1-Wire Automatic Discovery Feature - Pushed to the Limit!


I was curious to see how many 1-wire DS18B20 sensors Cayenne could automatically discover. To my delightful surprise, 9 DS18B20 sensors were automatically discovered, without me having to add a single widget. Total time: ~ 20 mins. With the majority of time spent wiring each DS18B20. Unfortunately I ran out of additional DS18B20 to connect…I’ll have to update this post when I exceed 9. Thanks for checking this project out!


  • I used the web dashboard for adding the DS18B20, but the widgets also appeared in the app.

  • I used two types of DS18B20, 5 normal sensors and 4 waterproof coils. I used a 4.7K resistor for each DS18B20.

  • Each DS18B20 is connected to GPIO Pin 4. I used a small breadboard to connect each sensor to GPIO Pin 4.

  • I installed Cayenne, powered my Pi off, connected the 5 normal sensors, powered my Pi back on, and verified that all 5 DS18B20 automatically appeared on the dashboard. (Had to wait a few seconds).

  • I then powered my Pi off again, connected the remaining 4 DS18B20 waterproof coils, powered my Pi back on, and the remaining 4 DS18B20 waterproof temperature coils appeared in my dashboard.

  • Interesting to see the variation of temperature between each sensor.



Love the breadboard… and they call it “1 Wire”

Just a hunch but I would say that only one 4k7 is all that is needed if they are all in parallel…

~ Andrew


Yeah, I must have had a mis-wire when adding in parallel…that’s why I ended up going with a single resistor per DS18B20.


Makes perfect sense to have 27 wires for 9 one wire sensors if you understand beer math-

Given 6 Soldiers
and each Soldier gets 2 beers
that means you need 17 cases of beer

feel free to ask me any questions on this particular subject, I’m an expert




I have put on a breadboard 56 (8X7 array)- DS18B20 and 1- 4k7 resistor They were all detected automatically




Welcome to the Cayenne community!

Photos please!





1wire master controler DS2482-100

That is VERY cool, not very practical, but very cool!

Thanks for sharing Pet!



Hmmmmmmmm The Temperature version of the Matrix :slight_smile:
~ Andrew


It’s a DS18B array, get a small LED torch ans shine it in close up to the middle, centre will be hotter and fad out near the edges and corners. Voila, demonstration of CCD or pixel array (as such ;-)).

If you can get the display to be the same as the 7x8 matrix you have, even better.


Long Wave Ird camera…
~ Andrew