Hi,
I found this beatiful old clock and found out that it's a slave clock (driven by 12 volt pulses, reversing polarity on the odd minutes). I figured arduino could to this with two optocouplers (one for odd numbers and one for even numbers). The clock is driven by an magnet and coil, the coil resistance is 1919 Ohm. Problem; (i only have a simple multimeter) when the magnet is pulsed the current peaks to 10A? This is when i wire the coil directly to my PSU, is this the problem?
How did you come up with that value of 10A? The maximum current for dc pulse in a inductor is U/R which would mean 6mA.
A H-bridge might do the job of driving the coil with both polarities
Ok, So i have this L293DNE left from an stepper driver which could'nt deliver enough current for the steppers i had. Im not experienced with making my own circuits, i always used ready to use modules.
Is this way of wiring correct?
1 - to an arduino pin
2 - to an arduino pin
7 - to an arduino pin
4, 5 - arduino ground
3, 6 - to clock coil
16 - 5V (from arduino)
12, 13 - Ground power supply
8 - Power supply
Pin numbers taken from Texas Instruments 0xt5w1akzx8dd88ewqdxi35wa9py datasheet pdf
10A definitely indicates a short circuit somewhere (assuming you're using the multmeter correctly). The metal frame may be connected to one of the relay coil terminals for instance.