mak
|
| posted on 3/1/06 at 03:25 PM |
|
|
Push-bike speedo's
There is always talk on this site about using bike-speedo's in your car, but while i was at a bike shop today I enquired about it and was told
wheels taking the reading must have a dia of at least 20 inches for all of the speedos for a correct reading.
Is this really the case? And can you adjust them to be accurate? Can anyone reccommend a particular brand for compatability?
I'll be ok with my 17" s on yoko's, but what about the guys with smaller wheels?
Mark
|
|
|
|
|
emsfactory
|
| posted on 3/1/06 at 03:50 PM |
|
|
This is just bike chaps not knowing what's going on.
Bike speedos have to have the wheel circumference put in in mm's.
In the booklet it gives standard bike wheel diameters and the equivalent circumferences just for simplicity. I think the smallest they say is
17"
But you can put in any circumference you like.
I had my magnet on my propshat for a bit. worked fine untill 40 mph when it started missing pulses. Put it on the wheel and it was fine.
Mine cost 2.99 IIRC and got me through the SVA.
|
|
|
flak monkey
|
| posted on 3/1/06 at 04:16 PM |
|
|
I have been thinking about doing this as well as it seems a really cheap way to go...
However, I have had a few on my push bikes in the past. When the battery runs out the memory of the unit is lost including the odometer etc, I know it
can be reset to any value you like, but sure this defeats the point of having a permanent record of the cars mileage?
As well I would appreciate some ideas as to which ones are decent, but dont cost a fortune. Are there any out there which are backlit etc?
Sorry for the hijack... but at least its a bit relevant...
Cheers,
David
Sera
http://www.motosera.com
|
|
|
02GF74
|
| posted on 3/1/06 at 04:30 PM |
|
|
quote:
Originally posted by mak
There is always talk on this site about using bike-speedo's in your car, but while i was at a bike shop today I enquired about it and was told
wheels taking the reading must have a dia of at least 20 inches for all of the speedos for a correct reading.
Is this really the case? And can you adjust them to be accurate? Can anyone reccommend a particular brand for compatability?
I'll be ok with my 17" s on yoko's, but what about the guys with smaller wheels?
Mark
you put in tyre circumference. For a bike wheel, this would be a couple of inches to the wheel diameter but a lot more for a car tyre.
I can't see why you cannot take a bioke speedo apart and fit a LED or bulb behind the display. Most run on a button cell battery, 3 V perhaps?
Again wityh a bit of cunning, it could be powered off the car batterey plus have a small rechargeable as back up?
I've beem through quite a few bike speedo in my time and one I took apart a while back had a conductive foam type of thingy to make contact
with the LCD; once I moved it, the digits on the display never were the same so be ware.
Has anyone consisted using a PIC and an LCD display?
|
|
|
emsfactory
|
| posted on 3/1/06 at 04:36 PM |
|
|
Yep, meant outer cicrumference so hat would be tyre.
|
|
|
chrisg
|
| posted on 3/1/06 at 04:44 PM |
|
|
quote:
Originally posted by 02GF74
quote:
Originally posted by mak
There is always talk on this site about using bike-speedo's in your car, but while i was at a bike shop today I enquired about it and was told
wheels taking the reading must have a dia of at least 20 inches for all of the speedos for a correct reading.
Is this really the case? And can you adjust them to be accurate? Can anyone reccommend a particular brand for compatability?
I'll be ok with my 17" s on yoko's, but what about the guys with smaller wheels?
Mark
you put in tyre circumference. For a bike wheel, this would be a couple of inches to the wheel diameter but a lot more for a car tyre.
I can't see why you cannot take a bioke speedo apart and fit a LED or bulb behind the display. Most run on a button cell battery, 3 V perhaps?
Again wityh a bit of cunning, it could be powered off the car batterey plus have a small rechargeable as back up?
I've beem through quite a few bike speedo in my time and one I took apart a while back had a conductive foam type of thingy to make contact
with the LCD; once I moved it, the digits on the display never were the same so be ware.
Has anyone consisted using a PIC and an LCD display?
I've considered it but as I don't know what a PIC is, other than in a nose way, I don't think i'd be able to do it!
Why can't the people who know about these things make some!
I'm willing to take one off your hands, for test purposes.
