Acceleration App.

John Murch · Posted: Mon May 16, 2016 4:32 am Post subject: Acceleration App.

Has anyone any experience with an acceleration application on their smartphone or tablet? (Preferably apple). Trying to get a reasonably accurate figure based on my speedo and watch is proving difficult, I seem to lack either enough hands whilst driving or mate to sit in the passenger seat.
John

John Murch · Posted: Mon May 16, 2016 4:35 am Post subject:

I thought that it would be fun to get some figures for my WO, there seems to be very little information from contemporary road tests on prewar cars.
John

Andrew Collier · Posted: Mon May 16, 2016 5:48 am Post subject:

I've heard Torque Pro 2 for Android is pretty good but I've never used it myself, not sure if they do an Apple version.

Perhaps a dashcam? I have a dashcam that measures speed, GPS and also g-forces acting on the car. I'm away at the moment but I will give it a try when I get back as you've piqued my curiosity. I suspect there may be some lag if the speed is calculated via GPS though.

Best regards,

Andrew

John Murch · Posted: Thu May 26, 2016 4:00 pm Post subject:

There seem to be a number of apps for Android devices, but the only one I've found for apple is called Car Acceleration Measure. I'm rather a long way from my car at present, but will give it a try and report back next month. I suspect that the actual acceleration when compared with the subjective feeling will be very disappointing!
I've got a dash cam, but being a bit IT dim, haven't fathomed out how to get the playback to show time and speed! The iphone (and I assume android phones) have an accelerometer built in, so I assume the apps use that as well as gps, which may do away with the lag.
John

Andrew Collier · Posted: Mon May 30, 2016 4:22 pm Post subject:

I ran some tests with my dashcam this afternoon. It was reasonably accurate to within a second. The dashcam has an in-car microphone so I would say "sixty" when I reached sixty so that when I was playing the film back on my computer I could check the accuracy. I don't know how that would compare to a phone app.

This was in a GT Speed and I was measuring sub 5 seconds to 60. In an older car it should be more accurate.

Andrew

Stephen Blakey · Posted: Mon May 30, 2016 10:22 pm Post subject:

For cross country eventing you need to know how fast your horse is going. Some years ago we calibrated ours with a hand-held GPS. Admittedly we're talking sub 30 mph but horses change speed very quickly and the GPS reading seemed to vary pretty much in real time.

Conversely, I sometimes use a speedo app on my phone and that is reminiscent of the old chronometric speedos. It tells you what speed you were doing a couple of seconds ago. From this rather unscientific approach I conclude that the lag is more to do with the equipment than a fundamental problem with GPS.

Robert Craven · Posted: Thu Jun 02, 2016 10:13 am Post subject:

Stephen,
As you say some equipment may be better than others and it may also depend how many satellites your GPS is picking up at the particular time, but I've certainly noticed a lag in the displayed speed when I've come to a complete stop at slow speed: my Sat Nav sometimes says I'm still moving when I'm not.
Although I've got an app for my Android phone (Ulysse Speedometer) which says it has a 0-60 timer, I've not yet been able to test it. I don't think it stops counting until you reach 60 and finding somewhere suitable for such a test (especially in a 3 Litre) isn't easy.

Stephen Blakey · Posted: Thu Jun 02, 2016 10:46 am Post subject:

Turns out there are fora for acceleration apps. I don't know why that's a surprise.

Folks fit external GPS sensors to the tail of their motorbike to get a direct line of sight to the sky. They report a refresh rate of 4Hz. Not ideal, but I would have thought that shows that the system is adequate to measure the performance of a 3L, given the correct receiver.

John Murch · Posted: Thu Jun 02, 2016 11:03 am Post subject:

The 3ltr will ensure a direct line to the sky! (Well, unless you have a saloon, and those are rare).

All the apps seem to do just 0 - 60. Standing quarter mile and some 0 - 100 (well that will take a while!)

I had hoped to find something that would just output a speed / time graph.

John

Paul Spencer · Posted: Tue Jul 05, 2016 11:16 am Post subject:

John,

The two images below show the output of Torque Pro using GPS (top) and OBD (below). The GPS sample interval will, I guess, depend on the device (LG G4 phone in my case). In both cases, I had the app set to take a reading every time it changed. I have also read that the OBD sample interval is shorter for more expensive adapters. Mine is an eBay special costing about a fiver including postage from Hong Kong, so perhaps not the best (although it has been invaluable diagnosing faults in modern cars).

[/img]

John Murch · Posted: Tue Jul 05, 2016 11:47 am Post subject:

Thanks Paul.
I have yet to try out my 'Car Acceleration Measure' app on the iphone on the car, however I did give it a go on an airbus A320 at Aberdeen on Sunday. This revealed a 0 to 100kph of circa 10 secs. It also gave 20-40, 40-60 times etc. In a car best results would need a mate to give you a count down and press the button. The acceleration graph that it generated was easy to read.
I can't see any way of downloading the results, but a screen grab should work.
Life is conspiring to keep me out of my car at present, latest being a cataract op, (I may have to get some Biggles googles, ugh)
John

Dan Suskin · Joined: 22 Feb 2011 Posts: 298 Location: Georgia, USA

I use an app on my Garmin Fenix 3 watch. It is a speedometer app and is perfectly accurate and fast (as compared to the speedo in my daily car).

John Murch · Posted: Wed Jul 06, 2016 3:44 pm Post subject:

Hi Dan,

Does the watch give you acceleration figures? I've had a quick look at the spec but can't quite work out if it has this function or not.

John

Dan Suskin · Joined: 22 Feb 2011 Posts: 298 Location: Georgia, USA

John,

No - speed only.

But I do have an app on my iPhone called gMeter - it gives all you want. Screenshot attached.

Christopher Carnley · Posted: Wed Jul 06, 2016 5:35 pm Post subject:

I see in "The Times" that there is now a programme (sic) to remove the space junk, so that the communication satellites relaying the digital data for all these ephemeral gizmos, and totally superfluous apps, are not affected.

1,2 3, "God is watching us, God is watching us". Laughing

Dan Suskin · Joined: 22 Feb 2011 Posts: 298 Location: Georgia, USA

This app doesn't use GPS. It uses internal accelerometers.

John Murch · Posted: Wed Jul 06, 2016 7:46 pm Post subject:

John Murch · Posted: Thu Jul 07, 2016 5:24 am Post subject:

Thanks Dan, I see the gMeter app for iphones is available in various levels and would do the things I am interested in.

It looks a bit more sophisticated than the app I am going to try, mine is free and yours is £6.99. These things are amazing value!

The torque pro is only available for android phones.

John

John Murch · Posted: Mon Jul 11, 2016 2:43 pm Post subject:

Clutch didn't like a racing take off, so lost a couple of seconds on start off, with a bit of practice (and a better clutch) I reckon 0 - 60 mph would be about 12 secs. It feels quicker than that and is a huge improvement. I should add that the engine now has a 4 1/2 block.
This is the 'Car Acceleration App'