Mobile dynometer

Hello!

im interested in building a mobile dyno with Arduino parts.

There is 2 products on the market, they are "too" expensive to buy for playing around but they seems nice though.

http://www.dynomet.dk/en_portableroaddyno.htm
http://www.insoric.com/en/products_services/insoric_realpower.php

I also want to meassure the cars weight, size of wheels and save tourqe/nm and Bhp in a diagram on android and apple devices.

Any tips what path i should go?

// J

How do those products work?

Is there independent verification that they are not just window-dressing?

In theory, if you know the mass of an object and then use an accelerometer to measure its acceleration you should be able to calculate the force.

I have not tried them, but there seem to be a number of accelerometers that work with an Arduino.

...R

It seems they use a slotted disc to sense the speed of the wheel. Since one can simply use an accelerometer it"s not clear what is the point for that

blimpyway:
it"s not clear what is the point for that

An effort to justify the high price?

...R

Hi,
The high price is because

  • the acceleration devices and the speed disc are not toys.

  • The accelerometer is not the toy devices that we use in shields,

  • They are not the devices used in xbox, Wii, PS1 2 3 4 etc.

  • They are not cheap and relatively crude devices.

  • The commercial units are guaranteed and certified units that are designed for the job.

  • The software is not cheap and the company that designs/manufactures it needs to have good liability insurance.

Tom... :slight_smile:

Tom, those are valid points in Reply #4.

However I would be more inclined to accept them if there was some evidence from the OP that the products have been independently tested - as I asked in Reply #1

Out of curiosity, to what extent are the "professional" accelerometers likely to be better?

...R

blimpyway:
It seems they use a slotted disc to sense the speed of the wheel. Since one can simply use an accelerometer it"s not clear what is the point for that

The slots in the disc are merely to allow attachment to 3/4/5/6 nut wheels of various spacings.

Its probably an encoder/gyro combination to get accurate wheel rotation information. This gives
a much better value for on-road acceleration than an accelerometer could (in the face of gravity and
vibration)

The details in making such a sensor reliable and safe (and getting approval) will dominate the cost
of the device I suspect.

You could paint stripes on the edge of the brake disc and mount an optical sensor, or even use a magnetic
sensor next to the slots of a slotted brake disc. I'd strongly suggest not driving a vehicle so modified on
the public road.

And you'll need to measure the mass of vehicle+driver accurately, and the diameter of the wheel+tyre.

Even so you'll not measure power to the wheels, only power going into kinetic energy - wind and
rolling-resistance losses are not allowed for.

Hi, Robin

Robin2:
Tom, those are valid points in Reply #4.

However I would be more inclined to accept them if there was some evidence from the OP that the products have been independently tested - as I asked in Reply #1

Out of curiosity, to what extent are the "professional" accelerators likely to be better?

...R

The units are certified for IP, and Calibration.
They work straight out of the box ready to plug and play, with lots of technical backup.
If the OP gets a generic accelerometer to work consistenty, then great, but it will take a lot of work to do.
Tom... :slight_smile:

jonase79:
Hello!

im interested in building a mobile dyno with Arduino parts.

There is 2 products on the market, they are "too" expensive to buy for playing around but they seems nice though.

Dynomet Aps
http://www.insoric.com/en/products_services/insoric_realpower.php

I also want to meassure the cars weight, size of wheels and save tourqe/nm and Bhp in a diagram on android and apple devices.

Any tips what path i should go?

// J

I'm also interested in such project. Any update on this one?