hall-effect sensor for variable hi hat control

[rockdude]

Yes that looks correct to me. Did you try the pedal impedance on both settings? I have no idea how much resistance a hall effect sensor has. I would assume that you need to set the impedence the same as an optical hat which is low impedance. So the pedal impedance should probably be on the B setting.

Get out your trusty multi meter and check a few things. Set your meter to a DC voltage higher than 5 volts. Connect your red lead to the tip and the black lead to the sleeve. You should be reading +5 volts or there abouts. Next check the voltage on the ring and sleeve. See if that voltage changes as you move the magnet closer to the sensor.

Ok I tried my multimeter for the first time ever
I put the jumpers as you suggested.
I'm not sure if I did this correct, but with MegaDrum powered, I placed the red lead from my multimeter on the tip of the jack connected to the hall effect sensor and the black lead to the sleeve of the jack. Result: 4.25
When I place the red lead on the ring of the jack and the black on the sleeve I get 0.68 and nothing happens when I move the magnet closer to the hall effect sensor.

[Ken Forgettable]

Try: http://www.allegromicro.com/en/Products/Design/an/an27702.pdf
... or another magnet.

[rockdude]

Try: http://www.allegromicro.com/en/Products/Design/an/an27702.pdf
... or another magnet.

Not the solution I was hoping for. The magnet and sensor are proven to work by others so I hope there's something I'm missing.

[jman 31]

Sound's like you are getting the proper readings, except that the voltage from the sleeve to the ring should vary when you bring the magnet near it. Try a different magnet if you have one handy. Maybe the one on a speaker or something to see if that has any effect. If the hall-effect sensor is a static sensitive part, it may be fried if you didn't remove the static from your body when you handled it. I am not sure if they are or not, but it's a possibility.

One other thing. Make absolutely sure that you are looking at the sensor the way it shows on the datasheet and not backwards. If all else fails, try switching pins 1 and 3 and see if that makes any difference.

[rockdude]

Sound's like you are getting the proper readings, except that the voltage from the sleeve to the ring should vary when you bring the magnet near it. Try a different magnet if you have one handy. Maybe the one on a speaker or something to see if that has any effect. If the hall-effect sensor is a static sensitive part, it may be fried if you didn't remove the static from your body when you handled it. I am not sure if they are or not, but it's a possibility.

One other thing. Make absolutely sure that you are looking at the sensor the way it shows on the datasheet and not backwards. If all else fails, try switching pins 1 and 3 and see if that makes any difference.

This is the magnet I'm using:
http://www.supermagnete.de/eng/R-12-09-1.5-N

This is the hall effect sensor I'm using:
http://www.bitsbox.co.uk/data/Allegro1302.pdf

I'll don't have any other magnets that I think will work. I tried with a kitchen magnet without success. I'll try your other suggestions and report my findings.

[rockdude]

Tried my other hall effect sensor...I ordered two of the same. No luck. Tried switching pins 1 and 3 but still no luck. Could it really be the magnet? Am I missing something vital in the MegaDrum settings? Something like "Oh you idiot, you should set that to YES and it will work like a charm"

[jman 31]

Am I missing something vital in the MegaDrum settings? Something like "Oh you idiot, why should set that to YES and it will work like a charm"

Very possibly. I had to really experiment with my settings with the optical hat before I got it to work. You might try asking one of the others that have used this sensor to give you their settings that they had luck with. Even if they are not perfect, they may give you a starting point.

[Ken Forgettable]

This is the magnet I'm using:
http://www.supermagnete.de/eng/R-12-09-1.5-N

This is the hall effect sensor I'm using:
http://www.bitsbox.co.uk/data/Allegro1302.pdf

Both parts look ok to me - N45 is good and strong. http://e-magnetsuk.com/magnets/neodymium_magnets/ring_magnets.aspx
Check the 1302 is wired according to page 3 of your link - there should be 5v in and +-2.5v out when the south pole is brought close to the marked side.

My previous appliction link shows how to better bias the output but you should be able to pick up the output with a multimeter ok, even without any bypass cap'.

There's some talk of a bypass cap between vcc and earth but I don't think it means much.
http://www.allegromicro.com/en/Products/Design/hall-effect-sensor-ic-applications-guide/ is a very good read if you have the interest.

Anyone know where to get the A1395 part?

[anttipi]

I'm trying to figure out how to implement a hall sensor to my hi-hat stand as the pipe/tube inside which the rod is inserted is metal all the way up. I fear using a magnet on the hi-hat clutch would probably "glue" the hat in the down position.

I may have to try to assemble it down on the pedal somehow with the sensor on the floor level and magnet on the pedal. The problem is that the movement of the pedal is not symmetrical: in addition to up & down movement there is also some degree of to & fro. Meaning the magentic field would not be completely symmetrical/even across the pedal movement distance. Maybe this could be fixed using Megadrum's various curves... or perharps not?

Any suggestions?

[rockdude]

Ok I've tried all sorts of combinations to get my hall effect sensor to respond in any way and it's seem like both of them is totally dead strangely enough. I just tried connecting a linear 100k potentiometer and I got a signal without much tweaking...does that mean that I can rule out a faulty pedal input?

I must have either fried both my sensors...if that's possible..or I'm missing something vital...or got the wrong stuff when ordering....or a bad magnet...
The most frustrating thing is that this is supposed to be so easy....even to me.

I'm doomed to use my potentiometer hihat controller build that I'm not very pleased with
(I managed to wreck my optical hihat build when trying to making it work..maybe I should buy a finished and tested optical hihat controller from Jman to see if my MegaDrum likes it )