Building a circcuit with Arduino, Axial Fan, Peltier Module and Humidity Sensor

Other Hardware Sensors
1

Hi,

I'm building a circuit to regulate humidity in a box using a humidity sensor, axial fan, and Peltier module. The humidity sensor would sense when the humidity rises above a certain level, which would activate the fan and the Peltier module. The humidity sensor would then measure when the humidity has lowered to a certain level, which would deactivate the fan and the Peltier module. The humidity sensor has a operating voltage range of 4 - 5.8 V, so it can be powered directly from the Arduino. The fan is 12 V, whilst the Peltier module would need a supply of 4 V and 1 A. They will be powered by a DC power supply, and two power supplies can be used if necessary.

Does anyone have any thoughts on building this circuit? I'm struggling to get my head around how to power the Peltier and Fan of different voltages, whilst the Arduino controls when they are activated. I'm a bit of a novice with Arduino so any tips would be greatly appreciated. :slight_smile:
Peltier Module: https://uk.rs-online.com/web/p/peltier-modules/1743132
Humidity Sensor: https://uk.rs-online.com/web/p/temperature-humidity-sensor-ics/5283171?cm_mmc=UK-PLA-DS3A-_-google-_-CSS_UK_EN_Semiconductors_Whoop-_-Temperature+%26+Humidity+Sensor+ICs_Whoop-_-5283171&matchtype=&aud-826607888827:pla-420937719811&gclid=EAIaIQobChMI4ND4xr-B9gIVDO7tCh0rEAWqEAQYAiABEgKCYvD_BwE&gclsrc=aw.ds

Thanks!!

2

Please check that again!

3

Relays or mosfets are common solutions.

4

I did something broadly similar some 35 years ago. In an attempt to calibrate Dewpoint RH instrumentation.

I found the heat from the fan's motor made the RH very hard to control :-(.

This was pre uC days and I was unsuccesfully using analogue control.

Good luck, just be aware of this problem.

5

You will need a 12V power supply capable of supplying 4 Amperes just for the Peltier module, but that will run the fan as well.

A 12V to 5V step down regulator can tap that power supply to run all the rest of the electronics.

You will need excellent heat sinks on both sides of the Peltier module, one to condense moisture on the inside, with a handy drain, and the other to exhaust heat on the outside, 40-50 watts when the Peltier is running.

Using the Peltier module as a dehumidifier will refrigerate the box. Conversely, if you keep the entire Peltier setup inside the box, the box will heat up rapidly.

Do you have a plan for somehow maintaining the temperature inside the box, or does that not matter?

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