Road Tuning: Hall Sensor
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Hall Sensor
02.16
| 00:00 | Unlike a reluctor sensor, the output from a Hall sensor is a square wave that varies between ground and a high voltage. |
| 00:08 | You can think of a Hall sensor as a switch that connects to ground every time a tooth goes past the sensor. |
| 00:13 | When the Hall sensor isn't connected to ground, the input to the ECU requires a pull-up resistor so that the voltage goes to a high state. |
| 00:22 | If your ECU has to the option of a pull-up resistor on the trigger input, this will need to be turned on for a Hall sensor. |
| 00:30 | With a Hall sensor we can select if the ECU will trigger when the signal goes from low to high voltage which is known as rising edge, or when it goes from high to low voltage which is known as falling edge. |
| 00:42 | Either edge can be used and again the default settings for popular engines shouldn't need any adjustment. |
| 00:48 | While a Hall sensor is generally a cleaner signal than a reluctor sensor, it still may be susceptible to noise, and for this reason most ECUs provide filtering the same as for a reluctor sensor. |
| 01:00 | If you have two trigger inputs on your engine, then the alignment of these sensors with regard to each other is also important. |
| 01:08 | This isn't going to be an issue for most factory trigger systems, but if you've devised a custom trigger system, particularly if you're taking rpm from the crankshaft and engine position from the cam, you can get into problems if the proximity of a crank tooth and cam tooth are too close. |
| 01:26 | In the perfect world, the ECU would like to see the cam tooth occur exactly halfway between two of the crank teeth. |
| 01:33 | This makes it nice and easy for the ECU to decide where the cam trigger has occurred. |
| 01:40 | If the cam tooth is happening very close to a crank tooth, it is possible at high rpm for the cam belt to stretch slightly and allow the cam tooth to swap to the other side of a crank tooth. |
| 01:52 | This will lead to the ECU seeing either too many or not enough crank teeth on an engine cycle, and this causes a trigger error. |
| 02:02 | The only way to correctly set this is to use an oscilloscope, but this should only be necessary if you're designing a custom trigger setup or modifying an existing factory one. |
