Cam signal idea for full sequential
#23
Thinking along similar lines could I use the standard EM mag sensor and a thin steel steel 'sheet' glued on there? How small and thin could the sheet be? Would the studs passing nearby result in interference? Any electrical engineer types out there or anyone with the right equipment to test this kind of idea?
#24
You might have to do a little signal tweaking, but I don't think it would be a big deal. I'm not sure how hard it would be to fake a VR signal, and I guess you don't want to do soldering in your case?
If you don't mine, then, I'd pull the gear, drill a hole in it, glue the magnet into the hole (should offset the weight a bit, you could even put a bolt on the opposit side for balance but I don't think you'll need to bother. It could be inboard of the adjuster bolts for minimal unbalancing.)
I guess the first thing to figure out is if it's a VR sensor for sure, or a hall. If it's a hall it's putting out a processed signal anyway. My guess would be VR though.
Anyone think we could take a hall signal, put an offset on it, and use the same "zero crossing" input from his VR sensor?
If you don't mine, then, I'd pull the gear, drill a hole in it, glue the magnet into the hole (should offset the weight a bit, you could even put a bolt on the opposit side for balance but I don't think you'll need to bother. It could be inboard of the adjuster bolts for minimal unbalancing.)
I guess the first thing to figure out is if it's a VR sensor for sure, or a hall. If it's a hall it's putting out a processed signal anyway. My guess would be VR though.
Anyone think we could take a hall signal, put an offset on it, and use the same "zero crossing" input from his VR sensor?
#25
You might have to do a little signal tweaking, but I don't think it would be a big deal. I'm not sure how hard it would be to fake a VR signal, and I guess you don't want to do soldering in your case?
If you don't mine, then, I'd pull the gear, drill a hole in it, glue the magnet into the hole (should offset the weight a bit, you could even put a bolt on the opposit side for balance but I don't think you'll need to bother. It could be inboard of the adjuster bolts for minimal unbalancing.)
I guess the first thing to figure out is if it's a VR sensor for sure, or a hall. If it's a hall it's putting out a processed signal anyway. My guess would be VR though.
Anyone think we could take a hall signal, put an offset on it, and use the same "zero crossing" input from his VR sensor?
If you don't mine, then, I'd pull the gear, drill a hole in it, glue the magnet into the hole (should offset the weight a bit, you could even put a bolt on the opposit side for balance but I don't think you'll need to bother. It could be inboard of the adjuster bolts for minimal unbalancing.)
I guess the first thing to figure out is if it's a VR sensor for sure, or a hall. If it's a hall it's putting out a processed signal anyway. My guess would be VR though.
Anyone think we could take a hall signal, put an offset on it, and use the same "zero crossing" input from his VR sensor?
I like the magnet in the cam gear idea. I have to take all this apart some time soon as I want to fit an ATi damper. Where to source a suitable small magnet from though? Also I am not sure what parts (sensors) I would need to make this idea work.
#26
I'm pretty sure any old strong magnet would work. Some rare earth. The sensor will likely have a spec. Hmmm. I wonder if SparkFun would have something like this?
Digi-Key - 620-1185-1-ND (Allegro Microsystems Inc - A6850KLTR-T)
SparkFun Electronics - Dual Axis Magnetic Sensor Eval Board - Honeywell HMC1052L
But probably something from McMaster would make more sense. Honestly, I'd get one off the distributor of an 80's dodge. They used Hall sensors for exactly this application, these speeds, these temperatures.
SparkFun Electronics - Photo Interrupter CNZ1120 A tall bolt would work with this well.
Digi-Key - 620-1045-ND (Allegro Microsystems Inc - A3230LUA-T)
This is basically what you want. There's tons of signals out, but you want a power, ground, signal, and just glue/bolt it inside the cover, call it good.
Edit: Interesting, that last one is designed for ring magnets - i.e. you could use a round magnet on the face of the gear, instead of a single embeded spot. Personally, I like the single dot idea, but it's a way to go. You'd get a rising edge on one cycle, and falling on another.
Digi-Key - 620-1185-1-ND (Allegro Microsystems Inc - A6850KLTR-T)
SparkFun Electronics - Dual Axis Magnetic Sensor Eval Board - Honeywell HMC1052L
But probably something from McMaster would make more sense. Honestly, I'd get one off the distributor of an 80's dodge. They used Hall sensors for exactly this application, these speeds, these temperatures.
