[quote author="Ryan111"]1- you said that you used a 24V dc laptop power supply but how much current? Is 3A enough?(70/24~3A) [/quote] I used a 90W adapter. The T12 tips are 70W, but it is better to give some margin.
[quote author="Ryan111"]2- My MCU is a 3.3v (unlike your MCU that is a 5v) then I have a problem. there is no problem for transistors (I can bias them) but I don't know how and what should I chenge for Op-Amps?[/quote] You can use 3.3V to drive the transistors without problem, you don't have to change anything or at least reduce a little the R11. In the op-amp you only have to adjust de gain (P1) to ensure that the output voltage is always below than 3.3V
I was just kidding. I dont want a Metcal controller. It is a different functional concept of most soldering drivers. Uses an ingenious way for heating, it's true. My company has one of these Metcal stations and the few times I used it I was not impressed. It is not so quick to heat up, it have a big and heavy controller, sometimes when changing the tip it is not detected, and offcourse the disadvantage of not being able to choose the temperature. Probably the temperature stabilization is better, I don't know.
I finally finished my Hakko T12 soldering controller. Thanks to sparkybg and arhi for all help and sugestions.
Some features of the controller: - 3310 graphic display - rotary encoder for easy and fast temperature selection - sleep mode when the iron is in the stand - turn off when a long time in sleep mode - audible indications - intuitive menu navegation - percentage visualization of output power - powered by a compact and lightweight 24V dc laptop power supply - ambient temperature sensor for a better cold junction compensation - lcd backlight control - alarm for very high temperature, turning off immediately the heater - indication of tip removed to allow hot swapping the tips - bootloader for easy firmware upgrade via integrated usb port - usb port and c# software to monitoring all parameters and help to adjust the pid parameters