I have a hall-effect camshaft sensor from BMW (used in lots of models from 2010 onwards). Wiring unknown.
-3-pins.
-Contains a magnet.
-Manufactured by Continental - it says "active", meaning should have an IC inside.
specs. from continental are minimal:
-Air gap range: 0 mm to 1.9 mm (higher air gaps possible)
-Temperature range: -40°C to 160 °C
-Speed range: 0 to 4500 rpm
-Supply voltage range: 4.5V to 16V
So far it outputs no signal at all (only 50Hz noise on scope):
- consumes 0.03A @ 5V (if pins 1,3 connected to vcc_gnd)
- heats-up if pins 1,3 are reversed (gnd_vcc)
- tried all vcc/gnd/output combinations - none would react to metal being placed to it
- tried using 10k Ohm pullup/pulldown on all wiring combinations - none would react to metal being placed to it
I am certain it was working fine before removing the stock ECU.
Anyone has stumbled upon this sensor?
Anyone having a datasheet to share?
Anyone having any clue what IC might be inside? Infineon?
Anyone having any ideas what else should I try?
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HALL camshaft sensor continental bmw
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Can you find a OEM schematic which includes this sensor? That might help identify what pin is GND and what pin is +V. Also can you find a different year or different model schematic? It is common they use the same wire colors or same pin out for multiple variants of a sensor.
Many Hall sensors will typically self tune an internal gain, such that low RPM signals are amplified, and low pass filter to remove high frequency noise. Then at higher RPM, the gain is decreased and the filtering is less effective, as the energy coming from the sensors is much higher than the noise. I would expect most automotive Hall sensors are "active" sensors. Using a passive sensor simply won't work well for the noisy environment with large changes in RPM's.
It sounds like your on the right track, try to identify + and - voltages, then look for a signal on the 3rd pin. Some times the sensor is push / pull so sometimes you don't need an external resistor, and you should see if it generates a signal with out a bias resistor. However it typically needs a pull up resistor which limits the current to around 5mA. Some sensors are 5V others are 12V. So you should start with 5V and see if that works. Most 12V sensors will work down around 5V, so providing 5V is usually a safe bet. If it was getting warm, you were not properly limiting the current. It is likely you dead shorted the signal channel and broke the internals. If you don't get something with a pull up resistor, then try a pull down resistor. Again the bias resistor should limit to around 5mA.
Also remember most scope's GND strap is a GND strap, not a common strap. This is typically connected to your GND on the plug of the equipment. I mention it because this extra connection can cause odd ground loop issues, or you may think you are connecting this tinny scope probe, when you are really connecting it to a huge capacitor which is charged to what ever your local ground voltage is.
I do not have explicit information about this sensor. If I had it, I would be hacking and trashing just like you.
I'd say it is a digital hall sensor (with a latch and hysteresiss), thus an active sensor. I'd also say you could have ruined it by applying reverse polarity.
Hmmm, did you have your 1X vs 10X set on the scope? It appears to be a 500mV to 1000mV signal. That seems odd to me. Also is your 0V really 0V? I see the yellow tag on the left of the screen indicating the 0V. However you appear to be offset by about 500mV. If your 1X and 10X are mangled, that might be 5V and 10V, which would make more sense for this sensor. However the 5V offset doesn't make much sense.
yes, I have had the same doubt. Scope on 1x. Coupling=DC. The same confirmed with a multimeter.
~0.3V instead of zero. Peaks at 1.2V.
No difference if Vcc is 5 , 8 or 12V.
And current is stable at 5mA at all voltages.
I think I will buy another sensor to confirm or disprove this.
By the way, what are the STM thresholds for High/Low?
From memory, I think around 0.6 to 0.7 and below was low, and like 1.8 and above was a 1. No mans land in between. The datasheet will indicate this better than my memory.
Do you have the MAX9926 chip? We might be able to make it work with that one, which detects much lower voltages. Also we might be able to get this captured via a input op-amp circuit. Remember we have a pile of op-amps as input buffers.
