I am looking to control three SSR's (datasheet<http://www.fotek.com.tw/pdf/etc_34.pdf>). I have tried directly hooking them up to the BB, but only one of them will actually switch when the GPIO pin is set to high. The datasheet says the trigger current is 7.5mA / 12 V (max 3-32V). I obviously need to augment the voltage and/or current, so I ordered a ULN2003. This is spec'd to do a max 500mA current (per driver) and 50V. I have tried to get a little basic understanding of the darlington array, but I can't figure out a few things:
1. For these SSRs' input voltage, I can't go over 32V. Does the input voltage on the ULN2003 match the output voltage? 2. If I were able to use the BB's 3.3V pin as the input voltage, would there be enough current to trigger the SSR? 3. How many channels on the ULN could I power if I used the 3.3V on the BB? As I understand, the GPIO are not for sourcing current. Another option (what makes the most sense to me) is using the BB's 5V power supply for both the BB and the ULN2003. I don't know where that puts the output voltage (question #1). The BBB docs suggest 2A supply if you are running a USB peripheral. I have a WiFi USB dongle being used. The supply is rated at 2A. According to my Kill-a-watt, I don't see a draw of over 100mA. It draws 70-80mA at idle/load. I'm not sure if you can use the kill-a-watt as the amperage draw though? Thanks -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
