New track timer with telemetry for $700 ish on Kickstarter

[doozerdave]

I hate electronics. lol

What bike are you riding? If it's fuel injected it has a computer.

 

[hpvchewy]

Built in GPS module is good for 100kHz (1/0.00001s) but a 10Hz external module is better for catching lines? 10Hz is only 0.1s accuracy...

If you look on HLT's website there's an entire 20 page write up on "gps accuracy". 99.9 percent of all phones that use REAL gps (not AGPS) are only 1hz, one update per second. Some of them "fake" faster updates by just dividing the 1hz (usually by a factor of 4) and either use "read ahead" to assume the direction you're heading, or show your position 1 second behind actual, then just average out your movement. In addition to only 1 update per second, they have a very wide accuracy lock (think of a big circle, 100ft across. It assumes you're in the middle, but really you could be anywhere in the circle). The high accuracy GPS devices, in addition to providing faster updates (i.e. the 5hz UltiMate unit I use in my iPod touch 4th gen) they also provide MUCH higher positional accuracy.

Example of a high accuracy receiver showing two laps overlaid at TMP:

Do these cheap pre-paid things just turn into mini-tablets when the phone time runs out or do they get disabled completely?

They turn into tablets. You probably will lose access to the google play store and the phone may disable WiFi but you can also flash the rom on the phone and it'll unlock everything, even with no sim inserted in the phone. If you need help doing that just let me know.

 

[cors]

Built in GPS module is good for 100kHz (1/0.00001s) but a 10Hz external module is better for catching lines? 10Hz is only 0.1s accuracy...

You are right about the 0.1s accuracy, but there's more to the story. Trackmaster for Android (runs on Androd 2.2, lol) actually interpolates the data to create more data points, and is reported to do it quite well, kinda smoothing out the curve. Here is more info, and why you don't really need 10hz, 5hz is enough: http://trackmaster.trackaroo.com/forums/-/message_boards/message/43468

EDIT: chpvchewy explained what's going on better, I just saw his post.

 

[doozerdave]

If you look on HLT's website there's an entire 20 page write up on "gps accuracy". 99.9 percent of all phones that use REAL gps (not AGPS) are only 1hz, one update per second. Some of them "fake" faster updates by just dividing the 1hz (usually by a factor of 4) and either use "read ahead" to assume the direction you're heading, or show your position 1 second behind actual, then just average out your movement. In addition to only 1 update per second, they have a very wide accuracy lock (think of a big circle, 100ft across. It assumes you're in the middle, but really you could be anywhere in the circle). The high accuracy GPS devices, in addition to providing faster updates (i.e. the 5hz UltiMate unit I use in my iPod touch 4th gen) they also provide MUCH higher positional accuracy.

Yeah, this I totally agree with, I was just confused by your statement about 0.00001s accuracy.

They turn into tablets. You probably will lose access to the google play store and the phone may disable WiFi but you can also flash the rom on the phone and it'll unlock everything, even with no sim inserted in the phone. If you need help doing that just let me know.

Yeah, I guess I could root the thing. I would most likely just find a used normal phone or iPod on eBay and root it.

 

[doozerdave]

You are right about the 0.1s accuracy, but there's more to the story. Trackmaster for Android (runs on Androd 2.2, lol) actually interpolates the data to create more data points, and is reported to do it quite well, kinda smoothing out the curve. Here is more info, and why you don't really need 10hz, 5hz is enough: http://trackmaster.trackaroo.com/forums/-/message_boards/message/43468

EDIT: chpvchewy explained what's going on better, I just saw his post.

Interesting. Have any of you GPS lap timer guys compared them against IR lap timers in terms of lap time accuracy?

 

[cors]

Interesting. Have any of you GPS lap timer guys compared them against IR lap timers in terms of lap time accuracy?

I compared to lap time taken from video frame count when I first made my combo ($30 for phone, $70 for external bluetooth gps unit, 5-10 bucks approx for the Trackmaster app with the add-ons), and it was spot on (I ran the GPS at 5Hz).

 

[doozerdave]

Cool. I really like the speed and line data, but I have to resist my geek nerve. I need other upgrades first.

 

[cors]

Cool. I really like the speed and line data, but I have to resist my geek nerve. I need other upgrades first.

There's about 6 months and 20 days until you can potentially use such a thing, weather dependent, lol ...unless you plan to travel down south, of course.

 

[doozerdave]

There's about 6 months and 20 days until you can potentially use such a thing, weather dependent, lol ...unless you plan to travel down south, of course.

LOL... I know, but I have an expensive track bike shopping list, plus I'm planning to buy a new street bike.

 

[hpvchewy]

Harry from Harry's lap timer, in response to the great interest and sales after he released the Lean Angle telemetry feature, has been working hard on a filter to get rid of inaccurate lean angle spikes as well as smooth the data over all. I think he's doing an amazing job!!!

With light filter:

With medium filter:

With medium to strong filter:

The resulting video:

[video=youtube;Nr8spECUAWU]http://www.youtube.com/watch?v=Nr8spECUAWU[/video]

Sweeeet. Can't wait to try it out in the spring