I’ve done this before and obviously didnt learn my lesson. I copied the circuit onto the coppered side of the stripboard so I can mark the points to cut the tracks, and then did the cuts before I put the components on! But of course, when I turned the board over, its reversed everything!

Deep breath, and repeat: I’m a noob, I’m a noob…

I had to wait for the thermistor and other bits to arrive through the front door, so took some time to try and find some software to help mock up the stripboard layout. I found one for Windows 8.1, but its not perfect. I might just try to do it in Word or something. Anyway, the final bits arrived,  and got installed into the breadboard, and amazingly, it WORKS!

Functionally, I measure the temp every few seconds, and map anything between 30 and 50 degrees to a duty cycle of 90 to 255 PWM output. (90 is about the slowest this fan will go). I’ll document the code in another post, when I’ve got a circuit to show. I do a bit of a trick with the constrain statement to get the transistor to kick in.

Ok, my first project is a replacement for a previous gadget I’d knocked up to cool my devices under my TV, as they are in a new cabinet with very little vertical headroom.

The current one just adjusts the voltage to the 12v PC fan with the aid of a variable resistor, and a thermistor. Set to the right value, the voltage to the fan increases to its startup level when the temp goes a few degrees above ambient.

My brief for my Arduino powered one is to use a PWM fan, and adjusting the ‘duty cycle’ based on the analogue input from the thermistor. Also, I wanted to add an LED for feedback, and a transistor to turn off the fan completely when the temperature is around room temp.

As you can see, I’m not there yet. Stay tuned.


I have very little electronics knowledge, but I do know what end of a soldering iron to hold, and which way around a diode goes. But as a self-confessed tinkerer, fixer, experimenter and gadget freak, with decades of coding experience, it was only a matter of time before I crossed paths with Arduino, or its fruit-based cousin. Yesterday, with a new Arduino Nano firmly planted in my breadboard, I had that LED blinking. Not just the on-board one either, oh no, I’m talking a proper, red, 3mm LED, with a pull-up resistor and everything! (Or is it pull-down, I can’t remember?). This could be a lot of fun.

This site, I hope, will be a record of a journey. It won’t be pretty. There will be mistakes. I bear no responsibility for any injury you might incur from following any instructions you might read in these pages. I will however, try to illuminate, literally, and metaphorically.

You’re very welcome to keep me company…