PIC controlled soldering iron

I think an H11L1 would be easier to adapt to PWM https://www.electro-tech-online.com/custompdfs/2012/03/AN-3006.pdf page 3
Going to revise my power supply to use a triac just for the heck of it.

power supply schematic

hopefully it comes out large
At present I am using two transformers a 24vac for heater and a 12v dc for the pic circuit

Looks reasonable enough.

Yes a triac can be on with no gate voltage, buit not for long on ac.
Once triggered the triac stays on untill the voltage across mt1 and mt2 goes through zero, then it turns itself off.
If you went for the moc3040 the datasheet tells you how to connect to an external triac, there might be a delay in switch on and switch off of the triac from the input signal, but it will only be 20mS max (1/2 mains cycle), I dont think this would be an issue for your design.

Triacs have diffo trigger currents for the 4 mains quadrants, so long as your gate resistor is correct this wont be an issue for this application, esp seeing as your load is resistive.

Did you ever finish this?

YES it works pretty good.
Only issue I have is the iron itself. I bought off of Ebay and it does not withstand any temps over about 400degrees F. The metal to plastic? rubber bond came apart. Other than that It works great. It heats up very fast, I bought a temp meter and calibrated it. Works as planned just that counterfeit soldering pen. Supposed to be a HAKKO but its a copy.

Hi!

I realise this thread is four years old but I bought one of those Tenma soklering-stations with the blue LCD in the black case and I'd like to try Mr DEB's schematic to replace the original which has failed - can anyone re-upload it for me please?