What did you build today (Pictures) ?

  • @NeverDie a big thank you as I was inspired by many of your post and this was my first Nrf5 project. The backplate is designed in KiCAD and then outsourced for etching to one local semi-hobby service. Modules are then connected via precision header pins (concept inspired by Ardumower)

  • Today I finally assembled some of my new PCB's

    2 New front PCB's (a repeater and a LED-Dimmer)
    1 New Back PCB that can be used as just an AC/DC power supply or as part of the AC current side of the LED-Dimmer

    The last inwall repeater I made was just one PCB, and during installation, I got zapped ๐Ÿ˜ข , so I tried to make a 3D design to counter that.
    The part that is the furthest in the wall is the AC side, and the microcontrollers, etc (DC-side) are at the front. Both are connected using 4 pins and are fastened by 4, 3m standoffs

    I think this is much safer when, for instance, the front cover is taken off. (i use the same design as: LINK)

    Pictures show the FL5150 dimmer at the front and its compatible backside.
    When the testing is done, I also want to connect a touch sensor to it, so the dimmer can be controlled remotely as well by touch.dimmer.png

  • Hero Member

    @Omemanti said in What did you build today (Pictures) ?:

    I also want to connect a touch sensor to it

    You may not need an extra sensor. I haven't yet tried it myself, but supposedly the nRF52 has capacitive touch sensing built in.

  • @sundberg84 Nice, I had hanging issues with Domoticz in the past, until I decided to switch to Home Assistant. Best decision ever.

  • Built a heat pump monitor based on mysensors on an Nano board and a few LM393 light sensors.

    It's simply reading the status LEDs and tells me if they're on or off, and it means I can correlate e.g the compressor or circulation pumps with the electricity usage read from the power meter.

    Also, which actually was the main driver behind the project, it allows me to send an alarm to my phone in case the alarm LED goes on. This is usually caused by incorrect pressure somewhere in the system and can be fixed by simply restarting the system. When the alarm triggers, it shuts down everything which is a bit annoying since it can take a few hours before I notice it (usually not until I go in the shower and there is no hot water). I now have to figure out how to deal with the fact that the alarm LED is blinking, which causes a stream of "alarm ON, alarm OFF, alarm ON, ... ." etc messages in Telegram ๐Ÿ™‚ There should be a way to fix this in Home Assistant I hope.

    An interesting thing was that I was not able to tune the sensors to give me an accurate on/off digital signal. I therefore have to read the analog signal, and in the sketch decide whether it's on or off depending on the value. The values are in the 0..1023 range and the threshold was somewhere around 1000, so I think it was too close to the end of the range for the adjustment potentiometer.


  • Hardware Contributor

    @maghac said in What did you build today (Pictures) ?:

    I now have to figure out how to deal with the fact that the alarm LED is blinking, which causes a stream of "alarm ON, alarm OFF, alarm ON, ... ." etc messages in Telegram There should be a way to fix this in Home Assistant I hope.

    You should fix it by using a flag for alarm led on and the last time the alarm led went on :

    • when led gets on, set the "alarm on" flag in your code, save the millis() of last alarm led on in a "last alarm led on" variable
    • in the loop, check status of the alarm led: if off and "alarm on" flag is on, compare millis() with "last alarm led on" time. If the difference is higher than the duration of a blink interval then your alarm is really off.

  • @Nca78 You're probably correct. I first wanted to keep the sensor "dumb" and put all logic in the controller, but it makes sense that the sensor actually returns the true alarm state - which is ON if the LED is blinking.

  • It's s WS2812B LED strip driver using STM32 blue pill and RFM69HCW.
    I have made a few revisions previously, but this one fits an off-the-shelf enclosure and uses the pcb and enclosure lid for strain relief on the LED strip connector wires.
    I like the concept of using the enclosure slots to hold the pcb. Maybe a slightly smaller enclosure next time.


  • Hardware Contributor

    Today, a 5uA always on display with a PCF8553 LCD driver and a GDC1038 LCD from GoodDisplay. Power consumption varies with voltage but mostly with what segments are on/off, but at 3.3V with segments on to display data on all parts of display (2*4 digit numbers and 3 letters) it's always below 6uA.


