We put a custom designed GPS logger in Keith’s rc plane. The cool part of the video starts 2/3 of the way in. I take the logged data and show it in Google Maps and Google Earth.

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Here are some direct links to Google Maps (click on “view in Google Earth” for the really cool version) :
Keith’s RC Stryker
Keith’s Green Plane

A few coworkers were talking about GPS running watches a few weeks ago. Right now they are very expensive. We started talking about ways of building something much cheaper. Here is a prototype for one made out of electronics parts that I already had

The main purpose of a GPS running watch is to show you how far you’ve run or jogged. Also, it can tell you how fast you are running both in terms of speed (mph) or how long it will take you to run a mile. Since Charlie, one of my co-workers, trained for a marathon, it was evident that he wanted to be ontop of his target time. This type of info would be crucial for his type of training purposes. I’m sure more features could and should be added.

Cost. Commercial GPS watches seem to cost anywhere from $150-500. This one is probably $20 + the cost of a GPS module. Currently the cheapest GPS modules are $40. That still puts the cost in at $60 or so.

Details. The heart of this is an AVR atmega8 running at 1Mhz. It has 8k of flash which is 99% full. The LCD display is from a Nokia 3310 and are about $6 online. The GPS module was from my UAV project that I abandoned. It outputs TTL serial which it sends to the AVR. The AVR then parses the serial string and interprets the data. Since we don’t have much room for the code in flash, lots of care has to be taken to keep the code size small (no snprintf’s here). For input, I used an IR remote. I seem to be standardizing on that these days because it only takes one pin on the microcontroller and gives me lots of buttons to use. Obviously, on a real watch it would need buttons instead.

Lastly, I should mention that LCD support was provided by CC Dharmani’s LCD library. Many things to him for helping me troubleshoot as I was bringing up the LCD.

Whats next? I’ll probably put everything into a small project enclosure so that I strap it to my arm. It will probably be so big that I won’t really want to jog with it much but I can at least see if it is really usable. If that works out well, I may try to see who else might be interested and I could make a special board for it and power it with a cell phone battery to make it only 2″ x 2″ x 0.5″ so that one could actually wear it as a watch. At that point I’d actually have to spend some $$ so I may never get to that point

Thanks for watching!

http://maps.google.com/maps?q=http://spiceland.org/makerfaire.txt

GPS + a serial terminal logger + some perl scripts + Image Magick + mencoder + cinelerra = my GPS speed overlayed ontop of a video of me driving …. yeah!