also want to read from a DH11 temp/humidity sensor every 30 minutes or so, and report the values, regardless of whether the GPIO changed. I’m mainly working with NodeMCU right now, rather than “native” SDK code.

SO…the ESP8266 has a “deep sleep” mode, called using node.dsleep(us), which really just shuts off everything but the Real Time Clock (RTC), which drops XPD_DCDC (usually GPIO15) to gnd briefly when the timer expires. Tie that signal to RST, and the chip CPU will initialize when the timer expires and run your code from boot-up.¬†NodeMCU has nifty rtctime and rtcmem modules now that let you read the Real Time Clock value, like after you wake up, and use 128 words of space in the RTC storage to persist info between wakeups.

OK, cool, but after flashing various verions of NodeMCU to my test chips, I get nothing but the following error, presented here for search engine to hit, whenever I try to access the rtctime or rtcmem functions:

“attempt to index global ‘rtctime’ (a nil value)” or “attempt to index global ‘rtcmem’ (a¬†nil value)”

So, my suspicion is, the base NodeMCU firmwares are not being built with the relatively new support for the RTC modules built in. BINGO! After building a custom firmware that includes the module, these functions are available. ¬†I will say, however, that the “rtctime” function desn’t appear to work as advertised. The docs seem to imply you will get the time, including the time that has elapsed while in deep sleep. Currently, I’m not seeing this behavior…it seems like it’s initialized at every boot. Persisting values via “rtcmem” is working well, though, so I can just do simple modulus on an incrementing number I store on every 1 minute “wake” to send temp data every 30 minutes or so.

This being said, a quick shout out to the excellent site, http://nodemcu-build.com/ 

This site lets you build a custom NodeMCU firmware image off the current master (or dev) branch, and include modules optionally, as you see fit. Check it out and donate (as I did) if you find it useful. It’s SO much easier that screwing around with build chains – jsut select the modules you want an click a button – you get an email when your build is ready (almost immediately for me)… and give this guy a few bucks, he deserves it for saving you the time!

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LightSuit V2.0

Well, it’s well past Christmas and things have finally settled down for me a bit, so I figure it’s high time I blog in a bit of detail about¬†my main Christmas technology focus – Version 2 of the AustinLightGuy Light Suit.¬†I’ll post links to resources I incorporated this year at the bottom of this post.

I’ve been wanting to do a major upgrade on the original light suit for some time with these main goals in mind:

  • Upgrade the strands of commercial LED Christmas lights to strings of fully-addressable RGB lights
  • Have cooler built-in patterns and improve the responsiveness of the lights to music when going in “synchronized” mode – both for¬†the suit and synchronized devices.
  • Have MANY, inexpensive synchronized light devices
  • Crank Up the Sound!

I’ll address the last first, since it was the easiest…

Cranking Up the Sound

Turns out most places we go to in our light suits are actually pretty noisy – there’s usually lot’s of people around talking and maybe even other music sources…Christmas music on the PA around the Zilker Tree and Trail of Lights (GREAT job on the Trail of Lights this year, by the way, despite modest entry fees – kudos to organizers and sponsors), music in bars, etc. It would be cool if the Suit could be synchronized to ambient music, but it’s usually kind of drowned out by crowd noise, so I figured I’d try out somethingsuitspeakers¬†else – crank up the volume on the suit.

The original solution, which was just a crummy little set of bluetooth speakers that paired to my phone, was way to quite. So this year, I just got a set of relatively high-powered PC speakers, rigged them up to where they could be snapped on to the new suit, and drove them directly from the line-level audio (which is actually a pass-thru on the new master controller that I’ll describe shortly). They run off the same 12V “power bus” that the whole suit runs on (more on that later). I wrapped them in nice, fluffy faux fur to make them Christmassy.

These pretty much rocked, but in bars, they still got drowned out a lot of the time, so I wound up going with the (single, for now) pre-programmed pattern.


Ok, so now on to the¬†interesting technical stuff…

I wanted to be able to synchronize even more “remote devices” this year – beyond the two staffs, the light cape and LakewayLightGuy’s suit. But I also wanted to retain backwards compatibility with those devices so I didn’t have to completely rebuild them, as well.¬†It just so¬†happens that I had recent been turned on to the ESP8266 family of devices. These are basically¬†amazingly cheap SOC modules that contain a processor, flash RAM, and¬†even WiFi, all in really small form-factors. There are really bare-bones boards¬†(like the ESP-01) incorporating this chipset¬†that can be had for as low as a couple bucks from China, up to more sophisticated boards, like the NodeMCU dev board and the EspToy, which provide good on-board power regulation, USB serial-to-TTL circuitry (necessary to flash them), and LIPO battery charging. There’s a huge community of support out here for these things, two or three tool chains, lots of code libraries, and many excellent blogs, including Pete’s excellent¬†tech.scargill.net. The incredibly low price of these things (especially vs. the pretty expensive and proprietary XBee modules I’ve been using) led me down the path of deciding I should migrate to WiFi-based synchronization using ESP8266-based boards. I played around with a myriad of them, but wound up using a¬†NodeMCU, an EspToy, and multiple ESP-01’s.

