In my previous post, I shared how I was adding WiFi control to open my gate remotely using an ESP01S board and a Relay module. While the setup was working perfectly with Home Assistant integration, the biggest issue I faced was its power consumption. The battery would last only two days, which made it a hassle to recharge every other day. This led me to explore other solutions to power the system for longer durations.

First try: ESP Deep sleep

After some research, I came across the concept of ESP’s deep sleep mode that allowed the ESP board to save power, by shutting down unused components and putting it in a “Deep sleep” mode. I had to solder the RESET pin with ESP8266’s GND output to use this feature on the ESP01S board.

This fix increased the battery life to around 3-4 days, but it was still not enough to make it feasible for daily use. It became a pain to recharge the battery every few days, so I needed a better solution.

Second try: Bell power lines

I decided to open up the intercom, and the electric box behind, to find an alternative power source. And I found electric wires that powered the door bell! But sadly, the voltage (15V) was too high so that it could fry the ESP board. To solve this issue, I tried a DC/DC converter that could convert 15V to 5V, it worked but it was too big to fit inside the electric box.

Final solution: Zigbee 32V relay

It wasn’t long until I found another solution – a Zigbee relay that accepted 7-32V input. This awesome relay had many features, including an IR receiver and pulse mode (which turns on and then off after 1 second). The relay also supported Zigbee Router mode, which could help to expand my Zigbee network.
Using the Zigbee relay was very easy. I just needed to plug the NO and COM ports with the intercom button and the 15V power lines into GND (-) and VCC (+). Home Assistant’s ZHA detected it right away, making the setup process quick and easy.
I also set up the IR receiver with an unused button on my TV remote. This feature came in handy as I could control the gate from anywhere in the room, even without my phone.
Using the Zigbee relay to power the intercom system was a game-changer. It eliminated the hassle of recharging the battery every other day and provided a permanent power source. Also the IR receiver and pulse mode made it even more convenient to use. I couldn’t put the relay inside the intercom, but its case doesn’t look bad outside anyway.

Extra: Buzzer detection

Now, what if I could attach a vibration sensor to the intercom buzzer to alert me whenever someone rings the gate bell? It would be so useful, if I could know if someone has come to visit when I’m not at home.
With some other research, I’ve found that there are many different types of vibration sensors available on the market, but I needed one that was small enough to fit inside the intercom and could communicate with my Home assistant setup easily. And that’s when I discovered the Aqara Zigbee vibration sensor which ticks all the boxes. It’s so compact (I removed the cover, keep only the board and battery), has a long battery life, and uses the same Zigbee protocol as my existing devices, making it a perfect match for my setup.
I sticked the vibration sensor into the intercom buzzer, making sure it was securely attached and wouldn’t interfere with the intercom’s functionality. Then I wrote a simple Home assistant automation to send me a push notification whenever the sensor detects any vibration. In this way, even if I’m away from home, or if I miss the buzzer sound, I still could know when someone is at my gate.

The combination of the Zigbee relay and the vibration sensor proves to be a best solution, allowing me to remotely control the gate and receive alerts whenever someone rings the bell. So happy!