Raspberry pico - Tesla charging port opener

Tesla's charging port signal has been known for years. There are several projects about how to retransmit it, how to sample it for HackRF or other SDR's and how to retransmit it. However, I couldn't find a micropython implementation so I decided to have some fun.

The signal has simple ASK/OOK modulation with 2.5 kHz of sample rate, easy enough to attempt a microcontroller micropython implementation.

For more information about the Tesla's charging port signal and how to reverse engineer it:

• Original tweet
• HackRF based
• How to reverse engineer

How to use

Components

• Raspberry Pico
• 433.92 MHz transmitter for Europe (315 MHz for USA)
  • FS1000A - Meh, it may work or it may not, pray
  • STX882 - Much better option
• Antenna or 17 cm of wire [Optional]
• A way to connect everything

Assembly

1. Connect/solder the pins from the transmitter to the pico

   • VCC -> VBUS
   • GND -> GND
   • DATA -> GP0 (change the code if you prefer another pin)

2. Flash the pico with micropython: official documentation.

3. Load the appropiate file:

   • main_pico.py file for the raspbery pico.
   • main_tiny2040.py file for the tiny2040.

4. Rename to main.py for automatic execution.

Use

You may connect the pico to your phone or get a battery for power on the go :)

Here an example of a portable implementation using a Tiny2040.

Note

The script blinks the led of the pico automatically. If you are using a Raspberry pico W change the Pin defnition accordignly (link).

Results

I've added a recorded signal generated with the pico to the docs folder, sampled at 1MHz with an RTL-SDR.

The raw signal looks like this in Inspectrum.

Once we adjust the min and max power values, we can add an amplitude plot and check that it can really be decoded to the original signal.

101010101010101010101010100010101100101100110010110011001100110011001011010011010010110101001010110100110100110010101011010010110001010110010110011001011001100110011001100101101001101001011010100101011010011010011001010101101001011000101011001011001100101100110011001100110010110100110100101101010010101101001101001100101010110100101

Adjustments

The transmitted signal should have a symbol period of 400us. This is indicated with micropython's call sleep_us(400). However, thats the time the sleep call will wait, we need to account too for the time it takes to execute the rest of the code. I was getting pulses of 416us so I just compensated for them. Seems little but it's a huge difference after the 333 symbols of the signal, and it was not able to open the charging ports.

Therefore, I changed the call to sleep_us(384) and it fixed the issue.

You may need to play a bit with this parameter to make it work if you change the code ¯\_(ツ)_/¯.

Better solutions could be implemented, like using the PIO framework. Maybe I'll do it in the future.