In my quest of pulling things apart and building useless projects, I have been playing around with a RTL Spectrum analyzer / software defined radios, ADS-B signals and antennas. It all started with trying to replicate my garage door opener by reverse engineering the 433Mhz RF signals and ended up with me tracking ADS-B signals from aircraft…
As I learn more about reverse engineering I keep looking for things to pull apart and reverse around the house. Im building some home automation and as part of that Im designing the system so it knows when im close to home and opens the garage door.
The door was running a fairly common system in Australia, Merlin garage doors, I started digging around their site, resellers and other forum posts for documentation. In the end I realised they were using keeloq, an encrypted system. Not wanting to get bogged down with that, I added cracking that to the to do list and came up with a system that could receive a signal from home base and apply the voltage required directly to the Merlin system to open the door. I put together a D1 Mini with some custom firmware that will send the required 12v signal to open the door through a boost converter.
So now I have this hardware that enables me to scan RF signals with time for another project…… I came across ADS-B signals which are transmitted from aircraft and started reading up some more. Within a couple hours I ended up at the open till midnight Coles supermarket buying 2 pizza pans to make an antenna…
Another couple hours passed and I was tracking aircraft signal data within a range of around 20-30km around my home.
This coincided with my nephew asking about his present as I had just made the other one the fortnite lithophane lamp. This one being into planes, I thought Id make a little portable plane tracker for him. I just needed a way to shrink down everything….. so the plans are something along the lines of
- Raspberry pi /zero W
- SDR hardware through USB
- 2-3 servos
- laser from a cat toy
- OLED screen
- a couple buttons
- TP4056 for battery charging and USB power
- 18650 battery
- 3D printed enclosure
I thought I could expand on the project and make it a camera pan and tilt system for Aircraft buffs. Locally there are a bunch that hang out at the airport watching planes , they could set something like this up with a DSLR or even their phone as a camera. The tracker could then track the plane from up to 50km away if the right antenna is attached. Have it create an access point so you can view and control from your phone and maybe even an OLED on the box so you can choose which plane to track? Could even add a small GPS module so the unit could configure the base lat\long coordinates itself?
To make life easier the first prototype im building using an ESP based NodeMCU, 2 servos, enclosure designed in freecad and a laser from a Kmart cat toy that my cat….broke.
Still very early stages as can be seen from the photos but some codes up on github as a start that controls the servos, calculates angles and distances between the unit and set aircraft data then moves the top servo to start tracking.