SparkFun Electronics - Photo Interrupter CNZ1120 A tall bolt would work with this well.
Digi-Key - 620-1045-ND (Allegro Microsystems Inc - A3230LUA-T)
This is basically what you want. There's tons of signals out, but you want a power, ground, signal, and just glue/bolt it inside the cover, call it good.
Edit: Interesting, that last one is designed for ring magnets - i.e. you could use a round magnet on the face of the gear, instead of a single embeded spot. Personally, I like the single dot idea, but it's a way to go. You'd get a rising edge on one cycle, and falling on another.
#29
I'm pretty sure any old strong magnet would work. Some rare earth. The sensor will likely have a spec. Hmmm. I wonder if SparkFun would have something like this?
Digi-Key - 620-1185-1-ND (Allegro Microsystems Inc - A6850KLTR-T)
SparkFun Electronics - Dual Axis Magnetic Sensor Eval Board - Honeywell HMC1052L
But probably something from McMaster would make more sense. Honestly, I'd get one off the distributor of an 80's dodge. They used Hall sensors for exactly this application, these speeds, these temperatures.
SparkFun Electronics - Photo Interrupter CNZ1120 A tall bolt would work with this well.
Digi-Key - 620-1045-ND (Allegro Microsystems Inc - A3230LUA-T)
This is basically what you want. There's tons of signals out, but you want a power, ground, signal, and just glue/bolt it inside the cover, call it good.
Edit: Interesting, that last one is designed for ring magnets - i.e. you could use a round magnet on the face of the gear, instead of a single embeded spot. Personally, I like the single dot idea, but it's a way to go. You'd get a rising edge on one cycle, and falling on another.
Digi-Key - 620-1185-1-ND (Allegro Microsystems Inc - A6850KLTR-T)
SparkFun Electronics - Dual Axis Magnetic Sensor Eval Board - Honeywell HMC1052L
But probably something from McMaster would make more sense. Honestly, I'd get one off the distributor of an 80's dodge. They used Hall sensors for exactly this application, these speeds, these temperatures.
SparkFun Electronics - Photo Interrupter CNZ1120 A tall bolt would work with this well.
Digi-Key - 620-1045-ND (Allegro Microsystems Inc - A3230LUA-T)
This is basically what you want. There's tons of signals out, but you want a power, ground, signal, and just glue/bolt it inside the cover, call it good.
Edit: Interesting, that last one is designed for ring magnets - i.e. you could use a round magnet on the face of the gear, instead of a single embeded spot. Personally, I like the single dot idea, but it's a way to go. You'd get a rising edge on one cycle, and falling on another.
#31
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You see the two raised bumps at the top of the outer section and the one raised bump at the bottom (by the white dot)? Those are part of the OEM casting, and they're what the cam sensor reads in the '99-'00.
#35
Also, the miata sensor is a VR sensor, not a hall sensor. It "emulates" hall sensor output (i.e. the conversion to digital is done in the sensor, hence the 5V feed), but it's actually a VR.
But hall sensors are not hard to find. I listed one which should work just fine, and number of those will work.
-Abe.
#38
That's not a Toda in the picture. Its some home brewed one off that I found on ebay. Very well machined, made from good materials and cad plated. Trusted it enough to put on the car. What caught my eye on the original NA pulley was the adjuster disc being inside the circle of the timing nubs so I could copy the modified outer with an NB gear to take advantage of that. Makes cam timing changes on the dyno easier if you're using the OEM hall sensor.
__________________
#39
What year CAS are we talking here?
The CAS from 1990-1997 outputs two separate signals to drive the injectors and ignition coils.
One signal is a square wave 0-5v. The other if I remember correctly is an analog ac type signal.
There is no VR sensor in a Miata CAS from 90-97
The VR sensor is on the OBDII cars from 1996 on...but that is at the crankshaft, not the CAS.
I am going to look through my waveforms and see if I have a CAS signal. If I don't I will get some and post them here.
The CAS from 1990-1997 outputs two separate signals to drive the injectors and ignition coils.
One signal is a square wave 0-5v. The other if I remember correctly is an analog ac type signal.
There is no VR sensor in a Miata CAS from 90-97
The VR sensor is on the OBDII cars from 1996 on...but that is at the crankshaft, not the CAS.
I am going to look through my waveforms and see if I have a CAS signal. If I don't I will get some and post them here.
Last edited by mrtonyg; 06-26-2009 at 09:21 AM.