    Not sure why the Youtube video won't integrate as it should, but here it is for a more animated version:
    Arduino ultra low power LCD (5uA) โ€“ 00:21
    โ€” NicolasVietnam

  • very first working Ethernet gateway ๐Ÿ™‚

    2020-01-31 18.56.26.jpg 2020-01-31 18.56.37.jpg 2020-01-31 18.56.53.jpg

  • Hardware Contributor

    Today I finished to fix failed soldering (too old solder paste made a mess ๐Ÿ˜ข ) on the "motherboard" of my air quality sensor.
    It's based on ESP32, uses a charging IC with power path so it can run on batteries for around a day or stay plugged without destroying the battery, step down from USB/battery to get VCC, storage on I2C EEPROM, flash and/or ยตSD card (depending on use case), one SK6812 mini RGB led as indicator, a small 240*240 IPS LCD (backlight driven directly by ESP32 pin in high drive capability mode), a 3 way switch for basic user interface + footprint for PAJ7620 gesture recognition module, accelerometer and I2C IO expander to manage the 3 way switch and interrupts from sensor modules.
    Sensor modules will be added on top, connected using an FPC connector. At the moment I made only one sensor PCB able to manage usual PM, CO2 and formaldehyde sensors. Only one sensor per sensor board where an attiny841 manages the UART sensor and convert it to I2C, it also manages the 5V step up to power the sensor.
    On the main board I also added an NRF24 footprint so with the same PCB I will be able to make a gateway with integrated battery backup.

    I'm pretty happy with the relatively well aligned components (no, I don't have OCD ๐Ÿ˜„ ) , too bad I had to unsolder, clean and re-solder each component as it now looks botched up. But at least everything (except a missing connection on ยตSD card, hence the blue wire) is working,

    LCD test showing jpgs from SD card

  • My new mini multi device on nRF52810, nRF52811, nRF52832 chips. Designed specifically for a very small case from Aliexpress. It works!!!

    bme280, sht20/21, si7020/si7021, hdc1080, max40009, lis2dw12, lis2dh12, lmt01, reed switch, led + rgb led, user button and 6 analog pins, 6 digital pins with NFC.
    photo_2020-03-15_01-17-39 (2).jpg

    Mini multi-sensor in a small case. New Happy node mode test. nRF52 โ€“ 03:29
    โ€” Andrew EfektaSB

  • Hardware Contributor

    Today I designed a case for EasyPCB with 2xAA holder on the back.


    and a case that slides just over.


    It works with 3x5 version so for this you accually have to use the more advanced option and reflash the fuses on your pro mini to make it 3x5. The normal EasyPCB with booster is 5x5, but Im thinking of just stretching this for another version.

  • Mod

    @sundberg84 just a suggestion; wouldn't it be good to move the batteries to the right (instead of the left) so they block the nrf antenna less?

  • Hardware Contributor

    @mfalkvidd - a great suggestion! It wont not block it completely but as you say, a little less.

  • Hero Member

    Here's another idea too: if you were to add a blank copper cladded FR4 between the batteries and the PCB above it, with a cut-out below where the antenna is, then maybe you'd have a much improved ground plane, making your radio awesome? You could have little drawer like grooves on the side of your case to slide the copper cladded FR4 into position, and, of course, you would want a ground connection to it.

  • Hardware Contributor

    Not sure about that groundplane @NeverDie - you are most probably right but I dont really understand the theory behind it but sounds really cool!


  • Hero Member

    @sundberg84 Here's all the theory you need in one picture:
    alt text
    Most of the modules use a monopole antenna, and as near as I can tell, most of them, if not all of them, have insufficient ground plane. It still works, of course, but it's impaired over what it would be with a better ground plane. I think maybe that's why whenever someone switches to a dipole antenna they generally notice a huge improvement. So, there's always that, but your design is nice because it's so compact, and a dipole would spoil that.

