Hi, just received this LM393 based soil moisture sensor. For one of the application I would like to save the cost of a microcontroller and just trigger a pump with the comparator. The pump works at 12V, so thought to turn everything up to 12V. I risked the leds being burned, the digital out led burned, but the problem is that the comparator also seems not to work anymore. The reference voltage is set for instance to 7V, but whatsoever resistence (0 to infinit) I apply to the input of the sensor circuitry, the digital output stays on 12V as if the comparator would have been burned.
On the spec I understand that lm393 can run up to 36V. What can have went wrong. (I desoldered the burned out led on the output, so at the moment there is no charg on the output)
Pumps require far, far more current than typical digital or analog ICs (including Arduino) can deliver, so your idea won't work. Also, motors create electrical noise that is very hazardous to just about any electronic circuitry, so you've probably destroyed the LM393 as well. Use a relay or dedicated motor driver circuit to control the motor.
indeed, it was not clear, but did not use the engine on the output of the LM393, nor was I intending to do so. just with the normal led and resistor from the circuit and after I burned the led, I soldered a simple 2k resistor.
Will use later an n channel mosfet to drive the engine and will apply the voltage of the lm393 output to the gate.
BTW: what is the cheapest N channel mosfet on ebay that will be able to provide 1A at 12V?