mike-s
25-12-2006, 11:42 PM
Two months ago i bought a generic pushbike speedo, but i've already come across 5 severe limitations
1) it can only show speed or time at once, not both.
2) you have to push a button to cycle between the modes to alternate
3) theres a couple of other modes such as trip distance and total odometer distance that you have to cycle through to get to the above, a good way of being distracted.
4) no backlight.
5) it only goes up to 99kmh (or mph)
In order to fix this i've had to go and buy a new one, but new ones run the light off the battery, an effective way of killing your button battery quickly. So i bought the following one off ebay.
http://images.virtualvillage.com/S00001-CYA/006.jpg
I bought it a month or so ago, it shows your speed all the time, and you can alternate between total distance, trip distance and time (it would be rare that i would need to do so, so it'd stay on the time/speed setting 99% of the time), it goes up to 199km/h and has just enough room that i can fit some silicon & micro LED's in there to wire it up to the bike power supply.
This trip meter can do any wheel size from 10cm to 4m diameter, and i'm going to use it with twin low profile rare earth magnets (from a hard drive) glued to the front wheel for accurate speed resolution (I find only one magnet goes you a delay of about 1 to 1.5 seconds on speed readout).
Anyway last week i bought a bunch of red green & amber surface mount LED's (4mm long 1.5mm wide, 3mm tall) to try out different colours, a (N4004 1Amp/150v) diode and 2x 1.2k resistors (running in parallel to get it to 510 ohm), and basically i hooked them up yesterday to the bike speedo & gave it a dummy run.
Quick tests show it's looking quite promising, it looks bright enough and illuminates the screen rather well in even the daytime. I now need to hook it up to a detatchable switchblock (if i ever decide to unplug it etc) and mount it on the dash of my bike.
to be continued....
1) it can only show speed or time at once, not both.
2) you have to push a button to cycle between the modes to alternate
3) theres a couple of other modes such as trip distance and total odometer distance that you have to cycle through to get to the above, a good way of being distracted.
4) no backlight.
5) it only goes up to 99kmh (or mph)
In order to fix this i've had to go and buy a new one, but new ones run the light off the battery, an effective way of killing your button battery quickly. So i bought the following one off ebay.
http://images.virtualvillage.com/S00001-CYA/006.jpg
I bought it a month or so ago, it shows your speed all the time, and you can alternate between total distance, trip distance and time (it would be rare that i would need to do so, so it'd stay on the time/speed setting 99% of the time), it goes up to 199km/h and has just enough room that i can fit some silicon & micro LED's in there to wire it up to the bike power supply.
This trip meter can do any wheel size from 10cm to 4m diameter, and i'm going to use it with twin low profile rare earth magnets (from a hard drive) glued to the front wheel for accurate speed resolution (I find only one magnet goes you a delay of about 1 to 1.5 seconds on speed readout).
Anyway last week i bought a bunch of red green & amber surface mount LED's (4mm long 1.5mm wide, 3mm tall) to try out different colours, a (N4004 1Amp/150v) diode and 2x 1.2k resistors (running in parallel to get it to 510 ohm), and basically i hooked them up yesterday to the bike speedo & gave it a dummy run.
Quick tests show it's looking quite promising, it looks bright enough and illuminates the screen rather well in even the daytime. I now need to hook it up to a detatchable switchblock (if i ever decide to unplug it etc) and mount it on the dash of my bike.
to be continued....