Wheel speed sensor wiring for DASH2?

Viktor Larsson
Posts: 10
Joined: Sun Jun 19, 2011 5:53 pm

Wheel speed sensor wiring for DASH2?

Postby Viktor Larsson » Mon Jun 20, 2011 8:25 am

I recently purchased a DASH2 instrument from www.demontweeks.co.uk and managed to get it installed on my motorcycle yesterday. Everything is working fine and I'm really happy with it - but for one small detail.

I can't for the world of me figure out how to wire the wheel speed sensor.

I ordered two sensors, one wheel speed sensor and one oil temp.

http://www.demon-tweeks.co.uk/Motorspor ... /1296/1840

Both were supplied with instruction sheets but I thought they were a bit crude so I thought I'd ask here. I've managed to sort out the oil temp one but I'm at a loss with the speedo.

The wheel speed sensor has three wires - one black, one red (black and red) and one white (black and white). The instructions clearly state that the black is ground, white is signal / output and red is +12V.

In the case of the wheel speed sensor, the red and white wires are supposed to be joined together with a 1k Ohm resistor. That leaves two wires in the "sensor end" of the sensor cable, but three wires on the actual sensor. Am I supposed to join the red and white cables down on the sensor too or solder a separate "output" line from the white wire up to the speedo wire on the dash (brown if I recall correctly)?

Any help would be appreciated. Got a MOT on thursday so I'd like to have everything sorted out by then.

Thanks.

Rob Stevens
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Joined: Sun Oct 31, 2010 9:36 am

Postby Rob Stevens » Mon Jun 20, 2011 10:14 am

That wheel speed sensor is the one use, connect black wire to ground, white wire to the signal input of the dash, connect the red to the 5v out of the dash or 12v it will work with both, no need for a pull up resistor.

Viktor Larsson
Posts: 10
Joined: Sun Jun 19, 2011 5:53 pm

Postby Viktor Larsson » Mon Jun 20, 2011 11:23 am

Rob Stevens wrote:That wheel speed sensor is the one use, connect black wire to ground, white wire to the signal input of the dash, connect the red to the 5v out of the dash or 12v it will work with both, no need for a pull up resistor.


Thanks Rob. I'll test it as soon as I get back from work! :)

Viktor Larsson
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Joined: Sun Jun 19, 2011 5:53 pm

Postby Viktor Larsson » Mon Jun 20, 2011 6:22 pm

Well, I managed to get the MPH to show up on the dash now but it isn't registering anything when spinning the wheel.

How should I mount the sensor to get the best readings? Do I need magnets (did note that the sensor itself is magnetic) on a bolt or two on the brake disc to get a reading?

Also, I'm not entirely sure but do I need the four menu buttons to use all the functions on the dash? A lot of stuff seems to be missing in the configuration software (changing from mph to kph, miles to kilometers, etc.).

osborni
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Postby osborni » Mon Jun 20, 2011 7:10 pm

You need to mount the hall effect sender so that it will see a bolt head or six as the wheel turns. I drilled through the brake cooling backing plate to mount the sender and put a small bolt through the backside of the wheel bearing flange. Some people pick up the brake rotor bolts. Others use prop shaft or half shaft bolts.

The sender works by picking up changes in the magnetic field as a ferrous object passes in front of it. Mounting clearance is key and depending on the size of the target and the speed that the target passes the sensor at the fastest anticipated speed. The sensor may need to be less than a mm to the target.

Yes, you will need the 4 dash buttons to set up a lot of the variables and where the data comes from. Basically mandatory.
BMW 2000 M Coupe

Viktor Larsson
Posts: 10
Joined: Sun Jun 19, 2011 5:53 pm

Postby Viktor Larsson » Mon Jun 20, 2011 7:52 pm

osborni wrote:You need to mount the hall effect sender so that it will see a bolt head or six as the wheel turns. I drilled through the brake cooling backing plate to mount the sender and put a small bolt through the backside of the wheel bearing flange. Some people pick up the brake rotor bolts. Others use prop shaft or half shaft bolts.

The sender works by picking up changes in the magnetic field as a ferrous object passes in front of it. Mounting clearance is key and depending on the size of the target and the speed that the target passes the sensor at the fastest anticipated speed. The sensor may need to be less than a mm to the target.

Yes, you will need the 4 dash buttons to set up a lot of the variables and where the data comes from. Basically mandatory.


Thanks for the info.

Guess I'll have to invest in some buttons then. :(

Viktor Larsson
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Joined: Sun Jun 19, 2011 5:53 pm

Postby Viktor Larsson » Tue Jun 21, 2011 2:18 am

Quick question regarding the switches though. The manual clearly states that one wire from each switch should go to the "switch common" wire and the other to the relevant switch wire (select, menu, up or down) - but do I need to attach the +12V and ground to the Connector2 wiring harness as well or do I only need them attached on the Connector1 harness to get voltage where it's needed (for the buttons)? :?:

Don't know how this thing is wired inside so I don't want to overload it with too much voltage as the manual clearly states that damage inflicted from faulty wiring = not treated as a guarantee issue.

