“Handheld thermometer for measuring high temperatures.
Since I’m a pizza lover and I got a wood oven, I built this thermometer for checking internal oven temperature and compare the reading with the analogue one mounted on the oven
This Handheld Thermometer uses a K-type Thermocouple. You can read from 0°C up to 1023.75°C depending on the used thermocouple (most thermocouple reads from 0 t 400°C). You cannot read negative temperatures.
Microcontroller used is an ATtiny85 on the Digistump Digispark. Thermocouple is connected through a MAX6675 amplifier. Readings are showed on a 0.91” (128x32) OLED display with big fonts using the Tiny4KOLED library. Whole thing is powered using a 9V battery connected on Vin pin of the Digispark. Digispark has a 5V regulator on board and its 5V output is used for powering the amplifier and the OLED display.
Even if the OLED controller works at 3.3V is safe powering the display at 5V. Those OLEDS have a voltage regulator on board that step down to 3.3V. SDA and SCL lines are connected on display to 3.3V through pull-up resistors: remember that I2C pulls only lines to GND and when an high logic level must be sent, device put the gpio in high impedance so the logic level is given by the pullup resistor.”