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DHT11 on Edison with Python mraa


Hi guys,

Could you please take a look at the question I've recently posted on SO regarding problems with DHT11: python - DHT11 sensor failure on Edison whereas working successful on RPi - Stack Overflow

I read some threads here about one-wire devices workaround but I don't fully understand it and maybe do something wrong. Furthermore, nobody ever experienced those IN/OUT switching port problems on RPi. It is also a genuine computer system with real time OS, isn't it?

Thank you in advance,


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Valued Contributor II

The 1-Wire protocol, as you know, requires deterministic timing. It is not possible to do deterministic timing on a computing platform like Edison, or even a PC. You might get somewhere close to it using usleep() but your app may get interrupted at any time, thereby messing up your timings.

What you need to do when using a system without deterministic timing of GPIO is attach the sensor using an interface. That interface should use a small micro which DOES have deterministic timing. (ie a Pic, ATTINY, etc).

  • OR - Use an existing peripheral on your system which does have deterministic timing, such as a UART.

I wrote a blog-post some years ago on how you can use a UART to do 1-Wire protocol. You should be able to find it here:

Community Manager

Hi guys,



First, I want to say thanks to SpiderKenny, we really appreciate your help in the community. And Bart, I recommend you to try SpiderKenny's suggestions, in case you need more information take a look at this thread created by SpiderKenny:



I hope you consider this useful.





Leonardo R.