Hacking my garage door remote

Other Hardware Device Hacking
1

I'm hacking my garage door opener and need a little assistance on the sketch to use a 433MHz RF transmitter to send the correct code to open the door

My opener has 2 buttons. Each button has a series of 10 dip switches that I can set to change the transmitted code. I've already captured the transmitted code and can calculate any code based on the dip switches
The code is 5 bytes long and each switch controls half a byte. code for ON is 1110 and code for OFF is 1000.

I know the exact freq is 466.975MHz and each cycle is 0.5ms and one button produces a 1 wave length per cycle and the other button produces 4 wave lengths per cycle.

As an example:
DIP: ON OFF ON OFF ON OFF ON ON OFF OFF
BIN: 1110 1000 1110 1000 1110 1000 1110 1110 1000 1000
HEX: 0xE 0x8 0xE 0x8 0xE 0x8 0xE 0xE 0x8 0x8
CODE: 0xE8, 0xE8, 0xE8, 0xEE, 0x88

I am using an Arduino Nano Every and have a 433Mhz Transmitter with 3 pins (data, 5v, GND).
I setup an Arduino UNO as a test receiver with the matching 433MHz receiver with 4 pins.

So this is where I'm running into an issue:
I've tried using the "01_send" example sketch from rf433send (https://www.arduinolibraries.info/libraries/rf433send)
I can get it to transmit/send with all the example
byte data[] = { 0x03, 0x14, 0x15, 0x93 };

If I add a byte to the array I get an error: "rf433send.cpp:166: assertion failed, aborted."
byte data[] = { 0x03, 0x14, 0x15, 0x93, 0x16 }; // error

Secondly I've tried using the RadioHead Library (http://www.airspayce.com/mikem/arduino/RadioHead) "ask_transmitter" example
sketch. It throws an error when loaded on the Nano Every but does not throw an error if i try to load onto the UNO. I'm assuming this library does not Nano Every compatible. I want the transmitter to be on the Nano Every due to size
"Error compiling for board Arduino Nano Every."

The solution I'm looking for will transmit 5 bytes at 433.975MHz with a cycle of 0.5ms on an Arduino Nano Every.
Code 1 will have 1 wave length per cycle
Code 2 will transmit at 4 wavelengths per cycle

Here is an example of the signal

Capture
Capture1027×894 106 KB

2

And your using a 433Mhz transmitter ?

1 Like
3

That sounds like an ancient opener. If you look on your remote to see if the words SECURITY+ or Rolling Code can be found. If this is the case, your door opener has the built in rolling code technology. This indicates the code changes each time you cycle the door. Of course it must be on the correct frequency to work. How did you determine the exact freq is 466.975MHz?

4

It may be easier to replace the transmitter/receiver pair while retaining the rest of the garage door electronics. Alternatively, just add another receiver in parallel with the old one.
Choose a radio pair which is easier to hack if you can accept a lower security standard.

5

As does, any software that uses 328p series specific hardware timers.

6

The Pro Mini is about the same size as the Nano Every, and unlike the Nano Every, will run Uno code.

This tutorial is a good intro to hacking RF remotes, weather sensors, etc.

7

Screw all that. Wire a pair of NO relay contacts across the button normally used. Use an ESP for wifi -- done. No waveform analysis, and will work with any opener system. Buy a spare remote.

2 Likes
8

use an Arduino Nano Classic - not an Every instead. The Arduino Nano classic has the same controller like the UNO and about the size of the Nano Every

9

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