hall-effect sensor for variable hi hat control

[dm9876]

also I just had a look at the pictures of Warwicks over on the vdrum forum. His magnets are significantly smaller than my one (see pictures at the beginning of this thread where the internal diameter fits over the nut) . But obviously he got it working so I guess it does not make much of a difference?

The other point I wanted to make was that the polarisation of the magnet is important (it should be 'axial' polarisation. The other options would be 'radial' or 'diametrical' which are not suitable)

as for keeping it centered on the rod. how much of a gap is there? maybe you could sleeve the rod with some clear pvc tube, or just wrap some electrical tape to help keep the magnets centered?

[rockdude]

I've now got my Hall effect sensor ready for testing. How do I connect it to a jack? Tip, ring and sleeve goes to what ends on the hall effect sensor?

[kimouette]

I've now got my Hall effect sensor ready for testing. How do I connect it to a jack? Tip, ring and sleeve goes to what ends on the hall effect sensor?

If you bought the same sensor that I did : http://www.bitsbox.co.uk/sensors.html)
Here's the wiring :

halleffectsensor.png

VCC (Power source) = Tip
Vout (output of the circuit) = Ring
GND (ground) = Sleeve

Oh and by the way I finally managed to make it work perfectly!!!
Let's just say that the tutorial on Vdrums is a good indicator, but really not as simple to install as it may look like. I spent 2 weeks looking for pieces of diverse hardware at my local hardware shop and in the end found the very specific way to orientate the hall effect sensor and stabilize my hihat's rod so the magnets almost touch the sensor when the pedal is fully pressed (without risking to crush the sensor with the magnets). So in the end nomatter if you choose an optical controller or a hall effect sensor, you WILL HAVE to spend some time making the whole thing steady, precisely lined up and secured from rough physical movements.

Oh and one more thing... before glueing your hall effect sensor on whatever material, do some tests to find the perfect orientation. It will probably have to be less than a millimeter away from your hihat's rod, and since the sensor's 3 ends are pretty fragile, you'll want to avoid having to bend them more than once!!

[rockdude]

Thanks for the info Kimouette! I have the same Hall effect censor as you do. I'll give it a go and see if it works. I'm using Synthex 3.1 kit btw. Do I have to put the jumpers in a specific way for pedal impedance and polarity to get it to work and do I have to make any changes in the settings in MegaDrum before it shows any activity? I know I have to tweak the settings, but it would be nice if it would show activity right away and then I can tweak it to perfection.

I spent 2 weeks looking for pieces of diverse hardware at my local hardware shop and in the end found the very specific way to orientate the hall effect sensor and stabilize my hihat's rod so the magnets almost touch the sensor when the pedal is fully pressed (without risking to crush the sensor with the magnets).

Do you have a description and pictorial of how your final solution looks like? Please post it if you do

[Ken Forgettable]

hallmount.gif

You could mount it at the base like this.

[ignotus]

Hi

I've been looking around for the materials to build this hi-hat controller and came across this: http://www.sestarragona.es/PNphpBB2-viewtopic-t-51.html which might be a cheap and readily available source of neodymium magnets: old cd-roms and hard disks. I haven't got round to doing it myself (will do so today or tomorrow) but there is a chance the diameter of the ring magnet might be too small, though I think it could still come in handy, using a different setup.

It's in Spanish, but if you scroll down the thread there are pictures explaining where to look for them.

[rockdude]

I now have the same magnet and hall effect sensor as Kimouette....and I think that's the same as the others in this thread has used too. I've soldered a stereo jack to the hall effect sensor like the picture Kimouette posted for the hall effect sensor and then I connect it to the pedal input of my MegaDrum with a stereocable. I get no signal at all when using the magnet.

I have no idea if and where I should put jumpers on pedal impedance and polarity

...and I don't know how MegaDrums pedal settings is supposed to be tweaked to get any life signs.
All help is appreciated: I really want this to work. It seems like such a simple solution..if it works

[jman 31]

You can play with the pedal impedance, but it should work with the jumper either way. The pedal polarity will depend on whether you want power to the tip or the ring on your setup. I believe that Synthex has posted the jumper settings for the polarity somewhere, I will try to track them down. You won't get any signal until you put the polarity jumpers on. There will be two jumpers for polarity and one jumper for impedance.

EDIT: here it is:




Jumper A : High Input Impedance
Jumper B : Low Input Impedance
Jumper C : Tip = +5Volts ; Ring = Input
Jumper D : Ring = +5Volts ; Tip = Input

[rockdude]

Thanks for your reply.
I've tried all sorts of combinations now without any success. Since I don't really understand what I'm doing it's like a game

I've connected the hall effect sensor like this picture:

VCC (Power source) = Tip
Vout (output of the circuit) = Ring
GND (ground) = Sleeve

....And then when considering this:

Jumper A : High Input Impedance
Jumper B : Low Input Impedance
Jumper C : Tip = +5Volts ; Ring = Input
Jumper D : Ring = +5Volts ; Tip = Input

.....Should I put the jumpers like this?

[jman 31]

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.