  • Hardware Contributor

    @NeverDie - so a ground plane like in here? Like that mod Pete did in his video but you inmplement it into the 3d case?


  • Hero Member

    Yeah, the flat piece that the red line points to. I'm not sure what those black spray painted things are, so I'm ignoring those.

  • Hero Member

    Made a dead-bug op-amp circuit to help measure open-circuit voltages created by nano-amp currents generated by a solar cell illuminated by just 1 lux of very dim light:
    alt text
    This picture is actually just the LDO part of the op-amp circuit, where I was able to solder the prescribed surface mount capacitors directly between its pins. The larger circuit is described on this thread: https://forum.mysensors.org/topic/10812/the-harvester-ultimate-power-supply-for-the-raybeacon-dk/122
    Why dead-bug you ask? Since the circuit depends on the correct measurement of the effects of mere nanoamps, I didn't want any leakage currents that might happen on a protoboard, which can be significant when it's just a small number of nanoamps and their effects that's under scrutiny.

  • Hardware Contributor

    Updated my GW with the code @mfalkvidd provided to monitor OK and NACK


  • I got tired of twisting DuPont cabels to get from different programmers to different boards.
    This is an adapter that lets me connect the programmers I commonly use (Jlink-mini, BMP, STLink clone) with the boards I commonly program with straight through wires. I left a couple unpopulated for future in and out.


  • Admin

    Finally I am starting to do a little electronics again.. First thing is a prototype assembly of RASLE (Rpi Arcade Sound and Light Extension). It's a custom made arduino "coprocessor" for a raspberry pi, built into retropie arcade cabinets. It's a joint project with a couple of friends that are building arcade cabinets (I built mine a couple of years ago, I think that there is pictures earlier in this thread).



    • stereo 3W class-d amplifier
    • atmega328p
      • 3 pwm channels for LED strips
      • a port for WS2812 type led strips
      • pwm channel for fan
      • output for a relay to control mains input for the box (let the rpi shutdown cleanly, before disconnecting power)
      • 5 button inputs (shared between rpi and atmega)

  • Hi, finished two nodes based on the same multi-purpose battery powered pcb (all the documentation here)

    One is a door / window sensor based on a Reed switch.

    20200223_175402.jpg 20200223_175502.jpg

    If someone is interested, the dedicated wiki page contains the detailed build instructions.

    The other is a soil moisture sensor.

    final-1.jpg cover.jpg

    For this one, the wiki page is here.

    Happy Easter, even if at home!

  • Hero Member

    Anyone know or have experience with how well the underlying capacitive soil moisture sensors hold up over the long term? Clearly they're better than the cheap conductive electrode kind, which for most people don't last very long at all, but I recollect reading that water ultimately invades the PCB enough on even the capacitive designs that it goes kaput. Maybe they've been improved since then or maybe there are now known tricks for how to fortify them against that happening?

  • @NeverDie Good question. My is too young (2 days) to say something.

    Here a possible solution. See at about 9:50

  • @NeverDie The guy with the swiss accent once said that you can coat the capacitive soil moisture sensors with a water resistant varnish or put it inside a waterproof shell.

    starting at ~7 mins.

    @franz-unix Ha, Great minds think alike. ๐Ÿ˜„

  • @BearWithBeard ๐Ÿ‘ ๐Ÿ˜ I love the video of the swiss guy!

  • Mod

    @BearWithBeard ah, now I know who 'the guy with the Swiss accent' is ๐Ÿ™‚

  • Hardware Contributor

    Today I have a very strange problem. I have created a new outdoor sensor which is powered by a 240v-5v HLK module. Its working VERY intermittent and should send data every 5 minutes (no exceptions).

    Whats even more strange is that, when my outside node (called multi) is working, I have a battery powered node (sleep 15 min - send - sleep) that seems to go down, and the other way around (not always, but quite frequent - could be very unrelated but I have notised it a couple of times now).

    Anyhow, Im very glad i build my logger node - works great once more. I use this so often and really recommend all with a bigger network to have some sort of mobile debugger. Most of the times I use the bluetooth module (2xAA powered) but at this point I have my node on my workbench powered by a USB adapter (orange wires). I then parasite power from the node to run the debugger and is now logging everything to a sd-card.


