Stand alone temperature differential PC fan switch

Projects General Guidance
1

Hi All,

I have been through a few of the intro exercises and would like to move on to a real project.

I want to switch on a PC fan based on two temperature sensors to pull hot air out of a small solar panel (hot air type)

I am thinking of using a small PV solar panel as the power supply for the fan such as this trickle charger type:

1.5w 50Ah Solar Powered Battery Trickle Charger

And to switch the power on and off based on a simple temperature differential via a mosfet to switch the fan power on.

It would appear to be totally possible and within my understanding of the programming.

I want to use an Arduino mini (or mini pro) both to reduce the size of the project and the cost.

I would like the unit to be standalone and run either from a battery (charged by the solar panel) or directly from the solar panel.

My thinking is, that if there is not enough sunlight to power the PV panel, then there will not be enough to heat the main thermal panel, and I don't need the fan on anyway.

Is any of this possible?

Have I made any fundamental errors in my early thinking?

Any suggestions as to what components (and modules) I should consider using and thus start experimenting with.

I 'think' I understand the basics for switching to fan on & off based on two tempurature sensors, but how to make the project standalone and battery based is beyond me.
I understand that this is a lot to ask, but I am hoping someone far more experienced than me might be able to help.

Thank you ALL for any suggestions.

2

Get a 12V 1.5W fan and then yeah...

You will want a voltage regulator for the MCU. A 5V voltage regulator like the LM7805CV would suffice.

A couple of temp sensors, the analogread() method with TMP36 sensors is nice and easy for a beginner.

A capacitor across the MCU to protect the MCU from voltage spikes.

3

Many many thanks, I really appreciate the advice.

I have made a note and will start to research based on it.

Thank you again

4

And to switch the power on and off based on a simple temperature differential via a mosfet to switch the fan power on.

Above advice very sound, I should mention an alternative as you wanted 2 temp sensors. For this the "one wire" DS18B20 sensors are good because you can address them individually using just one wire (plus power).

Check out my YouTube channel for a demo of these devices, cheap and easy to use, it's video #28 you need. URL in the footer of this post.

Just suggestin' :slight_smile:

5

Thank you Ralph, very much appreciated