Make: Volume 91

Oxon, Daniel Bachfeld

BUILD AN IOT THERMOSTAT

First we’ll build the thermometer with the NTC

thermistor. This temperature-dependent resistor,

together with a 2.2kΩ resistor, creates a voltage

divider we can measure with the Oxocard’s

analog-digital converter (ADC) via pin IN06 on

the breadboard cartridge (Figure

E

). From

this voltage, we can calculate the temperature

using the characteristic values for our NTC. Our

program is essentially:

while true: clear()

adcValue = readADC(IN06, 100)

T = calculateTfromA(adcValue)

drawText(10,90, "T = " + T + "°C")

update()

delay(1000)

In an endless loop, the program clears the

display with clear(), then reads ...