Remote gates opener (Arduino+SIM800+TF433Mhz )

Wireless & IoT
1

Hello everyone, i am working on project to make my yard gates to open on phone call. When a call is received, the phone number is compared against an authorized phonebook, and if the number is in the list, a transmitter sends signal to my gates.

The project as it is now is functional, but I stuck with very strange problem and don’t know what to do.

The problem is that transmitter properly sends signal only when I hold all three transmitter wires in my fingers. If I let wires hang or put on table or other it’s not working… Any help for this problem ? :slight_smile:

I think maybe it’s problem with noise, ground connection or something…

Sorry for my bad English, but I hope you understood me :slight_smile:

I’m using:

Arduino UNO board

SIM800c shield for Arduino (from AliExpress)

433Mhz transmitter

2

Sounds like a bad connection, or an antenna problem. You need at the very least a 1/4 wave, 17 cm piece of straight wire for the antenna.

However, by far the best but simple antenna for those radios is a balanced dipole, about 34 cm from tip to tip for 434 MHz, as shown below. I get 300 meters range (line of sight) with this setup.

Connect the transmitter or receiver ANT terminal to one inner end, transmitter or receiver GND to the other with short leads.