Viktor Larsson
Posts: 10
Joined: Sun Jun 19, 2011 5:53 pm

Postby Viktor Larsson » Tue Jun 21, 2011 4:33 pm

Well, managed to get it all working so now I'm really happy. Settled for some cheap £2 buttons. They'll do the trick for now. :)

Image

Image

As for the +12V and ground I asked about earlier: turns out they are not needed since the dash already has a +12V feed and ground from Connector1.

All I need to do now is mount the wheel speed sensor and make sure it's OK.

osborni
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Location: USA, Michigan

Postby osborni » Tue Jun 21, 2011 6:37 pm

Nice! - just need to label them now. :)

The power and ground are on the same internal bus. So you only need one of each. Some folks only use one or the other connector.
BMW 2000 M Coupe

Viktor Larsson
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Joined: Sun Jun 19, 2011 5:53 pm

Postby Viktor Larsson » Tue Jun 21, 2011 8:14 pm

Yeah, but I fit them so I would remember. Menu on the left, up / down in the middle and select on the right.

Anyway.

Back to the wheel speed sensor issue. I have it wired correctly and without the 1k resistor (as suggested above) but it doesn't seem to register a signal. I've tried holding the sensor next to the front brake disc bolts at different distances (everything from 0.5mm to 5mm) but without success.

I have everything else sorted out right now so it's kind of bothering that I can't figure out something that is as straight forward as wiring three cables.

Suggestions on how to get it working? :?

osborni
Posts: 497
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Location: USA, Michigan

Postby osborni » Tue Jun 21, 2011 9:50 pm

To register, it needs to see a ferrous object pass in front of it, not held there. Spin the wheel as you hold it there. Also ensure that the speed setting in the dash is taking input from the wheel speed, not the DL1 (GPS).
BMW 2000 M Coupe

Viktor Larsson
Posts: 10
Joined: Sun Jun 19, 2011 5:53 pm

Postby Viktor Larsson » Wed Jun 22, 2011 2:26 am

osborni wrote:To register, it needs to see a ferrous object pass in front of it, not held there. Spin the wheel as you hold it there. Also ensure that the speed setting in the dash is taking input from the wheel speed, not the DL1 (GPS).


Yeah, that's what I've been doing to try and find out the "ideal" distance for the sensor but it's not picking up anything from the six bolts that hold the brake disc.

As far as I know, the only settings you can change for the wheel speed sensor is if it's supposed to take the info from itself or from a separate data logger (for example the DL1). It is set on itself on both the speedo and odometer on the actual dash, and in the software on the computer you can't really change anything as far as I can tell. When I connected the sensor, the dash noticed the connection on it's own and the MPH/KPH showed up on the screen without me doing anything.

I really don't need that 1k Ohm resistor?

osborni
Posts: 497
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Location: USA, Michigan

Postby osborni » Wed Jun 22, 2011 12:40 pm

There might not be enough of a change in the magnetic field between the bolts and the rotor.

Take a piece of steel and rapidly wave the sensor over it and see what happens. Or wave the sensor over the rotor - but it needs to move more than a few inches away from the rotor.

The bolt that I use is a standard M8 on the back of a steel bearing flange. It's about 3/8-1/2" high and about 1/2" wide relative to the face of the bearing flange.

There is also a calibration setting in the dash to tell it how many pulses per wheel rev there are, perhaps that is off too much.

I used aftermarket sensors, not the R-T ones. But there should be something in the knowledge base about the R-T ones.
BMW 2000 M Coupe

Viktor Larsson
Posts: 10
Joined: Sun Jun 19, 2011 5:53 pm

Postby Viktor Larsson » Wed Jun 22, 2011 6:37 pm

osborni wrote:There might not be enough of a change in the magnetic field between the bolts and the rotor.

Take a piece of steel and rapidly wave the sensor over it and see what happens. Or wave the sensor over the rotor - but it needs to move more than a few inches away from the rotor.

The bolt that I use is a standard M8 on the back of a steel bearing flange. It's about 3/8-1/2" high and about 1/2" wide relative to the face of the bearing flange.

There is also a calibration setting in the dash to tell it how many pulses per wheel rev there are, perhaps that is off too much.

I used aftermarket sensors, not the R-T ones. But there should be something in the knowledge base about the R-T ones.


Yeah, I suspect something like that as well.

Gonna test the sensor more after the MOT I have scheduled tomorrow. I managed to fix the speedo issue temporarily with a bicycle speedo that's approved up to 300km/h which is more than enough.

As for the calibration on the dash, you mean for the odometer? You divide 1609 with the rolling circumference of the wheel (which in my case is 1,807m). That's the only speedo-related configuration I can find on the dash.

So the formula should look like this: 1609m / 1,807m = 890. Can't find anything about the number of pulses though, not on the dash and not in the software.

Speaking of software, there's a tab in the DASH2 config software that's marked "Other" but it's grayed out. Why is that? :?:

osborni
Posts: 497
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Location: USA, Michigan

Postby osborni » Wed Jun 22, 2011 7:06 pm

The knowledge base math assumes one pulse per rev.

Not sure about "other" - future expansion?

You can also test hall effects with a volt meter. You should see a response from the signal wire when powered and moving it over ferrous objects. Simpler than using the dash.

IIRC (it's been a few years since I did my setup) odometer and speed both come from the same calibration. Although you can get speed from the DL!, you cannot get odometer from a DL1. (something about DOT regs)
BMW 2000 M Coupe


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