Firstly a big thank you for the excellent work of erocm1231 and I used his program guide to flash the Sonoff Basic and that can be found here:
So I had various problems using the Sonoff 5V latching module mostly around simulating a push button (non-latching) event and I decided to see if I could convert the 220v AC Sonoff basic to a low voltage DC switch and it turned out to be easier than expected.
Three simple steps :
1 Flash the Sonoff Basic using erocm1231 step by step guide and set it up on Smartthings.
2 Solder some wire to the capacitor C9 and use a 5.5V power supply to power the board. I added a stripped down 12V USB charger to get 12V dc to 5.5v dc as my gate unit is 12v.
I removed the screw terminals to cut down the size (optional) and soldered a wire to the the input and output making a push to make switch.
3 Add a rule in Smartthings that if the Sonoff switch is on then turn it off. I used Smartrules for this and it switches off after about half of a second. So when I send an ‘on’ command it goes off automatically. This simulates a button press.