Ok, I'll keep it short. I need a [u]device to switch ON/OFF a 24V low current (100mA - 250mA) load[/u] using the Arduino. Someone suggested that I use an SSR, but they're expensive and also switch AC current. I need this only for a full DC line. My idea currently is to use an optocoupler because there are 2 supplies, 5V powering the arduino and 24V powering something else. I cannot use the 24V to power the arduino because it's a very low current (1A) compared to the 5V (10A) supply I'm using to power several other devices. So, optocoupler is it then. On one end I'm using the 5V signal through a resistor to power the Opto, since it's technically an LED switching ON. The other end is where I'm stuck. [u]This is what I'm following -[/u] Opto side: 5V --- resistor --- opto LED (power) --- GND Switching side: 24V --- resistor --- opto --- 24V Input The 24V device here takes 24V inputs as signals. So when the arduino pulses a 5V signal, the 24V line gets switched on. So, it's basically a 5V solid state relay, but the voltage is 5V to actuate and 24V Load. The method I'm using looks right 8) , opto side resistor to to limit current into LED, switching side resistor to limit current entering photo-detector. But I'm sure there are loopholes somewhere.
Help out People !!!! =(