HAKKO soldering pencil driver

arhi made a control board for HAKKO soldering pencils. Add a power supply, probably from an old PC, and you have a quality DIY soldering station.

From the project log forum:

Upgrades from v1
1. thermocouple is read properly. The circuit used to get the K-type to go 0-5V came from microchip’s app note
2. 3 buttons are replaced with rotary encoder with button
3. DS18B20 is added to read ambient temperature, thermistor returns difference in temp between hot and cold join so you need to know temperature of the cold join to know what is the temp of the tip.

Software upgrades (not done yet)
1. deal with hardware upgrades
2. use PI or PID instead of simple hysteresis to control tip temperature

It will be interesting to see how the different temperature regulation techniques work out. Anyone know how the big players do it?

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  1. I use Farnell (for me it is cheaper then digikey as I have local company making orders once a week with great discount :D) so I can make a BOM with Farnell links. Note that this pcb is not yet tested, I will be sending it to seeed or itead in few weeks (so it can arrive in august) and then I will populate/test it.. Follow the topic on forum I’ll post news there when I get back from vacation

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