Project : Cool – Veroboard Layout

pwm-front

Well, rather than struggle with a tool not designed for the job, I threw away any thoughts of doing the stripboard in MS Word. Instead I downloaded the demo of a bit of prototyping software called LochMaster 4.0. It natively does stripboard, and you can even flip the board to see the solder points and cut strips underneath! I’ve now purchased the software, as I think it’s going to be pretty handy.

Anyway, this is the top of the board, the Vin of the Nano is bottom right. The power connection to the red and black rails on the right is 12V. The 5V green rail is taken FROM the Nano, you don’t supply it.

Additional parts :

  • C1 – 0.1 uF cap to make the 3.3V reference voltage smooth.
  • D1 – Small diode to prevent back EMF from the fan. A 4001.
  • D2 – Small 5V LED (this and the resistor are actually entirely unnecessary, as the on-board LED would probably be enough)
  • T1 – The transistor at the top is for switching the fan on and off. I think its a BC337

Regarding the pin strip headers, the top (4-way) is for the PWM fan. The S pin is the RPM pin, and the P pin is the PWM signal pin to the fan.

The bottom 3-way header is for the TMP36 thermistor. Since I wanted to have this at the end of a cable, so I could position it where I wanted, I made it a header.

pwm-back

This is the back of the board, showing the places where the strips need to be cut.

Code is to follow, when I’ve commented it and tidied it up. I’ll mark the Nano pins on my next project. You should be able to work it out from the circuit and the code though.

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