heat-gun-firmware
A homebrew dual soldering station (soldering heat gun) with digital control.
For the schematics, see https://easyeda.com/barath.laci10/heat-gun
Note: I am desigining HW AC parts with 240V@Hz in mind. Adjust them to yor needs if necessary!
Project goals:
- temperature control (thermocouple read & adjust output power via phase cutting)
- 858 handle fan speed control & reed switch reading
- simple to use interface using 16x2 alphanumeric LCD & rotary encoder
- safe - no danger of electric shock
- simple to build - 1 layered PCB to make DIY etching possible
- cheap - at most half the prize of an already alaviable one
- opensource - mega328p + arduino code -> repairable
Progress:
- thing is built, firmware is working. Temperature control is working, albeit kinda shitty (simple on-off control), so improvements are possible.
Modules:
Main MCU(Mega328):
- xtal + 2 caps
- IC
- resistor pullup on reset
- (firmware)
- ISP header
LCD
- LCD
- contrast pot
- current limit resistor
Rotary switch
- rotary encoder
Fan speed control
- IRFZ44 fet
- 1N4007 as flyback
- gate pulldown resistor
Temperature control
Temperature reading
- MAX6675 breakout board via SPI
Triac control
- header to external board - 1 pin + gnd
- external board
ZCD (zero crossing detector)
- header to external board - 2 pin + gnd
- external board
Reed switch
- header - 1 pin + gnd
Heater ON
There are some inputs that control (enable or disable) the heating element:
- reed switch in handle
- swtich on front panel (or maybe a menu item?)
Heater is ON (controlled by feedback loop) if and only if reed detects picked up AND switch is on.