Latency Problems

To test the WiFi concept, I cobbled together¬†a prototype setup where I took existing Arduino suit controller and had it feed RGB values via serial port to NodeMCU dev board (the “master”). I wrote some simple LUA code to set the device up as an Access Point, then send UDP broadcast packets out every time it received a set of RGB values over the serial port. I also created a “slave” by flashing¬†a basic ESP-01¬†with a version of firmware that supports WS2811/12 (standard in latest build) and wrote some simple¬†LUA code (based in part on an example here) to connect to the Access Point and listen for UDP broadcasts. When it got a UDP packet, it would pull the RGB bytes out and write them to a short string of WS2812’s I was experimenting with (similar to this). The result was pretty good – although the packet rate is a little low I think probably around¬†10hz, so 10 updates a second, or maybe a tad lower. I tried using my home wifi instead of setting up my master¬†as an access points, but that was actually slower. I really still need to try to recreate the code using the native¬†SDK and C (or preferably, an¬†Arduino sketch) to see if I get better packet rates.

The real problem is – there is some latency between when a sound occurs and the data packet makes it across the serial port, then over Wifi, to the “slave”. The delay is in the neighborhood of a half a second. As a result, the lights are sync’d to the music, but the response lags by about a half second. The delay is more obvious when you ahve it next to one of my XBee “slave” devices, since those respond with almost no lag at all ūüė¶

My first thought was that I could introduce a hardware chip that does audio delay – I did something with a “bucket brigade” chip years ago – or maybe just by an off-the-shelf delay circuit. I didn’t really find anything I like much off-the-shelf…mostly guitar-oriented stuff that was pretty pricey (and big). Then I ran across Teensy! The Teensy (3.2) is a little dev board, with your usual array of I/O pins, but it’s got a 72Mhz ARM processor¬†as well as ADC (analog-to-digital) and DAC (digital to analog) ports. You basically write Arduino sketches and use the “Teensyduino loader” to load your code onto the Teensy. It’s inventor, Paul Stroffregen, seems to be pretty into Audio or something, because he’s got a stupendous audio library and he provides a really cool online tool (built on Node-Red) to wire audio flows together graphically then export¬†code. There are simple examples for wiring line-in and line-out to the ADC and DAC¬†in the help that accompanies the nodes.

Here’s an example, taking and ADC input, piping it through a delay, then feeding the result the the DAC:

Then you just add little bits of code to do stuff like set the delay on channel 1:

delay(0, 300); // delay channel 0 300ms

Since the Teensy has plenty of horsepower, so it can also me my master processor, replacing the Arduino. And Teensy also does FFT, so by using it as my master processor, I no longer need the MSGEQ7 hardware to due octave analysis like in V1!

That’s a lot of stuff going on in my new master controller, so I also decided I would drive my suit, which used to be connected directly to the Triac board in my master controller, via a new “slave”, which would just house an ESP8266 as a UDP receiver and WS2811 driver, and a 12V to 5V regulator to drop by suit power supply down to the 5V the WS2811 strings want.

So here’s the high-level picture:


And here’s the new master and new suit slave:

Complicated, I know. ¬†In the next post,¬†I’ll go into a little more detail on some of this, some of the cool things it let me do, and some additional complications I ran into.



Here are links to stuff that went into this build. Many of them link to Amazon, EBay, or AliExpress, so if they go stale, I apologize. I’ll try to make the descriptions usefully google-able.

Creative Inspire T12 2.0 amplified speakers: http://amzn.com/B0028N6YH0
Teensy 3.2 dev board (72Mhz ARM processor): http://www.pjrc.com/store/teensy32.html
23LC1024 SRAM chip: http://www.mouser.com/ProductDetail/Microchip-Technology/23LC1024-I-P
ESP8266 devices:
* NodeMCU Dev Board: http://nodemcu.com/index_en.html
* ESPToy 1.21: http://rayshobby.net/introducing-esptoy-1-21-with-lipo-charger/
* A bunch of plain old ESP-01’s:¬†http://r.ebay.com/fG130b
XBee Modules: http://www.mouser.com/ProductDetail/Digi-International/XB24-AWI-001
Some cheap, little heat sinks: http://www.aliexpress.com/snapshot/6955208975.html
WS2811 RGB LED strings: http://www.aliexpress.com/snapshot/6890770046.html
2596 Buck Converter step-down regulators: http://amzn.com/B018JPGKQK
Buck/Boost Power Regulators (boost from 5v to 30V): http://amzn.com/B00WMB6OMI


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