Schematic:This is my old V1 schematic. Todo if you want a better board:
-Use a MSP430G2553 MCU (more pins and flash)
-Use a non EOL thermocouple driver IC: MAX31855KASA+
-Add in a FT230XS for a USB interface
-Add flyback protection to relay LSD if a mechanical relay is used.
Thermal-couple: (Important that it is low thermal mass and rated for temp range)
Digikey: 290-1911-ND
Thermal-couple IC:
MAX31855KASA+
MAX31855KASA+T
Relay: (this is a mechanical relay. I salvaged a SSR for my V2. I highly recommend you use an SSR for long life and quicker switching times)
Digikey: T9AS1D22-5-ND (Relay)
+ a 16x2 LCD display
+ some dip headers that are used for jumping and programing.
+ 5mm/.2in lead spacing terminal headers for relay and thermocouple input.