I'm going to use Arduino with some optocouplers to trigger the switches in some toys.
The toys will generely be low voltage (3-6 V). The way the switches in these toys usually work is that they either pull a pin on the embedded CPU down to ground or high to Vcc.
What i want to do, is have the Arduino controlled photocouplers do the switchng.
I happen to have a bunch of Sharp PC829 photocouplers :
Now as i read the the datasheet depending on the flow of the current through the phototransitor in the PC829 it can handle either 6V or 35V at 50mA
Vceo is the breakdown voltage from collector to emitter with the base open, where the collector is positive with respect to the emitter (this being an NPN transistor). Veco is the reverse breakdown voltage, i.e. from emitter to collector, where the emitter is positive WRT the collector. If the transistor is switching purely a resistive load, then we wouldn't normally expect any reverse potential from C to E, but this may occur with an inductive load (e.g. motors) in which case some sort of snubber circuit may be appropriate. If a toy's switch is just providing a signal to an MCU, then there should be no worries.