  • Mod

    In case anyone hasn't seen the logger before, it is available at https://www.openhardware.io/view/532/The-Logger-Machine-Short-and-long-term-serial-logging

  • Hardware Contributor

    Another picture from today:

    Just started working with coincells - CR2032 to be exact. Anyone knows why the battery % varies with the given temperature? Are those coincells very temp. dependent or I have made a misstake somewhere... ???

  • Hardware Contributor

    @sundberg84 said in What did you build today (Pictures) ?:

    Anyone knows why the battery % varies with the given temperature

    They don't like it when it's too cold. Check page 4 :

  • Mod

    @sundberg84 looks like you can ditch the temperarure sensor and just use the battery voltage to measure the temperature ๐Ÿ’ช

  • 20200422_132110_resized.jpg

    433 MHz ESP 32 MQTT Gateway with proper antenna

  • Hardware Contributor

    @Nca78 - Well, its been around 14-17dgr C today, so almost room temp. Strange
    @Yveaux - hahaha, best answer! Saving uA!

  • @NeverDie sorry if it's a bit off topic, but I see that 10 pin ARM box connector you use in several of your designs, and I was wondering if it offers anything extra in addition to the regular 6 pin programming pins. I'm asking specifically because I want to try some of your nrf52832 designs, but would like to avoid spending extra money on special connectors and cables. Thanks!

  • Hero Member

    @idanronen No, nothing extra. It just conveniently and transparently interfaces to the ribbon adapter cable used by the Nordic nrf52 dev kits for programming external nRF52 MCU's. If you want to roll-your-own, you can do away with most of the pins. I myself migrated to a smaller connector in later designs.

  • @NeverDie thanks for clarifying!
    So for example in the mini breakout board (https://www.openhardware.io/view/471/Ebyte-nRF52832-Small-Breakout-Board) I could just align the 6 pads and use a standard 6 pin pogo programmer right?

  • Hero Member

    @idanronen Yup. If you have more questions, you should probably ask them on a different thread than this one, as it's off topic here.

  • Offtopic in terms of mysensors platform, but somehow tangent to a home automation. I've made a batch of concrete switches/push buttons which are in this case simple buttons with led backlight and all the logic is located centrally in distribution box, based on KNX ABB module. But I am planning on making smarter and more complex version which could use Mysensors as its transport.
    and a photo of insides of one of the prototypes at first stages of development

  • @monte Nice work! I love the looks of the concrete switches, do you have some links or useful information on how you did it.
    I have a project of a doorbell that could use such a switch.


  • Hero Member

    @monte It's a real pleasure to see such professional looking design!

    I'm curious though: the button in your teardown looks clear:
    alt text
    so how does it turn black and give the solar eclipse effect? I mean, I can see the 4 LED's that comprise the "sun," but how does the button (the "moon" in this analogy) go from clear to black?

  • @NeverDie tanks for describing it as "professional":)
    The clear button on the last photo was one of prototypes as I've mentioned, frankly process of refining the button part to make it work as it should was the longest part of the development. Now it is made in two stages: at first the transparent acrylic part is cut on laser machine, then it placed into a mold with curing mix of resin and concrete, which makes it's black top layer that blocks the light from below. 3mm acrylic base and 2mm resin top layer.
    But I have to say that next batches will be made the other way, which is already in my mind:)

    @MatiasV thanks! Well, I coluld describe the whole process of making, but it requires a lot of work like making propper mold, the process of trial and error while trying to achieve consistant pour and at last the complex process of making a button that would work without sticking.
    Frankly I don't think it's worth time and effort if you plan tho do only one switch for yourself. But I can give you hints about concrete mixture and other stuff, if you're just interested in it's concrete part.

