Hello...
I need scheme for digital speedo and/or odotomer
I found this project, but it seems a little bit strange... it need 8 magnets to get signal from the wheel and also i am wondering it i would be able to select it to work good on my wheel... 17"

If somebody can give suggestions, or who have time to help me with creating track view for it... would be great - i am not able to do it. (Also for led indicators great way is to use the leds on different scheme... i mean with cables... so it would be easy for creating the track view also

Thats the project: http://www.2shared.com/file/-9kCXeAm/SPODO_SUNRISE.html





I think that the difference is just for the different way of switching from the power supply(АКБ- power battery) and 'к замку зажиганя'... but i am not sure

Also here is the conversation with the owner:

Hi!
One biker (Ivan aka Sunrise) asked me for the same.
There are circuite and program for PIC in RAR that Sunrise has made and
used already. This is speedo- and odo- meter. 3 didgit speedo and 6
digit odo. Short push of button change odo/trip display mode. In trip
mode a long push reset trip.

The program can work only with one size of wheel. There is not any tool
for adjusting. But program can read partial number (not integer) of
meter per impact. Sunrise set one Hall sensor on fork (? in Russian the
detail of bike called "VILKA"=fork) and 8 magnets on moto-wheel that
makes one turn when bike moves on 1.858 meter. You can push your bike
for a known distance and count turns. After that you must calculate a
value of electric impacts from your sensor per meter. For Sunrise bike
example: 1.858 m / 8 magnets (1 impact per magnet) = 0.2325 meter per
impact. Lets X=0.2325

Haw to adjust the program for your case? (your wheel size)

You must find in source text of the program three lines

GetIPM retlw 4
GetMPI retlw d'238'
GetR3mS retlw d'246'

You must select two number GetIPM and GetMPI to satisfy
Х = GetMPI / (256*GetIPM)
with a smallest error.

for Sunrise example 0.2325 just 0.23242 = 238/(4*256)
This is necessary to adjust odo.

The therd number GetR3mS is used for setting speedo. It must be near to
GetR3mS = 1059 * X

If you will want to reduce indicated speed for 0,4% then you have to
increase GetR3mS by 1. Decrease GetR3mS to enlarge speed. GetR3mS can't
be greater than 255. And if it yelds lower than 100 or greater than 255
you must use another number of magnets.

Then you must change lines in program for your values, compile prorgam
(get HEX-file) and write HEX to PIC with a programmer-device.You can go
other way. Get HEX from RAR and open it in programmer-device control
program. You will see program code like

000000: 2821 3404 34EE 34F6 3C0A 390F 0782 3480
000008: 34F2 3448 3460 3432 3424 3404 34F0 3400
...

Correct 3404 34EE 34F6 where
04 is GetIPM
EE is GetMPI (238 in hexadecimal)
F6 is GetR3mS (246 in hex)
Change 04, EE and F6 to yours values. Do not touch other bytes! And write code to PIC.

Hi!

--- 1. Why we need so many magnets?
Speedometer counts impacts from sensor for set time period. The value of
this counter equals indicated speed. No extra calculation is need. But
this method of speed definition has a lack. If frequency of impacts is
small then period of counting must be large. 8 magnets are need to
increase impact frequency and to get counting period in range of 0,5 -
1,0 sec.
--- 2. What is АКБ and к замку зажиганя?
"АКБ" is line to on board battery. It is need only for odometer. The
line "к замку зажиганя" connects to ignition. When "ignition" line goes
off then odometer takes power from "АКБ" for short time to write
odo/strip into power free memory. If you need only speedo and didn't
need odo then just exclude odo indicators, button and "АКБ" line from
circuit.

 

nobody have better project or can help me with track view for this scheme ?