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How Bluetooth saved my Jolly Logic Altimeter 3

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jhein

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This past sunday (10/16) was a breezy day for launching rockets here in Northern Colorado. I was flying my RW Formula 38 on an AT E23. Wanting to keep it low because of the wind. I attached my Alt3 via the usual fishing swivel hook to the nose cone. I armed the Alt3 and launched the rocket. The launch was successful and the rocket landed about 75 yards down range due to the wind.

I went to recover my rocket and download the data to my Iphone. Upon recovery I discovered to my horror that the Alt3 was missing! CRAP! Another $100 gone! http://cdn.rocketryforum.com/images/smilies/yikes.gif

At first I went back to the launch pad and try to visualize where it might have landed. The wind direction and speed was fairly constant so I figured it HAD to be somewhere between the pad and where the rocket landed. But how am I going to find such a tiny device in a dried out, overgrown dry grass field?!?

Then it dawned on me that the Alt3 most likely survived the fall to earth and if it did it was trying to do a Bluetooth pairing with my Iphone and the battery charge was near 100%. A quick google search to determine the Bluetooth broadcast range led me to believe that the Alt3 most likely had a maximum broadcast radius of 10m. What I didn't know was for how long will it continue to broadcast.

So I opened up the Alt3 app on my Iphone, and immediately saw that the app was trying to connect. I started walking in a zigzag pattern towards the landing zone. At about 50 yards it connected! OMG! I marked the first point with a stick. I then kept walking until it lost the signal. Marked the 2nd point. I continued until I had made a search square about 50 feet long. The Alt3 had to be inside the square!

After a few minutes of searching for the little black Alt3 in the brown grass and I found it intact! Woohoo! http://cdn.rocketryforum.com/images/smilies/1.gif Upon examination of the swivel hook, I noticed that the hook apparently was torn open by the ejection forces. I downloaded the data and the Alt3 lived to fly another day. I have since upgraded to a more robust hook.

thanks for reading
Jim
 

ksaves2

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Anything that can improve the ground footprint of a device, bluetooth included, has the potential of being a "local tracker". The stories of Rf beacons ripping off a shockcord and surviving a fall only to be found by the receiving station, abound in the hobby.

I had a homemade beeper with a 12V N cell fall off a rocket and I visualized where the apogee event was. I walked out there on the off chance the duct taped battery remained in contact and by golly, I heard it and picked it up in the grass unharmed.
Kurt
 

blackbrandt

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I did that with my wireless headphones as well. Dropped them one night. Ended up blasting the loudest song I possibly could until I could find them in the grass. :)
 

ksaves2

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Also, I lost a GMRS walkie talkie I was using to keep track of my autistic son at our local modroc site 3 minutes from our house. Got home and he handed me his rig and I found mine wasn't attached to my belt. Quick drive back and I was amazed I could
remember and retrace my steps I took for recoveries. Sent the call beep and sure enough, I was able to find it in the tall grass in no time. Glad travel time is 3 minutes. Kurt
 

ID Rocketeer

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Too bad the Alt1 didn't have that feature. Lost my v1 Alt1 several years ago when we flew it in my wife's rocket. The supplied metal hooks are not reliable, despite being fully engaged. :(
 

rstaff3

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Glad you got it back! I lost one to the trees and was dismayed that it was too high to detect via Bluetooth.
 

Kallahan11

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I had one in a rocket get hung up on powerlines, I was able to download the flight standing under the lines. 20+mph winds that night thankfully blew the rocket off the lines and I recovered it the next day.
 

soopirV

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I did that with my wireless headphones as well. Dropped them one night. Ended up blasting the loudest song I possibly could until I could find them in the grass. :)
I think a lot of iPhone 7 owners are going to be trying this same thing, nice solution!
 

John Beans

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Inspiring story. Glad you got it back!
Says as much about your determination as it does about the technology.
That's one of the lessons I try to instill in my kids: keep going!
 

ID Rocketeer

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While on the topic of JollyLogic products, as their web site will tell you, you'll want to keep your device charged. Unfortunately I was unaware of this and my Alt2 has been sitting in my rocket for ~4 years. Now it is on its way to JL so John and/or his staff can replace my battery. Considering the service and shipping are costing me nearly half the price of my altimeter it is something you'll likely want to avoid. Check out "Altimeter Seems Dead?" at https://www.jollylogic.com/support/
 

John Beans

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Yep, true of all rechargeable lithium batteries. If you've got a phone or tablet in a drawer somewhere, drag them out and charge them up or they'll be ruined eventually.
 

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