Red, yellow, green – on the new DIY circuit board of the IoT Octopus there is space for three LEDs, with which the CO 2 traffic light becomes a “real” traffic light . Like the original Octopus, the new circuit board can be adapted extremely flexibly: It can be used with various microcontrollers and CO 2 sensors. In addition to the LEDs, displays in Featherwing format from Adafruit or neopixel rings can also be connected.

2000 of these boards we give away together with the IoT workshop.

Simply plug in So that you can quickly start building your own traffic light, we present two simple variants: In addition to the CO 2 – Sensor Sensirion SCD 28 you need a Wemos D1 mini as a microcontroller (which is available, for example, with our Node-RED Special). We have selected two possible advertisements for this purpose. A 7-segment display with four digits can be plugged onto the feathers base of the board. If you prefer to build the “real” traffic light with the colors red, yellow and green, you can finally solder in three colored LEDs.

Assembly CO2- Traffic light (5 images) The CO 2 sensor should lie as flat as possible.

We have already prepared the necessary code for both variants and uploaded to Github. There you will find ino files for the Arduino IDE as well as the abp files (Ardublock) for the graphic programming environment of the IoT workshop. With the Ardublocks you can also quickly assemble your own programs for the other traffic light variations. For more information on how CO 2 traffic lights work and how to work with the Ardublocks, see our article in the current issue of Make.

Our campaign How to get one of the circuit boards: Send us an informal letter with an addressed and with 80 Cent prepaid envelope (for mailings ins Abroad 1, 10 Euro). The first 2000 will receive their envelope with a board back. Please do not send multiple envelopes – we reserve the right not to send a circuit board in the event of violations. The closing date for this promotion is 18. November 2000, the postmark applies. If our hardware stock is already running low, we will send you exclusive make stickers as replacements.

Please send your letter to the following address:

Maker Media GmbH

Keyword: CO2 traffic light

Karl-Wiechert-Allee 10

30625 Hanover

More on this topic can be found in issue 5 / 20 the make.

The board is an empty circuit board, the other necessary components must be purchased separately. Get the SCD 30 You currently work at Mouser (43 Euro, plus shipping). At RS Components it should be available again from the beginning of December, where it costs around 72 Euro (plus shipping) and at Digikey it is sold out (price around 54 Euro, plus shipping). Adafruit’s 7-segment displays on Featherwings are available in different colors, currently for around 10 Euro from Digikey and Distrelec as well as directly from the New York manufacturer. (hch)