DIY In House Wireless Walkie Talkie - Voice Intercom Adventure

UPDATE: Github code for M5Atom Walkie Talkie

I was looking for a DIY in house voice intercom system. If you have a teenager living with you in a 3 levels house, you should have strong lungs and a sergeant voice to call him shouting for dinner or to tell him take out the trash; otherwise a hide and seek takes place inside the house to find him. Instead of calling him on the cellphone which he will never answer, i tried to find an intercom project to install in each room. Unfortunately alexa, google home mini etc are not in my native language and therefore are not sold in my country.

Searching on the internet, i came upon ESP32 Walkie Talkie by atomic14, and that was exactly what i was looking for. Instead of using ESP32, i decide to use M5StickC which has a microphone built in, 3 buttons and a nice LCD screen with battery. The only missing part was speaker and amplifier. Changed atomic14’s code accordingly and tried it; it worked, however the speaker was so tiny it acts as a buzzer instead of a speaker. Also, the microphone was so buried inside that you have to stick the M5 to your mouth for your voice to be recognized. So i used to M5StickC and SPK HAT in my other Earthquake Sensor Project.

I quickly came into senses to understand that using an i2s microphone (INMP441) and an i2s amplifier (MAX98357) was required so i bought 2 sets of each. Instead of using a regular ESP32, i decided to use the marvelous M5Atom ESP32 because of its size. So the prototype is like this:

Using longer jumper cables spend too much of my time; it creates enormous amount of noise on the microphone; so i needed to shorten all of it. I guess using a PCB like atomic14 and some capacitors to make a stable feed will be a lot better.

The prototypes were ready to test:

Changing the code was the hardest part; since this was my first time dealing with i2s and UDP transport. But after struggling a lot, i managed to make it work; and the performance is quite good. The good thing is you can either use UDP on WiFi or ESPNow. I decided to use ESPNow for protocol in order not to put an additional UDP stress on the local WiFi, ESPNow communicates directly to each other without usig WiFi (as far as i understand :grinning:)

The only thing left is after my tests, i decided to go with larger speakers since this kind of tiny speaker sounds works but are not enough.

So, next steps:

  1. Select high performance (louder) small size speakers
  2. Prepare a PCB which also stabilizes power for less noise
  3. Prepare a 3D print enclosure
  4. Publish the code on github (It is a mess now, have to tidy it up)
  5. Home Assistant interface (Possibilities are endless)
  6. Batteries ?

All in all it works perfectly. I might need assistance especially on 2 and 3, Stabilizing power and prepare a PCB and also preparing a 3d Print enclosure. If any of you guys can help, i appreciate.


Looks like you’re using a Mac…

Homepod Mini has intercom support. Easy solve if your time is better spent elsewhere.

Thanks @HVR88 , unfortunately homepod is not being sold in my country, nor it supports my native language. Comparingly, this is a lot more cheaper and you can also connect it to HA directly.

He won’t answer the phone, but will pickup a walkie talkie

Here is the github code for M5Atom Walkie Talkie if anyone interested…

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Are you not familiar with how a walkie talkie or intercom work? :slight_smile: You don’t need to pick them up.

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Took all components inside an M5Stack Proto Board Kit. Now it looks more like a real walkie talkie:


I would like to try what you did and if it works for me, I will make lots of them. I have 2 extra M5Stack Atom Lite (bought a few of them for HA Bluetooth Proxy). I can find on AliExpress all the parts you listed (Atom HUB Proto Board Kit, INMP441 omnidirectional i2s MEMS microphone, and MAX98357 i2s amplifier) but not the speaker. I am not sure about its specs (diameter, ohm, watt, whether there should be holes in 4 corners for mounting and the distance between them).

  1. Can you provide a link to purchase your speaker or equivalent specs (AliExpress preferable)?

As to battery, I saw this M5Stack TailBat on AliExpress.

Just found this amazing item on AliExpress. Check it out! US $7.60 | M5Stack Official ATOM TailBat - Battery Accessory for ATOM

2.,Not sure if this battery will fit on Atom HUB Proto Board Kit and if it will work with your setup.

I am a HA beginner. Just learned how to add IOT devices into HA (Zigbee2MQTT, BLE, Wifi devices) and basic automation using UI. Do not know about YAML and coding.

  1. Wonder if you can elaborate more on how one can go about and assemble all the parts you listed and install the codes. A Youtube VDO would be perfect.

Help on any or all of the above would be greatly appreciated.