Philip Martin wrote:
>
> Hi Tony,
>
> All I am interested in is obtaining the average speed over the distance.
> Thus, from a standing start the time taken to cover the distance will (I
> think) be representative of the speed including the acceleration time.

If you do a standing start and assume constant acceleration upto the end
point, the average speed will be half the final speed.

Example

 Secs        MPH
 0           0
 1           10
 2           20
 3           30
 4           40
 5           50
 6           60
 7           70
 8           80
 9           90
10          100

Add then all up and divide by 11 = 50 MPH

That's assuming constant acceleration. Real life will be totally
different.

Example (sort of logarithmic)

 Secs       MPH
 0          0
 1          10
 2          25
 3          45
 4          65
 5          75
 6          83
 7          90
 8          95
 9          98
10          100

Add then all up and divide by 11 = 62 MPH

As you can see the total time and final speed are the same, but the
average is diferent.

I would imagine you would need to take speed readings at set points
along the track to find a true average.


> Therefore so far the PIC division is concerned, it provides the number of
> whole subtractions it can make, plus the remainder left over, that is
> undividable, rather than the true division.
>
> To gain the decimal places you can then multiply the remainder by 3E8 (1000)
> and divide it by the original divider to get the first three decimal places.
>
> Does this make sense, or have I got completely the wrong end of the stick?

Sounds reasonable.

--
Best regards

Tony

mICro's
http://www.picnpoke.com
mailto:sales@picnpoke.com

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