This is my amateur circuit diagram. Anyone with recommendations for circuit diagram software please mention

I am trying to monitor the grain temperature in 4 roughly 25ft grain bins. I currently am monitoring temperature in one 15ft bin with the AM 2302 sensor, and it appears to be working.

I just made a 60ft (roughly 18m) long cable with three sensors, but I have gotten bad sensor readings far too often to be feasible. While testing I did have most of the cable wrapped up in a circle like how you may see an extension cable hanging on a wall, so maybe there is some noise being caused by that. I am also using regular wire and not network wire.

Right now I am thinking maybe I need to use network wire and not regular wire, but I am not sure what the difference is. My other thought is that maybe there is some noise being created, so I may need some circuit to clean up the noise.

I would like to be able to use this sensor up to 30m away from the microcontroller, so my basic question is how do I accomplish this and what am I currently doing wrong?

The Github for my project is here https://github.com/PhysicsUofRAUI/binTempSensor.

If there are any other questions that could clarify my problem please ask. In particular, if there are pictures that could be helpful I have a few for a tutorial I am making and would be willing to take more.


I have replaced the wire I was using with bell wire, and added one capacitor (of the proper size) near the controller. It is working now so I think that must have solved it.

  • 1
    So to start with, I would test a single sensor, (not 3) to make sure that is not the issue. Networking cable would be better, as its shielded better then what you are using. There could also be an issue with how you have them wired together, that is creating additional capacitance, which causes the singnal to not be reliable. Again, starting and testing a single sensor is the best way to trouble shoot this, IMO
    – Chad G
    Commented Feb 5, 2021 at 17:52
  • Also, did you add the suggested filter cap from the datasheet, and if so which end did you do this on, close to the sensor, or towards the receiving end?
    – Chad G
    Commented Feb 5, 2021 at 17:57
  • I did not add the filter capacitor. Sorry, that is a bad oversight on my part. I'll try that and do it using one sensor as you suggested. I'll be putting the capacitor close to the microcontroller. Thanks for your suggestions. Commented Feb 5, 2021 at 18:22
  • Depending on what that gives you, I would try the cap on the other end, or even both.
    – Chad G
    Commented Feb 5, 2021 at 19:08
  • You should probably ask for advice on sister site electronics.stackexchange.com
    – meuh
    Commented Feb 6, 2021 at 8:41

1 Answer 1


Having the right size capacitor matters. Especially if you used a different technology (i.e, you used electrolytic instead of ceramic). Ceramic is much better at filtering out high frequency noise. The electrolytic is good at filtering out brownouts due to sudden spikes in demand. Also, make sure that you have a clean common ground. Try powering the sensor with a battery (just for debug. I'm not telling you to put a battery in grain for production !) and see if things improve. You'd be isolating power supply noise in that case. Twisted pair cables are good for keeping the signal clean from EMI. Maybe shielded too. If all this doesnt work, try a 4-20mA sensor.

Also, 10k seems awfully high for running 30m. Any reason you should not go down to say 500ohms/1k ?

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