Is this possible? Using Altimeter to deploy a drone parachute

I'm very new to the Arduino and am looking to use an Arduino with an altimeter to deploy a parachute on a drone. I've done a bit of reading on altimeters in use with Arduino boards and am feeling a little overwhelmed. I was looking at using the Adafruit BMP180 altimeter - http://www.adafruit.com/products/1603

I would like to be able to define a preset maximum decent speed (say 6ft per sec) and if the decent is exceeded I want the arduino to then trigger a servo to deploy the parachute.

Is it possibly to this with the arduino boards and which board would you recommend me buying?

Any advice and or direction is greatly appreciated. I'm currently thinking that it may best to outsource this job to a more experienced coder but if I can tackle it myself I will :slight_smile:

It should be fairly easy. Even the smallest Arduino has enough pins to support a single I2C device and a servo. The program would work something like this:

Every second:
Read the pressure altitude.
If the new reading is more then 6' (2 m? 1.75 m?) below the previous altitude:
Deploy the parachute.
Record the altitude as the previous altitude.

You may want to kill the motors when you deploy the parachute so the quadcopter can't recover control and head upward into its parachute.

Instead of using rate of fall you could use an accelerometer and detect a free-fall condition (all three axes reading near zero acceleration).

Thank you very much for the reply :slight_smile:

I've thought about using an accelerometer but wasn't sure how to make it work to detect a free fall also I've ran into instances with drones where they catch their own prop wash and enter a rapid decent while not a free fall still a decent rate that is fast enough to cause damage that's why I was looking into the altimeter.

I was going to add an output to kill the motors as well.

I'd wager my next months wages against a cow pat, that, if we knew more about the application, there would be a a more reliable method of ensuring the parachute is deployed at the right time though.

I'd wager my next months wages

What sort of ballpark figure are we talking about here?

jremington:
What sort of ballpark figure are we talking about here?

Enough to buy several cowpats at current market value.

OK you are on. The neighbor's cows got out the other day and left a few for us, so I'm stocked.

HI, you could use a combination of altimeter and accelerometer.
The reason is to stop false triggering due to bumps on takeoff and turbulence on the way to release.

You arm the accelerometer to check for your negative acceleration after the drone has passed a certain altitude.

So that way you will avoid any embarrassing deployment during setup and takeoff.

Tom… :slight_smile:
I am sure there is another thread on the forum about this sort of thing. 12 months or so ago.

Thanks for the advice guys I really appreciate it :slight_smile:

KenF:
I'd wager my next months wages against a cow pat, that, if we knew more about the application, there would be a a more reliable method of ensuring the parachute is deployed at the right time though.

The idea atm is to mount the system to a phantom 2 quad and use a spring deployed shoot if that helps at all... The idea of using the Arduino is that it will be isolated from the rest of the quads systems in the event of a major failure.

How to Make One

Greensprings:
How to Make One

The link has failed again. I'm guessing you mean THIS one. :slight_smile:

Pretty cool stuff.

That's cool but not what I'm trying to do lol.