CrashPad

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  If you didn't snap it, did it really happen?

Inspiration

One of the biggest challenges facing first time drone flyers and owners is the significant risk they face of crashing their investment at one point or another. While stronger materials and crash mitigation software are reasonable advancements being made to extend the service life of drones, one of the most effective methods to prevent damage to a drone is to cushion the landing and minimize impact damage. With this idea in mind, we set out to develop an independently powered system that would intelligently deploy a 'crash pad' in the event that the drone started to enter a free fall. If implemented correctly, this system allows new quadcopter and drone enthusiasts to safely attempt light or hovering maneuvers while resting assured that their quad will remain safe in the event of a total systems failure.

We came to the hackathon with a different idea in mind, as well as what we thought were the correct hardware tools. However, after realizing that we lacked both the proper setup and equipment to go through with our original project, we decided to use what we had with us, as well as the resources afforded to us by the Maker Space. This project is an extension of the best result we could hope to achieve with the tools at hand, and we think we did a pretty good job using all resources as best we could.

What it does

When the device senses that the flying body is in a state of freefall (measured via an independent accelerometer), it activates servos that release a 3D printed 'landing pad' that is meant to simulate a shock absorbing honeycomb structure. This system is meant to be completely independent of the main quadcopter power system so that it can remain active in the event of a battery disconnect mid flight, which is a common mishap amongst quadcopters that are being flown by inexperienced pilots. There were plans to implement a rangefinding sonar in order to measure the height of the system in addition to the free fall acceleration, but the system consumed too much power with the addition of the sonar unit. This option was not further explored due to time constraints.

How we built it

We scrounged around the Home Depot trash cans to find scraps of wood to represent our flying body to be used as the base of the project. The electronic setup is entirely independent, and so was coded and configured separately. Once this was done, the electronics were mounted on top and different parts for the landing pad were laser cut and 3D printed. Once those were complete, the finished product was bodged together with duct tape, rubber bands, and super glue. The free fall sensing system is based around the implementation of a Sparkfun accelerometer wired up for I2C communication with a host Arduino unit. Once the system detects the accelerometer in free fall or rapid acceleration (corresponding to most free fall conditions), it is coded to move two servos into specific positions to deploy the landing pad.

Challenges we ran into

The specific design of the retraction mechanism took the most time. Even though this is just intended as a proof of concept, the design to release the pad took an inordinate amount of time to put together. The electronic setup also took a bit of time to code and put together, but once it was completed, it stopped giving us issues for the most part. The lack of jumper cables for us to use was a major annoyance. We ended up just using stripped breadboard wire, but it doesn't hold together very well.

Accomplishments that we're proud of

Utilizing the accelerometer to detect freefall via certain threshold acceleration values is pretty neat, as is the conditional retraction of the pad. We're also proud of the fact that such a ragged system demonstrates a proof of concept very well. This also seems to us to be a very novel way to implement a crash mitigation system, and with enough refinement, it can meet our vision of being entirelt stowed away and out of sight during flight and only visible when deployed. 3D printing a hinge was also pretty cool.

What we learned

How to make compromises and engineering decisions to deliver a finished product on time. Working with 3d printers and lasercut wood

What's next for Crashpad

Streamlining the design so it is truly independent of whatever vehicle it is mounted on and can function on any given system. The end goal would be to see some form of crashpad available to mount unobtrusively on most major quadcopter configurations.

Built With

• 3d-printing
• arduino
• lasercut-wood
• servos