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Temperature controller
Temperature controller is a device, which switches on and off different systems,
according to the temperature's changes. This prototype presented on Fig.1 is based on an analog comparator LM324.
The main unit is a standard NTC based thermostat (Velleman-kit MK138) with low voltage relay output.
Unfortunately MK138 unit can not function without a stable supply (very important for correct measurement) and can not control 220V devices.
The box presented on the picture consists of several blocks integrated together:
- stable 1 A, 12 V supply
- thermostat unit
- output relays for low voltage12 or 244V ( 3A)
- output relays for 220V (0.6A)
The thermostat is usable for controlling temperature (5 to 30 degrees Celsius)
using low consumption 220V (0.6A max)or low voltage 12V (1A max)devices. It can be used also as frost alarm due to possibility to capture low temperature (5 degrees Celsium max).
The histeresis can be calibrated to several degrees to prevent the output of oscilation.
Fig.1 Thermostat controller: the detector is outside the unit connected with wellow and black cable.
The size of the thermostat is 128mm (L),63mm(W),46mm (D). The black cables presented on Fig.1
are 220V cables ( 1 input and 2 outputs).
The consumption of the controller is around 100mA depending of the mode ( relays on/off). A small led diode
can be used as indicator for on/off.
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