Digital thermometer

Arduino 'Uno' board and temperature sensor board

L: MCP2210 USB to SPI; upper R: LM35D; lower R: MAX6675

My fun with measuring temperature continues while waiting for the solder-mask stencils for reflow-soldering to be prepared. I have been using the LM35D temperature sensor chip. It doesn't require a thermocouple as the chip itself produces a voltage related to its own temperature, ( 10mV per degC ), and because the chip generates almost no heat, its temperature is nearly identical to that of its immediate surroundings. It's accurate to within about 0.5C. This time, because my DIY development board, ( MYDEV2 ), is otherwise engaged, I have been using my Arduino 'Uno' board with Atmel Atmega328P-PU microcontroller. I use the Arduino's analogue to digital converter to sample the voltage produced by the LM35D and then I process the 10 bit digital value to get the temperature for displaying. For no reason other than to use the second row on the display, I've also added a timer to count the seconds which have elapsed since the last program upload or reset.

I might make another for use as the workshop's digital thermometer.