Fuz Hackerspace

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====== Operame ======

===== Project information =====

  * Owner: [[:user:Lomanic]]
  * Participants: none
  * Status: **deployed at Lomanic's office**
  * Project created on **Sun 14-11-21** by **[[:user:Lomanic]]**

===== Goals =====
  * Implement [[https://operame.nl/Operame|Operame]], a project from the Dutch hackerspace [[https://revspace.nl|Revspace]] using a CO2 sensor coupled to a TTGO T-Display to tell people in a room that they should open the windows to limit Covid-19 aerial spread indoors
  * Document it in English
  * Maybe extend it in some way (automatic ventilation system?)

===== Hardware =====

  * [[https://www.aliexpress.com/item/33048962331.html|LILYGO® TTGO T-Display]], ''16MB CH340K Chip'' variant
  * [[https://www.aliexpress.com/item/1005001947070873.html|Winsen MH-Z19C NDIR CO2 Sensor]], ''400-2000ppm-Pin Ver.'' variant, difficulty was to buy a genuine version as mentioned on the [[https://operame.nl/Hardware|Hardware page]], the tip is to buy from Winsen official store even if costlier
  * [[https://www.aliexpress.com/item/32861400498.html|through-hole female header pins]] (bought years ago, look around for cheaper options)
  * [[https://www.aliexpress.com/item/32546265487.html|perfboard]] (bought years ago, look around for cheaper options)
  * solid core wire (left overs from other projects)

As I won't order PCBs online (and specific SMD sockets as shown in [[https://www.youtube.com/watch?v=kRH15L6IbI8|soldering instructions video]]) and just use what I have at hand, it will be assembled on a perfboard I had in my drawer for years.

{{:projets:fuz:operame:ttgo_t-display_pinmap.jpg?200|TTGO T-Display pinout, mirrored from https://github.com/Xinyuan-LilyGO/TTGO-T-Display}}

Pinout:
  TTGO T-Display      MH-Z19C
     5V                 VCC
     GND                GND
     D26                RX
     D27                TX

D12 on the TTGO has to be grounded but it's not obvious why

===== Software =====

https://github.com/revspace/operame unmodified, had to install vscode (vscodium doesn't have platformio in its openvsx store) and [[http://www.wch-ic.com/downloads/CH341SER_ZIP.html|the appropriate driver on Windows]] so platformio could flash the TTGO T-Display onboard ESP32

===== In action =====

{{:projets:fuz:operame:img_20211114_123700.jpg?200|The Operame device is shown mounted on temporary breadboards with bridges made of Dupont wires as a proof of concept}}

{{:projets:fuz:operame:img_20211114_171043.jpg?200|Perfboard implementation, front}}

{{:projets:fuz:operame:img_20211114_171053.jpg?200|Perfboard implementation, back}}
===== Log =====

==== 2021-11-14 ====

Initial proof of concept with breadboard, everything works perfectly.

Then perfboard implementation. A first for me, quite the hassle, I probably didn't go the easiest way with the solder traces and then the cables on the back. A multimeter with continuity mode is a must have to ensure there's no short between traces.

Next time, solder traces are not worth the time and headache and cables should just be soldered through holes with a single solder joint to the next hole.
===== Planned =====
  * maybe build another one for the hackerspace, but not convinced at all seeing the general attitude of just being maskless in a basement
  * automatic ventilation system at Fuz? ([[wp>PID controller]], [[http://brettbeauregard.com/blog/2011/04/improving-the-beginners-pid-introduction/|"industry-level library"]] according [[https://old.reddit.com/comments/s3fz4l/comment/hsmomjx|to some dude on the Internet]]), [[https://www.fourmilab.ch/hackdiet/www/subsection1_2_3_0_5.html|bang-bang]])
  * statistics?