Using Opto22 Modules with a Propeller

Al Booth

Has anyone used Opto22 Modules with a Propeller? I need to, and plan to drive the output module with a 2N2222 from a Propeller pin. And hope to directly connect the input module to another pin. I am a little concerned that using 3.3 volts on the input module might be too low. Any comments, or suggestions?

Thanks,
Al

JonnyMac

Some of those modules are rated that low, but for about a quarter you can add a resistor (limiter into base) and transistor to switch 5v or higher into the module. Using an NPN is easiest, I think, so you'd switch the negative side of the control input with the collector of the transistor.

If you're going to be controlling more than a few of these relays you can plunk a ULN2x03 in between the Propeller and the relays.

Al Booth

Thanks for the reply, Jon. I do have the 5 volt versions of the modules (IDC5 and ODC5). Since I only have 1 of each in my circuit, I'll stay with the transistor driver. I was aware of the ULN2x03 line of parts, but it would be overkill since I only need 1 or 2 drivers.

localroger

The specs say the 5V modules switch on at 2.8V and off below 1V. I would just drive them straight fromthe prop pin. First google hit: http://tomscarff.110mb.com/midi_12_out_4_in/OPTO22_Std_Dig_DC_Outputs_data_sheet.pdf

For inputs, if you have 5V available just feed the opto 5V and run the input output line to the prop pin thru a 10k resistor.

PJAllen

Yes, if that PDF is it, there's a pic of the equiv ckts and the input is just an LED and a resistor, in series (refer esp. R_sub_C), > 2.5V, direct driveable (within reason.)

Post Edit -- Dispel all doubt, get the ammeter out.