DIY Mega328 Self-Test Control for 936 & T12

How to use the mega328 for self-testing control of the 936 and t12?

If you’re interested, keep reading.

· Automatic Identification: Use a temperature-compensated NTC and voltage divider with a 936 thermistor to automatically identify between T12 and 936.

· 936 Temperature Control Process: The thermistor’s voltage divider is amplified by an LM358 (with a lower gain) and sent to the Mega328 to determine the current temperature. The program then decides whether to continue supplying power for heating.

· T12 Temperature Control Process: For the T12, measure the voltage at the heating end (with a series resistor connected to a voltage regulator; full voltage indicates power supply, while less than full voltage represents the actual thermocouple voltage). This is then amplified by another LM358 circuit (with a higher gain) and sent to the Mega to determine the current temperature. If it’s below the set value, power is supplied (using (set value - current value) * 10 ms).

· Features Implemented: Both 3-minute sleep mode and 10-minute soft shutdown are functional.

· Drawbacks: The potentiometer used for adjusting the temperature is unstable. The microcontroller has a reserved interface for replacing it with an encoder.