vehicle acceleration measuring device

[gerry maddenParticipant @gerrymadden53711]

I need to measure and record continuously the horizontal acceleration of a small vehicle from rest up to about 70mph. Ideally this would be something small and self-contained that I can screw to the structure and connect to my laptop to download the data after each or several runs.

There are lots of all-singing all-dancing devices out there but I want something relatively simple and straightforward, non-gps, and costing less than approx £50. Does anyone have experience of such a thing and/or able to recommend something suitable please ?

Gerry

[Robert Atkinson 2Participant @robertatkinson2]

Some more information needed:
Range in G (or how long to 70MPH)?
Resolution?
Sample rate?
Size / weight limits (if its a significant proportion of total mass it will affect performance)?
Recording time (see first question)

Robert.

 

[Charles LamontParticipant @charleslamont71117]

Something like Physics Toolbox app on your smartphone?

[MikeKParticipant @mikek40713]

I was at the library today and saw an issue (within the past year) of Make magazine that used a Raspberry Pi and camera for computing object speed.  The device was stationary, outside the moving object.  (I didn’t know what “screw to the structure” referred to.)

Mike

 

[MikeKParticipant @mikek40713]

Something I just found out while searching…The toy company Mattel had made a radar gun for kids.  Should be available on eBay.  Called “Hot Wheels Radar Gun”.  Quite low cost.

Mike

 

[DC31kParticipant @dc31k]

Why the specific exclusion of GPS?

If you want cheap, it will be necessary to use GPS.

Have a look at race car/bike lap timer smartphone apps as they will do what you want. What I do not know is if they are tied to a particular circuit or have to work on the basis of a ‘lap’ (i.e. something that starts and ends in the same place.

Just some tasters:

https://www.gps-laptimer.de/products

https://www.pistonheads.com/gassing/topic.asp?h=0&f=198&t=1440523

https://vibhubithar.medium.com/collecting-vehicle-telemetry-with-pi-por-tel-device-d0d86bf08333

(https://github.com/vibhubithar/pi-por-tel)

https://www.linkedin.com/pulse/budget-race-car-data-acquisition-peter-connell

~.amazon.co.uk/Accelerometer-Logger%E3%80%91WT901SDCL-High-Precision-Magnetometer-Inclinometer/dp/B085NWVRS2

~.amazon.co.uk/Accelerometer-Inclinometer-WT901BLECL-High-Precision-Magnetometer/dp/B08SQCTN8M

[Michael GilliganParticipant @michaelgilligan61133]

Maybe this:

https://www.science2education.co.uk/product/data-loggers/LOG1286

?

MichaelG.

.

Ref. __ https://mindsetsonline.co.uk/Downloads/Mini%20dataloggers.pdf

[gerry maddenParticipant @gerrymadden53711]

Thanks chaps for your quick responses.

Good questions Robert, and I guess I should have added a little more initially. I guess my runs will last about 10 seconds with accelerations around 2m/s^2 level. Resolution I think should be preferably better that 0.1m/s^2, preferably 0.05 m/s^2.   Sample rate, I think min of 10/s would be good. In terms of weight I suppose anything less than a Kg would be fine.

Michael – your suggestions look really interesting and should easily meet the above requirements. that specific one seems to be discontinued but Im sure there is something very similar on the market.

DC31k – I thought that GPS based loggers used by ‘car people’ had a sampling time of 1 second. Having read a bit more that would seem not to be the case!

Gerry

[Michael GilliganParticipant @michaelgilligan61133]

Sorry, Gerry … I forgot to link this page:

https://mindsetsonline.co.uk/shop/mini-datalogger-acceleration/

… It would appear that they are not so much ‘discontinued’ as ‘out of stock’

[ so it may be worth asking SLS, or any other re-seller ]

MichaelG.

[SillyOldDufferModerator @sillyoldduffer]

Being Arduino minded makes that route attractive to me, especially as I didn’t know a cheap off-the-shelf solution existed until Michael found one!   Quite likely there are Smart Phone apps too, because all Smart Phones contain an accelerometer.

