Quoi de neuf 2021
From Eric
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* I have moved my lab to a new, much larger, room: [[File:mylab2021a.jpg|800px|thumb|none]][[File:mylab2021b.jpg|800px|thumb|none]] | * I have moved my lab to a new, much larger, room: [[File:mylab2021a.jpg|800px|thumb|none]][[File:mylab2021b.jpg|800px|thumb|none]] | ||
* Waiting for the transformer to drive a CRT (see [[Quoi de neuf 2020]], december). | * Waiting for the transformer to drive a CRT (see [[Quoi de neuf 2020]], december). | ||
| - | * I have created a LED "spectrum analyzer" using an electret microphone, a 5532 op amp (see [http://www.michelterrier.fr/radiocol/detail2003/preamp-electret.htm#Antoine here]), a BA3830S spec. anal., and a [https://www.ti.com/lit/ds/symlink/lm3914.pdf LM3914] LED display driver. Nothing very complicated, but just a way to occupy time. Here is | + | |
| + | * I have created a LED "spectrum analyzer" using an electret microphone, a 5532 op amp (see [http://www.michelterrier.fr/radiocol/detail2003/preamp-electret.htm#Antoine here]), a BA3830S spec. anal., and a [https://www.ti.com/lit/ds/symlink/lm3914.pdf LM3914] LED display driver. Nothing very complicated, but just a way to occupy time. Here is the schematics [[File:spectrum_analyzer_led_schema.jpg|400px|thumb|none]] and the PCBs [[File:spectrum_analyzer_led_pcb1.jpg|400px|thumb|none]] [[File:spectrum_analyzer_led_pcb2.jpg|400px|thumb|none]]. | ||
* 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 ralays them to a MQTT Mosquitto server running on an RPi... | * 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 ralays them to a MQTT Mosquitto server running on an RPi... | ||
Revision as of 14:55, 21 February 2021
Experiments carried out in the past (from 2011) are described hereafter: 2020, 2019, 2018, 2017, 2016, 2015, 2014, 2013, 2012, 2011
February 2021
- 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.
- 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:
- 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:
- 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 osciloscope. 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).
January 2021
- I have moved my lab to a new, much larger, room:
- Waiting for the transformer to drive a CRT (see Quoi de neuf 2020, december).
- 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
.
- 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 ralays them to a MQTT Mosquitto server running on an RPi...
