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Send an SMS with the A7670 LTE module

Embedded (ESP32) · Intermediate · about 20 minutes · part of Zen’s Electronics Design Mastery

Cellular modules are driven by AT commands over a serial port. Press the button and the ESP32 tells the A7670 to send a text message: the basis of alarms and trackers where there is no Wi-Fi.

Send an SMS with the A7670 LTE module: the circuit on the simulator's bench

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How it works

AT+CMGF=1 selects text mode; AT+CMGS="number" then the message and Ctrl-Z sends it. Each command answers OK or ERROR.

The modem draws up to 2 A in bursts while transmitting, which is why it gets its own buck converter.

Try it on the bench

  1. Wait for “Press the button”, then click the button and watch the AT exchange in the serial monitor.
  2. Select the A7670 and set the signal to poor: sending takes longer or fails.

Parts on the bench

In the course

Zen’s Electronics Design Mastery, module “Microcontrollers & Embedded”.

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