Bluetooth/ sim900


I need help trying to send information via Bluetooth to a sim900.
i have 6 Bluetooth hc-05 module’s, I would like for them to text me when they trigger.

I’m not sure how to achieve this!!!
Please if I could get some guidance
It’s would be much appreciated

Thank you

BT HC-05 modules aside....

have you gotten the SIM900 (link to exact board you have/are using please) to work with any test examples?

Where are you located (geographically).. in the US?

Do you have a SIM card dedicated for this SMS usage?


Thanks for the reply.

I want to Kuman SIMCOM SIM900 from Amazon

I'm also located in California, US
And I also have a Sim Card for the SMS

SIM aside, you might find six blueteeth a lot to hang off one Arduino. If this is some sort of proximity system, you might find you can do this by programming the STATE pins and reading them as digital signals.

Thanks for everyone's comments there helpful, but I what I would like to achieve is for a Bluetooth device to connect to the SIM900 so I could get a text.. If one module is a sender and one is a recover could it connect to a Arduino uno or to the sim900 directly..

Same Question:

Have you gotten the GSM module to work 'out of the box' with any of the stock examples?

Put any/all bluetooth stuff aside for now... and ensure you have a working GSM/SIM 900 module.

Lets take a step back here for a second.

1.) You have '6' BT modules... right?

  • connected to what?
  • have you ensured these are working at all? (have you been able to receive any BT (serial) data on an end deivce?) (ie: your andriod cell phone perhaps? to check if you are even sedning data properly?

2.) You have this SIM900/GSM module... connected to what?

In general terms.. you need to have your Arduino with BT modules connected (although if you have 6 connected to the same Arduino..... I'm failing to grasp WHY? instead of just using one?) If these BT modules are each connected to its own Arduino and are placed around an specific area, that makes more send.. but not 6 connected to 1 Arduino board?

The arduino will check some sort of event (temp/sensor value) and then use the BT module to send this serial data out THROUGH the sedning BT module..

over to another BT module connected to its OWN Arduino... where it will receive this serial data from BT/Arduino set#1.. and parse it.. based on the data received, it will then send some AT commands to the GSM/SIM 900 connected shield to TEXT you.

So in a trimmed/paired down project scenario..

you need:

  • BT module connected to Arduino (for sending your 'data')

  • BT module connected to Arduino that has the SIM900/GSM shield attached (for receiving your data from the above BT/Arduino pair)... and in turn will send a TEXT to your phone.