Fuel Gauge Wiring?

Greetings

Having got the ER5 back on the road last year, legal thanks to a bicycle
speedo, my next job is to build an instrument cluster for it.

The speedo is staying as is but I am going to (re-)fit idiot warning
lights for left and right indicators, oil, water, neutral and high beam
and maybe a rev counter.

I've sourced all the bits I need from Jaycar, LEDs, resistors, mounts
and a box to fit everything in.

The sticking point is the fuel gauge - not a must-have, more of a
nice-to-have (considering its rat-bikedness).

The instruments were stripped off by a friend of mine who was staying
with me and I cannot see any obvious electrical connections - certainly
no spade connectors. There should be three connections according to the
wiring diagram for pos, neg and sender.

Here are some photographs I took of the gauge itself:

http://www.edrs.com.au/nigel/P1120011.JPG
http://www.edrs.com.au/nigel/P1120012.JPG
http://www.edrs.com.au/nigel/P1120013.JPG
http://www.edrs.com.au/nigel/P1120014.JPG

Apologies for the point and click quality.

Anyone care to hazard a guess as to connections? Or does the collective
consciousness think there is something else missing.

N/

 

No need to apologise for the quality - it's the painful size (1.5Mb+ each)
of the images which you should've taken care of

There're three solder lugs that I can see; http://yak.net.au/t1/er5fuel.jpg

I can't offer any suggestions as to which terminal is which though.

Do you have a multimeter? If so, can you check the resistance between each
of those points and post the results here? The ground terminal should be
obvious, as it should have a dead short to the chassis of the gauge (this
might even be possible to confirm visually).

Failing that... Grab a 220 ohm resistor (to limit the current) and wire it
in series with the battery positive, attach the battery negative to the
gauge chassis, then start probing around the terminals until you get a
needle deflection. Make sure to only touch each terminal for a second at a
time.

If you get a mild spark, you've found the ground terminal.

If you get nothing at all, you've found the positive supply terminal.

If you get a needle deflection, you've found the signal terminal.

As an alternative (seeing as you're replacing all the other instruments
anyway), you could get yourself an LM3914 and a string of 10 LEDs to give
you a more modern display, in keeping with the new cluster.

 

Oh my goodness - something I tell every one of my customer's employees.
Guilty as charged. Mea cupla mea culpa mea maxima culpa.

Muy gracias Bob. I /do/ wish you hadn't told me about the LM3914 though
- that's enough to take me off on another track entirely

N/

 

Hmmm...

http://www.ebay.com.au/itm/300405136838
http://www.ebay.com.au/itm/330494178594
http://www.ebay.com.au/itm/330423484228

Hardly seems worth the time 'n' effort going the DIY route these days...
Especially considering how much more visible LCD displays are in daylight.

 

Or something a little more exotic yet far less expensive...

http://www.aliexpress.com/product-f...-for-Scooter-ATV-Street-bike-wholesalers.html

Aren't you glad you asked?

 

Obviously employed as a "bar steward" in a previous existence

N/

 

I did see the Acewell 38xx series and I have to admit to just a /little/
temptation.

Only reason for the DIY is a little fun at the weekend. I have no life
<sigh>.

N/

 

I just /know/ I shouldn't go down this path but.....

Given you know just a little more than the average lurkler here, can you
take a look at this:
http://www.instructables.com/id/DIY-LED-Tachomter-RPM-gauge/
and tell me if that circuit would work with a twin cylinder machine? I'm
kind of intrigued.

N/

 

You mean, I finally get to put my electronics engineering degree to use?
Whoa! 8-P

The circuit'll work with any number of cylinders, because you're not trying
to measure a precise value - merely a calibrated scale of 0%-100%. It's just
a matter of adjusting the trimmer to suit the frequency range given out by
your bike, so even in extreme cases (16 cylinders perhaps?) you'd only need
to change a couple of components to compensate.

There is though one major problem - visibility. If you use standard 8mCD
LEDs, they'll look perfect at night but will be invisible in daylight (even
on an overcast day). If on the other hand you use 500mCD LEDs so you can see
them in daylight, you'll be blinded at night.

You could of course implement a potentiometer or switch and resistors to
manually adjust the current supplied to the display, but that'd be fiddly -
or devise a light-sensitive automatic dimmer, but that'd be more costly.

At a rough estimate of $75-$80 for parts (the semiconductors alone are
nearly $37 from Jaycar) plus several hours of dicking around, I'd have to
ask again, "is it worth it?" Sure it'd be a great adventure in
doing-it-yourself and you'll have no end of self satisfaction when you get
it working, but (1) you'll have much frustration in getting it to work (and
look) the way you want, (2) it won't look professionally done, no matter how
good you are with your hands, and (3) it is only a tachometer after all -
you'll still need to build similar assemblies for the speedometer and fuel
gauge (and potentially battery votage, current monitor, temperature monitor,
etc., etc., etc...).

I'd still go with a ready-made device (especially the $90 from China); given
that it won't look like anything anyone else has on a similar bike, it'll
have enough of the "uniqueness" you seek, and the time you spend connecting
it properly and getting it to mount without falling off at the first corner
will give you the "I did it myself" factor - and it'll have all the extra
facilities, including an odometer and trip meter.

 

Nowadays you do that kind of thing with micro-controllers.
Arduino is a popular one.

 

There is a tacho function on the trailtech voyager speedo I put on the
DR650. There is a delay in this part of the system that makes its reading
pointless.
Basically, it is too slow... Even for me at the moment!