Anyone know of a ciruit, with or with out the Arduino unit, that can detect voltages between 5 and 12 volts, and only output if 12 volts is detected.
Basicly i have a wireless device that has an output that varies in voltages, The manufacturer says it will be floating voltage when idle, and 12volts in alarm. I tested with my meter, 5.5 volts and 12.8 volts. If i attach a 12volt relay directly to the circuit, it holds down the device and wont allow it to operate properly. Im thinking a Transistor is the answer, but im not sure on detecting only 12 volts. Any one have an idea i can try???
Is it possible to use a voltage divider with a relay directly (without Arduino), i need to Minimize the circuit and size of circuit. Thanks for any suggestions.
Is it possible to use a voltage divider with a relay directly (without Arduino)
No, but if that's all that needs to be done a transistor should work.
Transistors aren't my forte but the signal should be able to drive one easily enough.
In general though use a resistor from your device to the base of an NPN, another pulling the base to GND, collector to the relay coil -, emitter to GND, coil + to 12v and a diode across the coil.
But it will depend on the ability of your device to drive something, Do you have a data sheet.
There are many examples on the web an din the Arduino playground I think.
Yes you can get a transistor to do this. You need a potential divider to reduce the 5V to just less than 0.7V. Feed that into the base of a transistor, put the emitter to ground and the collector to one end of the relay coil. Put the other end of the relay coil to the positive of your supply.