How to Use 5 Volt Relay Modules with Arduino and ESP8266
Taking a look at an opto isolated relay module and examining how it works:
-what does the control circuit look like?
-what is the rating on the relays, what voltages are required to use it?
-how can we use it with a PCF8574 gpio expander to use up to 8 relays per expander from the I2C bus if we don't have enough pins?
-can we run it at both 5V and 3.3V for modules that only support 3.3V? (both direct control and through the PCF8574)
-how simple is it to use a PCF8574 Arduino library to control the relays and read in buttons with the gpio expander?
-gotcha: making sure the relay module is properly configured for isolation if that is a desired use case. Just having opto isolators on board isn't all that's required
8 channel relay module Amazon affiliate link:
Amazon.com: https://amzn.to/2ldR8LB
Amazon.ca: https://amzn.to/2ldSEgL
Sketch and Schematic:
https://github.com/GadgetReboot/Ardui...
Datasheets:
http://www.ti.com/lit/ds/symlink/pcf8...
https://www.espressif.com/sites/defau...
Fritzing part for 4 relay module:
https://timgolisch.wordpress.com/2015...
Support the channel by using these affiliate links to check out Banggood's sale on Tools & Electronics this month (2021 4.07 - 4.18) :
Banggood hot brand tools https://bit.ly/3dSyO2l
Electronic Brand Sale https://bit.ly/2PHpeau
Creality 7th Anniversary Sale https://bit.ly/3d0fLUi
Note: If you make a purchase through my affiliate links, I will earn a small commission which helps the channel but doesn’t cost you anything extra.
Support me on Patreon: / gadgetreboot
#ElectronicsCreators