Audible glide angle indicator

[crwper 7]

A couple of years ago, I started work on an audible glide angle indicator. I put together a prototype based on a Palm Pilot and Bluetooth GPS, and did a bit of testing. There was a small amount of lag, but the information was usable.

I recently started playing with microcontrollers, and thought I'd work on a hardware incarnation of the device. You can see what I've got so far in the attached photo.

The device connects to a Garmin Bluetooth GPS. and uses velocity data to calculate the glide angle. This is converted into a periodic tone whose pitch varies depending on your glide angle. By plugging a pair of in-ear earphones into the jack, you can listen to this in freefall, and get nearly instantaneous feedback on your true glide angle. Other highlights are:

- Device measures 50 x 50 x 20 mm.
- Rechargeable battery (charging circuit built-in).
- Logs data to microSD card.

As you can see, I'm just finishing off this prototype. I've been thinking about what I'd like to do next, and a couple of things come to mind:

- Recharge and transfer data through USB.
- Built-in 20-channel SIRF III GPS.

With a built-in GPS receiver, the new device would be mounted on the back of your leg, with headphone wires running up the inside of your suit.

The upshot of a built-in GPS receiver is, it costs about the same for me as the Bluetooth module, and makes for fewer components in the system. The downside is less flexibility. With the Bluetooth setup, if a higher rate GPS becomes available, you wouldn't need to replace the whole thing.

Anyway, I figured I'd write up a quick post to put the idea out there, and to see if anyone has ideas, suggestions, or is interested at all in where this is going. I realize this kind of thing is not everyone's cup of tea, but if it is yours, I'd love to hear what you think.

Michael

P.S. As with my previous work, I'd be happy to make this stuff "open source", so interested jumpers could build their own. If demand exists for a finished product as well, I'll look into that. Cost will be under $200, I think.

[unclecharlie95 3]

Nice work

BASEstore.it

[LouDiamond 1]

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A couple of years ago, I started work on an audible glide angle indicator. .

Wow, I remember that, it has been a while hasn't it? I've been involved with a few interesting things since then. I think I may be able to help or point you in the right direction with a few of the things you want to add/do,especially the GPS. I'm definitely interested.

"It's just skydiving..additional drama is not required"
Some people dream about flying, I live my dream
SKYMONKEY PUBLISHING

[DSE 3]

under 200.00? I'm in.

[crwper 7]

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Wow, I remember that, it has been a while hasn't it? I've been involved with a few interesting things since then. I think I may be able to help or point you in the right direction with a few of the things you want to add/do,especially the GPS. I'm definitely interested.

I'd love to hear your thoughts. The last time we talked, I think I was gearing everything toward the Garmin GPS 10, since it was the only GPS I could get to put out full PVT data. However, I've recently found that I can put SiRF III receivers into a "binary" mode which will give me the same information. I have not yet experimented for myself, but I think it may also be possible to increase the rate at which they return data.

Michael

[Costyn 0]

Very cool! I know I'd want one!
I also know that Klaus of Paralog fame (alias Vidiot here on dz.com) has been working on something similar, based on a PDA... but this looks pretty compact. Very nice.

Costyn van Dongen - http://www.flylikebrick.com/ - World Wide Wingsuit News

[crwper 7]

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I also know that Klaus of Paralog fame (alias Vidiot here on dz.com) has been working on something similar, based on a PDA... but this looks pretty compact. Very nice.

Thanks. A couple of years ago I was working on a PDA version as well. I started adding lots of logging functionality, plots, and so on. But, at the end of it, I felt like the focus was shifting away from what we really love to do, which is, of course, flying.

My goal with the latest device has been to create something you can just plug into, and fly. Later on, if you're interested in the data, you can download it to your computer and do all the analysis you want, but I think putting that analysis on the device itself makes complicated something which should have been very simple.

At the end of it all, I'd love it if this thing felt more like plugging into a "sixth sense", and less like obsessing about numbers after the jump.

[strop45 0]

Looks really interesting. Have you had a look at http://www.qstarz.com/Products/GPS%20Products/BT-Q1300-F.htm. 66 ch MTK GPS, -165 db runs at 5Hz and generally works better/faster than the SIRF III GPS.

Would love to built/buy one of your units or generally assist you in its development.

Wayne.

The difference between stupidity and genius is that genius has its limits." -- Albert Einstein

[Costyn 0]

You added a period to the URL which gives a 404 (always preview your posts, including links ). I've fixed it: http://www.qstarz.com/Products/GPS%20Products/BT-Q1300-F.htm

Looks like a really cool toy btw... almost too good to be true. I've found one here for $100... I think I want one!

Costyn van Dongen - http://www.flylikebrick.com/ - World Wide Wingsuit News

[crwper 7]

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Looks really interesting. Have you had a look at http://www.qstarz.com/Products/GPS%20Products/BT-Q1300-F.htm. 66 ch MTK GPS, -165 db runs at 5Hz and generally works better/faster than the SIRF III GPS.

