Hello,
After assembling the MK125 kit it doesn’t do what I was expecting.
My expectation was: when it’s dark and the relay is off then when it becomes light the relay is switched on.
I have checked and double checked the parts and their position and polarity and checked all the soldering to be ok.
I have recorded a video to show you what happens: youtu.be/YYnISF6R3HQ
What you can see in the video is that the kit is powered off. The trimmer RV1 is fully counterclockwise. I power on the kit and slowly rotate the trimmer clockwise until the led is on and the relay clicks.
I then cover the LDR completely (making it dark) and I would expect the led and relay to switch off. But nothing happens.
Measure between GND and pin 13: should be adjustable between 0 and the power supply voltage minus a diode drop.
If not, check RV1 path.
Measure between GND and pin 12: voltage should vary a couple of volts between dark and light.
If not, check R1, LDR, R6, D2, R5, R4, C3 path.
Measure between GND and pin 13: should be adjustable between 0 and the power supply voltage minus a diode drop.
Works fine
Measure between GND and pin 12: voltage should vary a couple of volts between dark and light.
It goes up do about 8v and then drops to 0 when dark.
I have checked the placement of the named parts and they all seem to be OK.
If both are OK, swap LM324
Can try that, but which one do I need? There’s a few in the web shop where I usually buy parts.
I found the same manufacturer: ST MicroElectronics
But then there is choice between four types, does it matter which one or will each LM324N work?
Greetings,
Rob
