A few weeks ago we had the first version of this project, the portable soldering iron V1.0 and that had a few problems. The main problem was the soldering tip that I’ve used. It was very low quality but I wanted that tip because it had the thermocouple and heating element with separated wires. But now, I’ve got a much better tip, the T12. This one has the thermocouple and heating element in series so the circuit is different and the temperature sensing as well. But the results are MUCH better.

PART 1 - Inspect the board
First, let’s see what improvements we have for this new board. First, the Iron tip is not that big and ugly one anymore. Now we use the T12 tip. For taht the board has 3 PCB clips to fit the tip in place. The first clip is connected to nothing. But the two clips in the midle are positive and negative connections of the iron tip. Those connections are the thermocouple and heating elenent in series. To read then temperature, we now use and OPAMP configuration and amplify the voltage drop across the iron tip connectors and then read the temperature corresponding to that drop.”

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