Landracing Forum
Tech Information => Technical Discussion => Topic started by: jdincau on June 27, 2012, 11:13:22 PM
-
Anyone have pictures or descriptions of wheel speed sensor instalations? I mean non stock custom install not factory ABS or traction controll.
-
There are many ways to do it, but here is a simple one. Tony
Picture from the net
(http://i273.photobucket.com/albums/jj236/maguromic/WheelSensor.jpg)
-
This is a bike set up obviously, the magnet is glued to the disc and the pick-up glued (sikaflex) and cable-tied to the fork leg. Minimum clearance between the the magnet and pick-up. The unit is a trail tech Vapor. It allows me to monitor mileage for oil change and service intervals, more than telling what speed the bike is doing, though it does do that also.
http://trailtech.net/vapor.html
(http://i1177.photobucket.com/albums/x347/pandoras_bits/0ec42862.jpg)
-
Tony, that is perfect, what does the sensor react to in the pictured install you posted, the vanes in the rotor?
-
This is from that particular sensor manufactures website.
"This sensor can pickup up a signal from any metal bolt. The most common installation for the Speed sensor is to point the sensor at the bolt(s) that hold the Brake Rotor or Wheel Hub on. If you have a stock car, this is the most popluar installation on wide five, or 5 on 5 wheels. An alternative method on some racecars is to attach a bolt to the rotating hub and have it pass by the sensor".
There website is http://www.advantagemotorsports.com/Sensors.htm about half way down on the page.
On the cars I am helping build we are picking up from a rotor bolt, though our mounting is a little more complex due to our shrouds for the inside of the wheel. Tony
-
Does anyone have experience with a good 3 wire 5 volt feed analog sensor they would recommend?
My old 02 data logger doesn't do frequency inputs.
Thanks
jon
-
Any proximity sensor will work.
If you are data logging a single pulse per rotation will do.
In any case you have to do the math, and it won't tell you a thing about tire growth.
If you want to use it for active feedback, then you are going to need a dozen pulses per rotation or more to get feedback you can use.
-
My friend makes these pinion speed sensors .
http://www.google.com/url?sa=t&rct=j&q=%22motor+sports+innovations%22&source=web&cd=5&ved=0CFoQjBAwBA&url=http%3A%2F%2Fwww.motorsportsinnovations.com%2FHolley%2Fholley-efi-sensors.html&ei=YZLsT7WSIIaC6QGT2ajXBQ&usg=AFQjCNELWMv5x2wkKV2snD5aeV00sZGFHg&cad=rja
-
John Burk,
That is pretty trick stuff!!
BTW: Are we going to see you AND your car this year at Speed Week??
Rex
-
Almost but not quite . Health problems slowed me down recently . Next year for sure .
-
Here's the one I just added to the Bockscar's left front wheel to hook up to the Motec I am installing. It is a 3 wire hall effect, the slightly modified 1/4 inch bolt next to the sensor is the signal generator... basically a single gear tooth to count wheel rotations. If I calibrated it right the speed will show up in the internally recorded Motec data.
-
Another way of placing speed sensors is to put it on the drive shaft.
It somewhat simulates a multiple mag/bolt on the wheel and does infact takeinto account wheelspin from either wheel (rear).
Used to help monitor LSD units on RR cars.
John
-
UPDATE
:-o
What is the difference between a 2 wire and a 3 wire pickup?
-
Hall effect or magnetic. Depends on what you are using to record with.
-
Here is the spec for the 3 wire I am using it is a hall effect with a power, ground and signal output. The 2 wire type is just an on/off switch activated by a magnet.
-
Thanks Jim
-
Here is the spec for the 3 wire I am using it is a hall effect with a power, ground and signal output. The 2 wire type is just an on/off switch activated by a magnet.
Slight correction, the 2 wire type has a winding around a magnet in the sensor, and the tone ring is a toothed wheel. The teeth passing through the magnetic field generate a voltage that is read as speed.
-
so what about the ones that pass over a magnet? That is just generating a frequency that is being logged and converted to rpm or such am I understanding this correctly?
-
often a reed switch if a magnet is involved
-
often a reed switch if a magnet is involved
Oh yeah, sorry, I forgot about that style since nothing I deal with uses them. :lol: Tunnel vision on my part I guess.
-
Two wire sensors are generally Variable Reluctance (VR) and three wire are Hall Effect or "logic sensor" (logic being in a state of either on or off). There is always a magnet involved in some way. Most VR sensors have the magnet inside of them and when a ferrous target passes them, they generate their own AC voltage that looks like a sine wave. MSD changed it up and made the magnet the moving target and put the ferrous core inside the sensor. Same exact concept, just a different way of doing it.
Hall Sensors are "powered" by either 5v or 12v depending on the sensor. Hall sensors work on a principle similar to VR sensors and also use a magnetic field. Many/most Hall sensor are "open collector" which is just a fancy way to say that they output a ground signal when triggered on. What the receiving electronics want to see is a square wave (usually at 5v or 12v amplitude). Well since a ground signal alone has no amplitude, there is a pull up resistor in the signal circuit that "pulls up" the signal's voltage to something like 5v or 12v in order to get the signal to transition from high to low as the sensor turns on and off. Some sensors have a pull up resistor already in them and output a square wave by default but this comes down to the specific sensor - check the sensor's spec sheet.
Won't be long and we'll be talking about noise cancellation techniques...
-
Thanks Nathan, looking forward to when you share your thoughts on "The Noise"