Quoi de neuf 2021

(Difference between revisions)

Revision as of 08:54, 19 June 2021

Experiments carried out in the past (from 2011) are described hereafter: 2020, 2019, 2018, 2017, 2016, 2015, 2014, 2013, 2012, 2011

I am now playing with Zigbee devices.
- I have bought a CC2531 Zigbee sniffer, a small Sonoff bridge and a 4-relay zigbee board (all from AliExpress). Now,n I can control four relays using Amazon Alexa... As usual, interesting but completely useless... The next step is to setuop my own home zigbee server using Zigbee2MQTT.

Building a small custom keyboard using cheap Gateron switches and keycaps, and either an arduino or a bare Atmega (using the VUsb library). See also the LUFA library.

I have setup a esp-link serial<=>wifi converter. This very handy device, based on a ESP8266, allows an Arduino to be programmed remotely (without USB cable).
- After frying 3 ESP8266 due to bad breadboards (and my own stupidity), I have built a small board using my usual combination of solder bridges and wrapping.
  
  I have added a level converter (a YF08E), connected an 5V Arduino pro mini on one side, my board on the other side and, voila!, I can now upload software to the Arduino wirelessly... I have put information and links on a dedicated page. Now, I will build a small PCB to make it more handy.
I have put my CubeCell meteo sensor in a box, added battery control. For the moment the power consumption is much too high. With a supposedly 550mAh battery, the device works for around 24h.
- I guess that this is due to the sensor being powered on permanently. One solution would consist in powerin the sensor via a GPIO, but as my board is fitted with multiple sensors, I am dreading the current being drawn being too high. I'll check and, if it is too high, I'll simply add a FET transistor to control the sensor's power.

I have implemented a minimalistic game using my galvo. See my video (in french).

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2021/03/07
- I have resurrected my galvo project. This is a long story. More information can be found on the dedicated page.

2021/02/21
- The refresh rate of my CRT was much too slow and one could see the display refresh even with 5 characters displayed. So I built a 8-bit DAC using a R2R resistor ladder in order to avoid the I2C latency of the MCP:
- But the Arduino was in any case a bit too slow and has too few output pins. So I switched to an ESP32 (with two cores: one to refresh the display and the other to run some game...). And I discovered that the ESP32 has two DACs (connected to pin 25 and 26)! So I used the two internal DACs. ANd the result is much better. Now, I can display several lines of text without any flickering:
- Now, I'll try to use it to implement some stupid game.
- There is a video here (in french, sorry...).

2021/02/20
- I have managed to drive my CRT! To display text, I combined the Hershey's font definition provided at http://paulbourke.net/dataformats/hershey/ (slightly adapted), and the line plotting code from Alan Wolke (weaew). First, I used an Arduino fitted with two MCP4725 DACs:

2021/02/14
- I have received my russian CRT and have built the power supplies and the plate drivers. See article oscilloscope. Here are a few pictures of the current setup:

I have completed my "sound spectrum analyser" using a BA3830 and a bunch of LM3914N. A video is available here (definitively non interesting). The PCBs have been built by JLPCB (nice and fast. A few pictures are at Sound spectrum analyzer.

I have added a Python MQTT client to log the temp, humidity, pressure, etc. data to a mysql database. I use "sqlbrowser" to display the content of the data base. If I find some time, I'll write a Python HMI. Another solution would be to use an InfluxDb database (optimized for time series) and a Grafana dashboard. See tutorial here. I should also probably move to a more robust RPi distribution (e.g., dietpi) in order to prevent the nasty effect of power-cuts on the file system (dietpi allows to set parts of the file system read-only).

I have created a LED "spectrum analyzer" using an electret microphone, a 5532 op amp (see here), a BA3830S spec. anal., and a LM3914 LED display driver. Nothing very complicated, but just a way to occupy time. Here is the schematics

and the PCBs

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I am also playng with my cubecell. I have attached a solar panel, a battery, and a CJMCU-8128 set of sensors. The guy transmits it data via LORA to a ESP32 which relays them to a MQTT Mosquitto server running on an RPi...

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 ** I have bought a CC2531 Zigbee sniffer, a small Sonoff bridge and a 4-relay zigbee board (all from AliExpress). Now,n I can control four relays using Amazon Alexa... As usual, interesting but completely useless... The next step is to setuop my own home zigbee server using Zigbee2MQTT.
-[[File:zigbee4relays.jpg|400px|thumb|none]]
+[[File:zigbee4relays.jpg|200px|thumb|none]]
-[[File:zigbee4bridge.jpg|400px|thumb|none]]
+[[File:zigbee4bridge.jpg|200px|thumb|none]]
-[[File:ccdebugger.jpg|400px|thumb|none]]
+[[File:ccdebugger.jpg|200px|thumb|none]]
 * I have built two small keyboards using at Atmega32U: [[File:keyboards.jpg|400px|thumb|none]]