This Arduino project shows how its done.  As the program is written, the Arduino / accelerometer combo isn’t stand-alone – it copies accelerometer data to a another USB connected computer, which may not be convenient.  Depends on how big Gerry’s vehicle is.  Not difficult to write the data instead to an SD-card, if you know how, but Gerry may not have the time or interest to get into that.   I could have a go, but might take a while because I’m wading through treacle at the moment due to illness.

What do do with the data once collected may be a complication.   The simple case is horizontal acceleration in a straight line, which matches Gerry’s requirement, so shouldn’t be a problem.  Only one rate of change matters, keeping life simple.   Accelerating around a circular track is harder to compute because the X and Y accelerations have to be combined – because the vehicle is moving in two dimensions.    A model aircraft accelerating around a circle whilst climbing and diving is even worse.    Calculating the aircraft’s acceleration requires integration of acceleration data in all three dimensions, X,Y and Z. Hard work, at least for me.

Dave

[Michael GilliganParticipant @michaelgilligan61133]

For the iOS-enabled tinkerer …

https://apps.apple.com/gb/app/acceleration/id443427582

.

https://apps.apple.com/gb/app/physics-toolbox-sensor-suite/id1128914250

more specifically: https://apps.apple.com/gb/app/physics-toolbox-accelerometer/id1008160133

.

https://apps.apple.com/gb/app/accelerometer/id499629589

.

… and there are more

MichaelG.

[John HaineParticipant @johnhaine32865]

The Arduino Nano 33IoT has a built-in 6-axis IMU plus Bluetooth Low Energy and WiFi, and lots of application examples.

https://store.arduino.cc/products/arduino-nano-33-iot

[Robert Atkinson 2Participant @robertatkinson2]

The USB stick linked to by MichaelG is nice but does not have the required resolution / sensitivity. Only 62mG not the desired 5 or 10.
GPS receivers with 10Hz update rate are available as are complete speed loggers. Unfortunatly they don’t meet your cost requirement. This is probably due to the main market, motorsport, being high value.
Two suggestions:

Put a smart phone with app in the vehicle thas could record GPS and acceleration.
Roll your own remote GPS using a “maker” type bare 10Hz GPS module and a serial to bluetooth module and record on phone or laptop.

Robert.

[gerry maddenParticipant @gerrymadden53711]

Thank you all for the usual variety of interesting pointers and suggestions. Now that I have some some directions to follow I’ll do some digging.

Re the phones route, since I generally regards these things as a nuisance and a hinderance to getting on with more interesting things, my phone spec has lapsed badly to the point where its reluctant to do very much other than make calls.  So going down this route could kill two birds with one stone…..

But whatever way I go, I will let you know.

Gerry

[dodmoleParticipant @dodmole]

I think if I remember correctly a BBC micro:bit does the data logging you require, nice and simple and self-contained.

[dodmole]

On dodmole Said:

I think if I remember correctly a BBC micro:bit does the data logging you require, nice and simple and self-contained.

This project describes such a thing, developed in Scratch.   It uses wifi to send the data to a remote laptop. This might be a gotcha, because it would be better to log to a file on an SD card and I’m not sure the micro:bit supports them.

Dave

[Robert Atkinson 2Participant @robertatkinson2]

The microbit sensor is multi-range including +_2G which at 16 bit resolution ought to do the job quite nicely

https://tech.microbit.org/hardware/#motion-sensor

https://www.st.com/en/mems-and-sensors/lsm303agr.html

Robert.

[Cabinet EnforcerParticipant @cabinetenforcer]

I recall having an accelerometer based performance meter back in the early 2000’s , it was a g-tech performace meter that could measure 0-60 and 1/4 mile times, no data download and such on it though.

It appears that RC modelers have already developed a fully self contained GPS device for performance measurement which includes a phone app to study the data, as is the way these days.  linky:

https://www.skyrc.com/gsm020

 

edit to add they are in the region of £60

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