Send HTTPS request from SIM 7600x LTE Module

Kidd Tang
3 min readJun 27, 2021

Pre-requisite

  • Arduino with ESP32 board support (HOW?)
  • SIM7600 Modem Module
  • Installed two libraries — TinyGSM & SSLClient

Libraries used in this tutorial:

  1. vshymanskyy/TinyGSM — For GPRS/LTE and modem utilities
  2. govorox/SSLClient — Transparent SSL wrapper over existing transport object of a Client class

TinyGSM can be installed directly in the Arduino interface

SSLClient is not published and you need to install it manually (Here is the guide)

Codes are derived from the examples blow:

  1. TinyGSM — “All Functions” sample
  2. LilyGO-T-SIM7600X — “All Functions” sample
  3. SSLClient — “https_gsm_SIM7000” sample

How to obtain the CA cert

Run the command in your Git Bash, then look for the ROOT CERTIFICATE.

openssl s_client -showcerts -verify 5 -connect vsh.pp.ua:443 < /dev/null

Copy and paste into your Sublime Text / VS Code which can do the multi cursor and make it into certs.h like below:

add and \n” in between the content of each line

Connect to your Mobile Operator

Make sure you provide the correct credentials for you to connect your operator:

Explain the SSLClient Usage

This part is to set up the HTTP Client on top of the transport (TinyGSM) and presentation (SSL) layers

Then adding the Root CA Cert in the setup()

GET request

This is the part of the HTTPS GET request

You can get the full source code from here.

If you can see the logo, and obtain the 200 status code.

POST Request

Create a HTTPS Post Endpoint on Hookbin

Update the endpoint accordingly.

This is the part of the HTTPS POST request

You can get the full source code from here.

You can see the posted content, and obtain 200 status code.

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Kidd Tang

Full-stack web developer with electronic engineering background.