- Tue Mar 15, 2016 4:33 pm
#43251
The Sainsmart 2/4/8 channel relays http://www.sainsmart.com/sainsmart-rela ... ry-pi.html are opto-isolated and can be driven directly from 3v3 logic, see the following for details:
https://forum.pjrc.com/threads/26403-re ... elp-needed
https://arduino-info.wikispaces.com/ArduinoPower
Remove the VCC JD-VCC jumper so you can connect VCC to your 3v3 logic supply and JD-VCC to your 5V supply to energize the relay coils. Sainsmart also has a 16-channel board with 12V relays if that simplifies your design, don't know if they have a 12V version with fewer relays. Or buy a clone, lots of those available on the usual sites but not all are opto-isolated .
https://forum.pjrc.com/threads/26403-re ... elp-needed
https://arduino-info.wikispaces.com/ArduinoPower
Remove the VCC JD-VCC jumper so you can connect VCC to your 3v3 logic supply and JD-VCC to your 5V supply to energize the relay coils. Sainsmart also has a 16-channel board with 12V relays if that simplifies your design, don't know if they have a 12V version with fewer relays. Or buy a clone, lots of those available on the usual sites but not all are opto-isolated .
- Tue Mar 15, 2016 4:45 pm
#43253
Super cool. I have an 8 channel one of those left over. I didn't know it would do 3v3.
- Tue Mar 15, 2016 5:30 pm
#43260
OK, I tested my relay module using a standard dual rail breadboard power supply. I wired 5v to jd-vcc and ground to ground, 3.3v to vcc and grounded a relay terminal. The relay switched as expected. I measured amperage and see 40ma. I thought esp (huzzah datasheet) is limited to 12ma on gpio. Won't this burn out the huzzah?
Does sinking vs sourcing make a difference in power handling?
Does sinking vs sourcing make a difference in power handling?
