In this article, I show how to code by using Arduino and SIM90A to turn of or turn on relay with mobile phone SMS.
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Step 1: Hardware
1 Arduino pro mini Module
1 sim900A mini module1 USB UART CP2102 module for programming to Arduino1 Relay module1 Testboard
Step 2: Library for Arduino
You can download from here
Uncompress and copy to libraries folder of Arduino IDE
Step 3: Pins of SIM900A
Power: using adapter 5v / 2A for Sim900A
I using SIM900A has 5VDC power
Step 4: CONNECT ARDUINO TO SIM900A
Sim900A RX pin connect to Arduino TX pin (pin 3). See schema below to connect.
Sim900A TX pin connect to Arduino
RX pin (Pin 2) Sim900A GND pin connect to Arduino GND pin
Connect power 5VDC to 2 module
Relay 1 connect to pin 7 of Arduino
Relay 2 connect to pin 7 of Arduino
Step 5: Connect CP2102 to Arduino
Connect pins follow in image
Step 6: Source Code
Read source code for detail.
This is new version with changes
1. I using number in simcard and read it to memory
2. To check money account, please replace this line in checkTK function
with your country info
You can edit and free share
Step 7: VIDEO DEMO
Vietnamese in this clip and English translation