Introduction: Mobile Intercom With A6 Module and Arduino

Picture of Mobile Intercom With A6 Module and Arduino

In this instructable I show you how I made a intercom using a GSM module.

If you press the big button, the programmed number is called. The call is ended after a programmed time, or by pressing the hangup button.

Components I used:


Arduino pro mini:

A6 module:



Tactile switch, any, like:

Step 1: Tweak the A6 Module

Picture of Tweak the A6 Module

The get sound of the phone call, i needed to tweak the connections of the module on the PCB. On the PCB, the EAR_L and EAR_R are connected to the pins, but I needed the REC- and REC+ connections.

So, I cut the wiring on the PCB and made connections directly from the REC- and REC+ connectors of the module to the pins which previously had the EAR connections

Step 2: Program the Arduino Pro Mini

Attached is the program I used, my program was inspired by Saravanan AL:

Pin 6 and 7 are both pulled up to 5V.

If the button connected to pin 7 is pressed, the programmed number is called

If the button connected to pin 6 is pressed, the "ATH" command hangs up.

Step 3: Connect All to a PCB

Picture of Connect All to a PCB

Connect all components to a standard PCB (30 x 70 mm).

The Arduino pro mini also gets a switch to the reset (RST, pulled up by 10k to VCC) pin, to reset the Arduino.

Step 4: Design and Print a Box

In 123D design a designed a box for the intercom. See attached STL files.

The files were printed on a Wanhao Duplicator i3 in Wanhao silver PLA. The box was printed with a 0.8 mm nozzle, the top with a 0.6 nozzle.

Step 5: Add All Together

Picture of Add All Together

Finally screw all together and glue in the tactile buttons. The speaker is glued to the top of the box.

Connect to a 5V phone charger as power supply and you are finished!


mahio4u (author)2017-10-12

Nice tutorial. I have an issue with my A6 MODEM. It shows creg:3 when it boots, but i can not communicate with it. if i dial the line, it shows RING on the terminal, but when I send AT commands, there is no response. What could be the cause? please help, as it is for my final year project. Thanks.

Wim3d (author)mahio4u2017-10-12

Please check the A6 instructions in:

It seems to me that Creg:3 means that registration to the network is denied.

How do you try to communicate? Via an arduino? Hardware or software serial?

sanghanis (author)2017-07-26

what sim card use in a6 gsm

Wim3d (author)sanghanis2017-07-27

A mini SIM card

DIY Hacks and How Tos (author)2017-07-16

Cool intercom system. I wish that I had something like this set up for my workshop.

Thanks. I made this one for my brother to use with his fruit vending machine, for a customer who needs help or needs some change.

About This Instructable




Bio: I like to combine electronics like Arduino's, ESP8266 etc with 3D designing and 3D printing.
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