Never Lose a Payload Again with the R2Home GPS-Guided Recovery System

By utilizing GPS and active maneuvering, this device ensures a high-altitude payload will land exactly where specified.

Motivation for creating the R2Home

Once a payload has been lifted high into the air by either a balloon or an aircraft, it must come down eventually and be retrieved. Traditional systems rely on a single location beacon (often GPS) that tells the user where it landed. But this can lead to some problems as many areas are very difficult to access, and some, such as a river or lake, can outright ruin the payload. To address this, Yohan Hadji has come up with a system, called R2Home, that utilizes both GPS and active maneuvering to steer the descending payload exactly where it needs to go- all while remaining fully autonomous.

Slowing the descent speed

The first problem to tackle was how to decrease the speed of the payload while also allowing the entire assembly to steer precisely. Because a single, typical parachute only acts in one direction, Hadji added a second paraglider canopy that sits below the upper drogchute to adjust the direction of the payload.

When the correct altitude and speed are reached, the drogchute is released and allowed to slow the descent a slight amount, at which point the canopy is unfurled.

Adding a guidance computer

Being able to tell where the device is located in 3D space and then actively changing its direction to land in a specified area falls to the onboard guidance computer. Hadji designed and assembled his own PCB that houses a Teensy 4.1 development board along with a few connectors for attaching a GPS module, servo motors, LEDs, and power. Altitude is determined by reading atmospheric data from a BMP280's barometer which is used to tell the computer when the chute should be deployed.

The status LED lets the user know the current operating mode and if there are enough satellites detected by the GPS module.

How to release and steer a parachute

The release mechanism for the drogchute involves using a small microservo motor to unlock the top and allow the parachute to unfurl.

Once the paraglider canopy has opened below this, a pair of specialized servo motors are able to pull on each side of the canopy to cause a flex and therefore steer it in a given direction. The servos work by having a normal 360 degree servo motor which is paired with a positional feedback sensor that provides current positional data. By tracking how far the servo has spun, the amount of string released from the spool can be calculated.

Additional details

Apart from the canopy, Hadji included a fan that can quickly spin up to provide course correction as well. The whole enclosure is made from 3D printed PLA plastic which gives enough strength while also being light. You can see from his tests that the R2Home consistently lands in the correct location, even in strong winds. It will be interesting to see what else can be added to make this system more accurate.

Evan Rust
IoT, web, and embedded systems enthusiast. Contact me for product reviews or custom project requests.
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