I have a problem with my project, and I hope that you will help me!
The project it's a little more bigger, but I'm at the beginning. So, I have connected to Arduino a GPRS SHIELD SIM900, a PIR sensor, a buzzer, a vibration sensor and a led. All works fine, until I send a SMS to the SIM900, when I do that, all my sensors go crazy, the PIR will say that he detect motion, the buzzer will begin, my led will be on, and the vibration sensor will tell me that he detect vibration. All the sensors have brick, so I don't have external resistors.
But, if I don't send any SMS, all sensors work fine, and they detect motion, vibration, etc when it is.
It seems that when I send a SMS for Arduino through SIM900, it jam all the sensors.
The GPRS shield can draw up to 2 amperes when transmitting. I imagine that you are trying to power it from the Arduino, which can't provide nearly enough current, and malfunctions.
Use a separate power supply for the GPRS module, being sure to connect the grounds together.
Yes, this is an indequate power supply issue almost certainly. However it might also be due
to RF interference if the GSM antenna is very poorly placed.
We already provided the GSM shield an extra external power supply but, whenever we send sms to the gsm shield it does what it should do. To switch on and off the led but THE problem is before it switches the led it makes the pir go high and triggers to send sms motion.
Also, when we try to send a call to the gsm shield, the pir sensor also get's activated and sends sms motion.