  • Hero Member

    @monte Now that you've mastered the medium you can cast your own tile to texture a wall:
    alt text

    I met a local architect who did such a thing for her own home. She only had to create a handful of different molds, and then random placement gave the illusion of more than that. Maybe they could be secret panels for hiding all your home automation control equipment behind. High WAF that would be. ๐Ÿ˜

  • Admin

    Just made a fun (and useful) sensor / device, using a arduino pro-micro (atmega32u4), and VL53L01 TOF distance sensor.

    It's an auto lock device for my pc, I have mounted the VL53L01 to the bottom of my center monitor, and then have it measure the distance to my body, whenever it exceeds 1m (or is out of range), I increase a counter. When the counter reaches 20 (seconds) I send keypress GUI+L, to lock the screen (works equally well on ubuntu and windows).

    When I return to the desk again, it is detected by the arduino (distance is now under 1m again). And it then sends CTRL+ALT+DEL to start login procedure.

    The arduino sketch is available on https://gist.github.com/tbowmo/7e9934796d47566dc09e7b3bc5b2f208

    next project should probably be to find a better enclosure, and build one for when I return to the office in a month or two, when the corona lockdown is lifted more



  • @sundberg84

    I finished my fully functional panel for domoticz, using Display Nextion ...

    I don't know where to post, sorry !!! lol

    20200514_202815.jpg 20200516_211738.jpg 20200516_211820.jpg 20200516_211810.jpg 20200516_211815.jpg

  • Hardware Contributor

    Interupted by our first "Summer" lightning, but in replacing my old Rfm69 gateway (old one works, but uses a ftdi adapter for Serial communication and i have another need for the adapter). In the same time im taking up signing. The node has a atsha chip but I never used it properly which im going to try to fix.


  • Hi guys,

    today I have finished the 3d printable case of the d-diot hub.

    20200524_101250.jpg 20200524_101318.jpg 20200524_101419.jpg 20200524_101329_HDR.jpg 20200524_101340.jpg

    The hub basically is a Raspberry Pi 3 with the d-diot board (see this topic) that offers the following functionalities:

    • IR Gateway (blaster and receiver) to control every device that has a dummy infrared remote.

    • 433 Mhz Gateway with the RFLink firmware running on the on-board ATMega2560 microcontroller

    • Dual MySensors Gateway: NRF24 (2.4 Ghz) and RFM69 (868 Mhz).

    • Latch circuit to power-on and safely power-off your Pi with a simple button press.

    • SSD1306 I2C Oled display controllable in Home Assistant

    • Radio activity LEDs for IR and Mysensors gateways

    • Nice and powerful web interface thanks to Home Assistant

    • Easy setup and configuration with the d-diot image

    If someone is interested, here the detailed build instructions.

  • @NeverDie My experience shows that the Chinese sensors that are sold on Aliexpress have a low quality printed circuit Board. When used outdoors, they may deteriorate within 1-2 seasons. Inside the house, in a flower pot, the service life is much longer. As for such sensors developed independently, the quality of printed circuit boards that are ordered through the services of jlcpcb, pcbway... very high.

  • @NeverDie I personally took a bottle of nail polish and coated every sensor I had. I had a hunch that moisture seeping might affect the capacitive sensors so I took precautions. They've lasted a year now with no sign of deteriorating.

  • Hero Member

    Thanks! Earlier in 2020 I started a shoot-out of different weatherproofing coatings, and I can already see that Spray Max 680061 is by far performing the best out of all the hard coatings that I tried: https://www.spraymax.com/en/products/product/clear-coats-and-spot-blender/2k-clear-coat/ So, for that reason, I suspect it would also perform very well at moisture proofing capacitive PCB soil probes.

  • Hero Member

    I built a picoamp current source and tested a picoammeter that I built from Gyro's design that was posted on the EEVblog forum. It turns out it can measure even single digit picoamps to an accuracy of less than a picoamp (i.e. less than one trillionth of an amp!)



  • Today I finally found some time to put a few modules together.
    A cheap solar cell (โ‚ฌ1.35 a piece) with recharcheable battery which feeds via a step-up converter (โ‚ฌ0.70 /pc) a pro-mini (5VDC). The DS18B20 is read every 5 minutes.
    Now Iโ€™m Interested how long this sensor will do its job.


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