I don’t think it is possible | Projects › Projects › how to made relay on/off using gsm sms? › I don’t think it is possible January 11, 2013 at 5:16 pm #8933 AJISH ALFREDParticipant I don’t think it is possible without microcontroller. But there are certain examples by which you can control the relays by making a call to the gsm modem.
