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istatrol [2016/03/25 16:41] – [RADIATOR_RESPONSE_TIME] Traumflugistatrol [2016/03/26 15:17] – [Temperature Sensors] Clarification. Traumflug
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 {{ :istatrol:istatrol_thermistor_readout.png?direct&300|Very coarsely measured readout of the developers thermistor.}} {{ :istatrol:istatrol_thermistor_readout.png?direct&300|Very coarsely measured readout of the developers thermistor.}}
  
-For the technical: ATtinys feature no Analog Digital Converter (ADC). But there is [[https://github.com/Traumflug/ISTAtrol/raw/master/data%20sheets/AVR400.pdf|Atmel Application Note AVR400]], outlining how to get analog readouts by using the Analog Comparator (ACO) anyways. Essentially, a capacitor is loaded starting at time zero, then the time measured (with 16-bit Timer 1) how long it takes to reach a constant comparison voltage. As the loading current goes through the thermistor, higher thermistor resistance ( = lower temperature) leads to a longer loading time and vice versa. This implementation is actually simpler than one using an ADC.+For the technical: ATtinys feature no Analog Digital Converter (ADC). But there is [[https://github.com/Traumflug/ISTAtrol/raw/master/data%20sheets/AVR400.pdf|Atmel Application Note AVR400]], outlining how to get analog readouts by using the Analog Comparator (ACO) anyways. Essentially, a capacitor is loaded starting at time zero, then the time this capacitor takes to reach the same voltage as a constant comparison voltage measured (with 16-bit Timer 1). As the capacitor loading current goes through the thermistor, higher thermistor resistance ( = lower temperature) leads to a longer loading time and vice versa. This implementation is actually simpler than one using an ADC.
  
 As one can see by the coarse measurements done, this is linear enough for our purposes. The recorded pretty hefty hysteresis isn't a property of the thermistor or the ISTAtrol, it's an artefact of the measurement procedure. As one can see by the coarse measurements done, this is linear enough for our purposes. The recorded pretty hefty hysteresis isn't a property of the thermistor or the ISTAtrol, it's an artefact of the measurement procedure.
istatrol.txt · Last modified: 2018/05/27 16:10 (external edit)