Step 1: Test with Xenon and a relay.
My old remote to garage was broken. So I made a small board with a relay. Then hook it up with a Xenon from Particle. However the Xenon by default is used for Mesh network. So I have to flashed a UF2 bootloader to it. Some script in CircuitPython written to bring up the BLE to test with my phone.
Step2: integrate the BLE module and relays into one board
This is an easy change because both module and the relay circuits are tested in Step1. Everything works as expected. The middle button at the top is not used.