Cheers
Chris
|
|
|
Avoneer
|
| posted on 3/1/06 at 05:12 PM |
|
|
I had my sensor and magnet on one of the baked bean tins on my drive shaft - worked fine for me.
Why not use a small led number plate light?
Pat...
No trees were killed in the sending of this message.
However a large number of electrons were terribly inconvenienced.
|
|
|
ReMan
|
| posted on 3/1/06 at 08:58 PM |
|
|
I was in a travel agent today, and was told that "People always think we know about the what the places are like just because we work in a
travel agents"
HTH
|
|
|
SixedUp
|
| posted on 3/1/06 at 11:50 PM |
|
|
Sigma have a good reputation for their bike computers, and I seem to remember that they actually guarantee the accuracy to "silly" speeds.
They've been used by the sevens crowd for years.
I have a Sigma Sport 800, which works well. You can get it from Argos for about £15, or over the internet for a bit less. It even comes with a formula
for calibrating it to your tyre sizes. Only problem is no backlight, and a need to do some fettling to fit it.
I fitted multiple magnets to improve the low speed resolution, and used stronger magnets to allow me to mount the sensor a little further away. I also
changed the sensor wire to a highly shielded cable, to minimise interference. I wouldn't recommend that you consider a wireless system, as it
will be swamped by interference from the cars systems.
Building your own system using PICs and an LCD would be possible, but definately more expensive than just buying a decent bicycle computer. Unless you
were going to try to make your own Digidash system, it wouldn't be worth the time, effort and cost 
Cheers
Richard
|
|
|
02GF74
|
| posted on 4/1/06 at 02:11 PM |
|
|
the probs witrh cycle computers are no backlight, possible max at 99 mph (2 digit display) and upadate.
I reckon that a PIC with a LCD display could be doable for £10-20 or so. with a bit of extra stuff, it could keep mileage and if using a 2 line LCD
show both speed and mileage. It vould aslo updare speed value faster than bike speedo.
Dunno how much the digi-dash costs though but it does sound a case of reinveting the wheel.
PIC = a single chip computer; contians processor and memory that can be programmed.
I may investigate further but there is no real incentive for me although I;d like to have an excuse to buy the PIC programming kit!
|
|
|
chrisg
|
| posted on 5/1/06 at 03:16 PM |
|
|
what gizmo would be required to step down 12 volts to power one of these speedo's?
Part numbers would be nice!
cheers
Chris
|
|
|
02GF74
|
| posted on 5/1/06 at 05:24 PM |
|
|
quote:
Originally posted by chrisg
what gizmo would be required to step down 12 volts to power one of these speedo's?
Part numbers would be nice!
depends on the battery voltage. you can get a voltge regulators in 5, 9 and 12 V, 7805 for example but thaqt gives 1 A and you can get cehaper
regulators for less current that would be more than adequate.
If it is a different voltage, then you would need to use zener diode and a transistor, a cruder version of the regulator.
... having ofcourse wirtten all that, you can get adjustable output regulators, 1.25 - 37 V,
http://www.maplin.co.uk/Module.aspx?ModuleNo=8067&&source=14&doy=5m1
or this http://www.maplin.co.uk/Module.aspx?ModuleNo=12539&&source=14&doy=5m1
|
|
|
chrisg
|
| posted on 5/1/06 at 05:47 PM |
|
|
Those are definately my sort of price!
The problem is that I dont know how to use one.
I'm electrically in competant
How about a drawing?
Or step by step instructions.
Sorry to be a pain
Cheers
Chris
|
|
|
02GF74
|
| posted on 6/1/06 at 08:54 AM |
|
|
ok, I'll take a look; may even buy one and make a small circuit up for you but need to know the battery voltage for your speedo.
I looked at 2 of my bike speedos this morning and they use CR 2032 battery that is 3.0 V.
|
|
|
chrisg
|
| posted on 6/1/06 at 03:22 PM |
|
|
Cheers mate!
I'll get one and let you know.
Thanks
Chris
|
|
|
paulf
|
| posted on 6/1/06 at 09:47 PM |
|
|
Ive got a sigma 1200 on my car , it works very well and is accurate at all speeds when checked against a gps. I extended the cable with some sheilded
cable i got from the crank sensor wiring on a sierra loom.
I havent bothered about battery back up as it is possible to re enter the milage after changing the battery .
Paul.
|
|
|
%20(WinCE).JPG)
.jpg)