Interesting. The only hitch, which seems to be the case with many Bluetooth GPS units, is that they only list NMEA communication. Unfortunately, NMEA never gives vertical speed, and using finite differences on altitude to get vertical speed is a notoriously bad idea.

However, it wasn't until recently that I learned SiRF III units can be put into a binary mode in which they will provide full PVT data. Perhaps this unit can do something similar.

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Would love to built/buy one of your units or generally assist you in its development.

I'll be finishing off testing of the first prototype in the next couple of weeks, and then I think I'll plunge ahead with the second (USB) prototype. This adds a bit of complexity, so I'm not completely sure what the timeline will be.

I'll have to give a bit of thought to what kind of help I can use. I am pleasantly surprised by the interest level, and I'd love to move things ahead as quickly as possible.

To recap: At the moment one of the biggest questions in my mind is whether it is better to have a built-in GPS, or to interface via Bluetooth with an external GPS. As I see it, there are benefits to both sides:

Bluetooth
- Flexibility
- Possibly a higher update rate

Built-in
- Fewer parts
- No need to purchase separate GPS

Cost of the unit itself isn't really a factor, since the cost of the Bluetooth module and GPS receiver are about the same. Any feedback here would be appreciated.

Michael

[Costyn 0]

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To recap: At the moment one of the biggest questions in my mind is whether it is better to have a built-in GPS, or to interface via Bluetooth with an external GPS. As I see it, there are benefits to both sides:

Bluetooth
- Flexibility
- Possibly a higher update rate

Built-in
- Fewer parts
- No need to purchase separate GPS

Cost of the unit itself isn't really a factor, since the cost of the Bluetooth module and GPS receiver are about the same. Any feedback here would be appreciated.

Depending on the size of the unit, I think it would be good to have separate reciever and "control unit" and have them communicate with bluetooth. In this way you can place the reciever where the communication is optimal, (say on the back of the helmet or back of arm wing or foot) and place the control unit in or on the helmet, so the wire to the earpiece doesn't have to be routed around. You can also then put the control unit where you want, it doesn't need a clear view of the sky.

Of course the downside is that you have 2 units, and one without the other is useless. You also now have 2 batteries that can be dead...

Costyn van Dongen - http://www.flylikebrick.com/ - World Wide Wingsuit News

[crwper 7]

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you'd need to place it on a helmet somewhere, with a nice view of the sky.

I've had good results mounting a Bluetooth GPS on the back of my leg, and was thinking of doing something similar with the standalone unit here. The unit is about 50 x 50 x 20 mm, so I was thinking of mounting it on a 50 mm wide elastic strap, for example, with a buckle. This could be wrapped around the thigh, and it wouldn't take much to run a headphone cable from there to your ear, under the suit. What do you think?

Michael

[VectorBoy 0]

Why no use a very detuned para glider vario. No GPS errors or palm pilot program lag but it needs to be way detuned or its going to scream your ear off. But atmospheric pressure is an absolute benchmark.

[crwper 7]

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Why no use a very detuned para glider vario. No GPS errors or palm pilot program lag but it needs to be way detuned or its going to scream your ear off. But atmospheric pressure is an absolute benchmark.

The type of vario you're describing would perhaps be useful for indicating fall rate, but this is different from indicating glide angle. Flying a suit for minimum fall rate, and flying it for maximum distance, are two completely different things.

In addition, pressure measured near the body suffers from considerable variation due to changes in body position. This is one of the main challenges in designing a reliable AAD.

In freefall, most of the usual problems with GPS (e.g. multi-path) are eliminated. If you want to measure true vertical speed, and especially if you want to measure horizontal speed, I'd say GPS is the benchmark, not atmospheric pressure.

Michael

[BrianM 1]

This could be interesting to play with under canopy, too.

"It's amazing what you can learn while you're not talking." - Skydivesg

[Basjkall 0]

Nie work
But consider changing from glide angle to horizontal speed.. Better indicator for true performance.

[mccordia 73]

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Nie work
But consider changing from glide angle to horizontal speed.. Better indicator for true performance.

Arent both as dependable of wind-speed/direction on even basis?

JC
FlyLikeBrick
I'm an Athlete?

[unclecharlie95 3]

Horizontal speed alone is only half the picture

BASEstore.it

[crwper 7]

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But consider changing from glide angle to horizontal speed.. Better indicator for true performance.

This will be as simple as changing a setting in a configuration file, I should think. Which is "better" really depends on what you're trying to do... If you just want to see how slow the suit can fall, then vertical speed is your thing. If you want to see how far you can go, then glide angle/ratio will be it.

I've found a tiny 10 Hz GPS receiver which I'm going to try using in the next prototype. It's pretty cheap, so it won't affect the price of the unit. If it performs well, I think it will dramatically improve the "responsiveness" of the device.

The plan, at this point, is to build a second prototype sometime in the next few weeks, using the 10 Hz GPS and a small chip antenna. If it goes well, I'll make a few and send them out to experienced wingsuit flyers for testing, just to make sure the design holds up in field conditions.

Michael