A small Arduino library for GSM modules, that just works.

If you like TinyGSM - give it a star, or fork it and contribute!

You can also join our chat:

Arduino Client interface support

This library is easy to integrate with lots of sketches, which use Ethernet or WiFi.
PubSubClient (MQTT), Blynk, HTTP Client and File Download examples are provided.

TinyGSM is tiny

The complete WebClient example for Arduino Uno (via Software Serial) takes little resources:

Sketch uses 14094 bytes (43%) of program storage space. Maximum is 32256 bytes.
Global variables use 625 bytes (30%) of dynamic memory, leaving 1423 bytes for local variables. Maximum is 2048 bytes.

Arduino GSM library uses 15868 bytes (49%) of Flash and 1113 bytes (54%) of RAM in a similar scenario.
TinyGSM also pulls data gently from the modem (whenever possible), so it can operate on very little RAM.
Now, you have more space for your experiments.

Features

Feature \ Modem	SIM8xx	U201	A6/A7/A20	M590	ESP8266	XBee
Data connections
TCP (HTTP, MQTT, Blynk, ...)	✔	✔	✔	✔	✔	✔
UDP	◌	◌				◌
SSL/TLS (HTTPS)	✔¹	✔	🅧	🅧	✔¹	✔¹
USSD
Sending USSD requests	✔		✔	✔	🅧
Decoding 7,8,16-bit response	✔		✔	✔	🅧
SMS
Sending	✔		✔	✔	🅧	✔
Sending Unicode	✔		◌	🅧	🅧
Reading					🅧
Incoming message event				?	🅧
Calls
Dial, hangup	✔		✔	🅧	🅧	🅧
Receiving calls	✔		✔	🅧	🅧	🅧
Incoming event (RING)	◌		◌	🅧	🅧	🅧
DTMF sending	✔		✔	🅧	🅧	🅧
DTMF decoding	◌		🅧	🅧	🅧	🅧
Location
GSM location service	✔	✔	🅧	🅧	🅧	✔
GPS/GNSS	✔¹	🅧	◌¹	🅧	🅧	🅧

✔ - implemented  ◌ - planned  🅧 - not available on this modem
¹ - only some device models or firmware revisions have this feature (SIM8xx R14.18, A7, etc.)

Supported modems

• SIMCom SIM800 series (SIM800A, SIM800C, SIM800L, SIM800H, SIM808, SIM868)
• SIMCom SIM900 series (SIM900A, SIM900D, SIM908, SIM968)
• AI-Thinker A6, A6C, A7, A20
• U-blox SARA U201 (alpha)
• ESP8266 (AT commands interface, similar to GSM modems)
• Digi XBee WiFi and Cellular (using XBee command mode)
• Neoway M590

Supported boards/modules

• Arduino MKR GSM 1400 (alpha)
• GPRSbee
• Microduino GSM
• Adafruit FONA (Mini Cellular GSM Breakout)
• Adafruit FONA 800/808 Shield
• ... other modules, based on supported modems

More modems may be supported later:

• Quectel M10, M95, UG95
• SIMCom SIM5320, SIM5216
• Telit GL865
• ZTE MG2639
• Hi-Link HLK-RM04

Watch this repo for new updates! And of course, contributions are welcome ;)

Donation

If you have found TinyGSM to be useful in your work, research or company, please consider making a donation to the project commensurate with your resources. Any amount helps!
All donations will be used strictly to fund the development of TinyGSM:

• Covering cellular network expences
• Buying new hardware and modems for integration
• Bounty Budget (to reward other developers for their contributions)
• Implementing new features
• Quality Assurance

Getting Started

1. Using your phone: - Disable PIN code on the SIM card - Check your ballance - Check that APN,User,Pass are correct and you have internet
2. Ensure the SIM card is correctly inserted into the module
3. Provide a good, stable power supply (up to 2A and specific voltage according to your module documentation)
4. Check if serial connection is working (Hardware Serial is recommended)
   Send an AT command using this sketch
5. Check if GSM antenna is attached

How does it work?

Many GSM modems, WiFi and radio modules can be controlled by sending AT commands over Serial.
TinyGSM knows which commands to send, and how to handle AT responses, and wraps that into standard Arduino Client interface.

API Reference

For GPRS data streams, this library provides the standard Arduino Client interface.
For additional functions, please refer to this example sketch

Troubleshooting

SoftwareSerial problems

When using SoftwareSerial (on Uno, Nano, etc), the speed 115200 may not work.
Try selecting 57600, 38400, or even lower - the one that works best for you.
Be sure to set correct TX/RX pins in the sketch. Please note that not every Arduino pin can serve as TX or RX pin.
Read more about SoftSerial options and configuration here and here.

Diagnostics sketch

Use this sketch to diagnose your SIM card and GPRS connection:
File -> Examples -> TynyGSM -> tools -> Diagnostics

Broken initial configuration

Sometimes (especially if you played with AT comands), your module configuration may become invalid.
This may result in problems such as:

• Can't connect to the GPRS network
• Can't connect to the server
• Sent/recieved data contains invalid bytes
• etc.

To return module to Factory Defaults, use this sketch:
File -> Examples -> TynyGSM -> tools -> FactoryReset

---

License

This project is released under The GNU Lesser General Public License (LGPL-3.0)