I posted this a few days ago, but something happened and the post never actually appeared on the forum. So, I will try again.
One time each year, I participate in an open road rally. The goal is to average an exact mph for the length of the two leg course. Currently we use a gps to get close to our average speed and then we use a stop watch with a series of checkpoints to narrow in on the perfect time. For example, our class is 105 mph and the perfect time for the first leg is 16:24.00. So, the team (driver/navigator) with the time closest to 16:24.00 wins. The winner is typically only off by 0.1-0.2 seconds.
This year, we added Harry's Lap Timer as a trial run to see how it would work out. As it turns out, the Lap Timer was only off by 0.1 seconds compared to the electronically clocked timed compared to about 0.4 seconds off from our manual stop watch.
The biggest error I found from both the lap timer and the stop watch is the start of the race. There is a timer/light tree that counts down to your start time. One car is started every minute and the timer is tied into the atomic/gps clock. Our error comes in timing the start of the stop watch with the exact time that the timer/light tree flashes green for us to go.
Could something be added to Harry's that would allow us to start the timer as tied into the atomic clock?
Also, we use check points near the finish and hit the split button on our stop watch to see how close we are to our target time. Harry's Timer also has splits, but the racers view only shows the "current sector" when in reality we need the total time to that check point and the total time to the next check point, etc. We do not need the split time between check points/sectors.
Could this be added to Harry's as well?
I realize this is a very specific application, but if it is possible to add these features singularly for my use, maybe we could make this an independent application that tweaks just a few things to work for us. I would be willing to talk with you offline.
Adding atomic clock and other features for road rally.
Re: Adding atomic clock and other features for road rally.
Hi,
Thought about using a standing go trigger to automatically start when you start moving. This however would introduce an error due to the time from switching light to the car actually accelerating (which is probably between 0.1 and 0.3 seconds too?). GPS time is probably good enough to make a better and more reliable solution, so another trigger type ("timed go" etc.) could solve the issue... I will add this to my list as it has several new trigger types (cam on / off, speed triggers, etc). However, as this list is long and I need to prioritize all the time, I can neither commit in general or on a time line / version. Till then, you may try the standing go trigger - maybe it is better than the manual timing...
On the separate app - that's a difficult and tight business - hope you are aware.
But please feel free to call me.
- Harry
Thought about using a standing go trigger to automatically start when you start moving. This however would introduce an error due to the time from switching light to the car actually accelerating (which is probably between 0.1 and 0.3 seconds too?). GPS time is probably good enough to make a better and more reliable solution, so another trigger type ("timed go" etc.) could solve the issue... I will add this to my list as it has several new trigger types (cam on / off, speed triggers, etc). However, as this list is long and I need to prioritize all the time, I can neither commit in general or on a time line / version. Till then, you may try the standing go trigger - maybe it is better than the manual timing...
On the separate app - that's a difficult and tight business - hope you are aware.
But please feel free to call me.- Harry
Re: Adding atomic clock and other features for road rally.
Harry:
You are correct that the "go once the car is moving" will not be anywhere close to accurate enough.
I have time to wait as the next race will not be until next August.
As far as the splits go, we would use the racers view which gives you the "Current Sector", but I know the "Splits" are available in the lap data afterwards. We need the split information at checkpoints and not sector information. If the Racers View was to give the option to switch back and forth between "Current Sector" or "Splits" at the drivers discretion (much like you already in the gps screen can change the gps format to fit what you want to see), that would total solve our split challenge and only leave the error at the starting line.
In fact, if I had to choose between the two I would pick having the "Splits" option on the racers view over the atomic clock start option.
Also, we don't need to see all splits, just the most recent split as we cross that checkpoint and then are able to adjust our speed based on what our split time was at that checkpoint.
You are correct that the "go once the car is moving" will not be anywhere close to accurate enough.
I have time to wait as the next race will not be until next August.
As far as the splits go, we would use the racers view which gives you the "Current Sector", but I know the "Splits" are available in the lap data afterwards. We need the split information at checkpoints and not sector information. If the Racers View was to give the option to switch back and forth between "Current Sector" or "Splits" at the drivers discretion (much like you already in the gps screen can change the gps format to fit what you want to see), that would total solve our split challenge and only leave the error at the starting line.
In fact, if I had to choose between the two I would pick having the "Splits" option on the racers view over the atomic clock start option.
Also, we don't need to see all splits, just the most recent split as we cross that checkpoint and then are able to adjust our speed based on what our split time was at that checkpoint.
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gplracerx
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Re: Adding atomic clock and other features for road rally.
I presume that the starting time is on the minute, so you don't really need a stopwatch. GPS Buddy would seem to be the better app. Program the start and finish points and adjust your speed to keep the ETA at the finish at the correct absolute time. In your example above it would be the starting time that you should know in advance plus 16:24.00
Re: Adding atomic clock and other features for road rally.
I am not sure how gps buddy works as I haven't tried it, but the ETA idea won't be precise enough as in the last 5 miles of the course you have both straights and curves and cannot hold a steady speed, especially at 105 mph. We need the ability to have check points during the last 5 miles in order to check our target time vs actual and then adjust our speed accordingly to get as close as possible.
Re: Adding atomic clock and other features for road rally.
That should actually be possible (one more hidden feature 99% will never discover). As an alternative it would be possible to use the lap time field (Current Lap). It shows running time and stops blinking when the lap is finished - maybe I just show aggregated sector times blinking too? Opinions?Fursty wrote:As far as the splits go, we would use the racers view which gives you the "Current Sector", but I know the "Splits" are available in the lap data afterwards. We need the split information at checkpoints and not sector information. If the Racers View was to give the option to switch back and forth between "Current Sector" or "Splits" at the drivers discretion (much like you already in the gps screen can change the gps format to fit what you want to see), that would total solve our split challenge and only leave the error at the starting line.
- Harry
Re: Adding atomic clock and other features for road rally.
Harry,
That might be a good option if the current lap blinks for a bit when it hits a split and then continues on much like the current sector field does.
It actually would be valuable on any normal track I run as well.
That might be a good option if the current lap blinks for a bit when it hits a split and then continues on much like the current sector field does.
It actually would be valuable on any normal track I run as well.
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gplracerx
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Re: Adding atomic clock and other features for road rally.
Unless there are intermediate official checkpoints, I don't see why you don't go as fast as you can so that you get near the finish line with time to spare and then slow down. I still fail to see the need for intermediate splits. All you need to know is that your average speed is greater than 105 mph. Any GPS will tell you that.
Re: Adding atomic clock and other features for road rally.
Your minimum speed limit is 20 mph under your target speed. In my class that would be 85 mph, so you cannot just slow down to 30 mph at the finish. Also, using the average speed from a GPS gets you close, but you must use some timing system to get closer. So far, I have only found one gps that gives you an average to the tenths of a mile per hour and that is still not close enough. We averaged 104.95 mph this year and were off by about .5 seconds from perfect. The winner of the class was only off by 0.12 seconds.
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gplracerx
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Re: Adding atomic clock and other features for road rally.
At 105 mph, 0.1 seconds is 15.4 feet. That's starting to push the limit for accuracy for normal GPS.
At 85 mph, you're losing about 8 seconds per mile compared to 105 mph. So if you were ahead 8 seconds, you would need to slow down to 85 about 0.5 miles from the finish line. There is an average speed penalty feature in the lap summary of HLT, but I don't know if that can be accessed in real time. You would need a recorded map of the course in HLT.
At 85 mph, you're losing about 8 seconds per mile compared to 105 mph. So if you were ahead 8 seconds, you would need to slow down to 85 about 0.5 miles from the finish line. There is an average speed penalty feature in the lap summary of HLT, but I don't know if that can be accessed in real time. You would need a recorded map of the course in HLT.