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Hints on switches when MIDIfying pedals

Building organ consoles for use with Hauptwerk, adding MIDI to existing consoles, obtaining parts, ...
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pwhodges

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Hints on switches when MIDIfying pedals

PostFri Aug 14, 2009 5:51 am

I am about to MIDIfy an old pedalboard. I have the pedals and the electronics, but now need to get switches. What I can't get a handle on from descriptions of other people's work is the following:

(1) Where in the pedal movement should the switch operate, and

(2) If using reed switches, what spec is appropriate - there seem to be an almost infinite number of sizes, information to help choose the matching magnet and suitable spacing is also hard to find.

So... any hints?

Paul
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kevin_sa

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Re: Hints on switches when MIDIfying pedals

PostFri Aug 14, 2009 7:01 am

pwhodges wrote:(1) Where in the pedal movement should the switch operate


Anywhere most convenient to install the switches and get accurate switching.

(2) If using reed switches, what spec is appropriate - there seem to be an almost infinite number of sizes, information to help choose the matching magnet and suitable spacing is also hard to find.


I tried reed switches first and found them very frustrating to find space for and install. I've also found that they are extremely sensitive to the placement of the magnet. I don't think it matters at all which reed switches you get as it is only used for a basic switching circuit.

I am using micro-switches. They are easier to install and remove, more reliable and easier to solder wires to than reed switches.
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NickNelson

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Re: Hints on switches when MIDIfying pedals

PostFri Aug 14, 2009 7:54 am

pwhodges wrote:I am about to MIDIfy an old pedalboard. I have the pedals and the electronics, but now need to get switches. What I can't get a handle on from descriptions of other people's work is the following:

(1) Where in the pedal movement should the switch operate, and


I went for half way between the top and bottom of the travel. I think this is pretty conventional

pwhodges wrote:(2) If using reed switches, what spec is appropriate - there seem to be an almost infinite number of sizes, information to help choose the matching magnet and suitable spacing is also hard to find.


I've used the type 60-0515 reeds here: http://www.rapidonline.com/Electronic-Components/Sensors/Proximity-Magnetic/Reed-switches/30247/kw/reed
The magnets come from ebay, can't remember what size but I'll check this evening. They're surprisingly small and cheap anyway.

I'm inclined to agree with the previous post that reeds and magnets aren't ideal for keyboard use, but I've had no trouble using them for the pedals provided that there is space to play around with

In the picture below, the magnets are stuck to the ends of the pedals with hot melt glue, and the reed switches are on the back of the strips where you can't see them.
The component you can see is a diode, necessary if you're using the 'scanmatrix' approach. The strips are slotted so the position of the reed can be tweaked relatively
easily.

Image

I used PCBs (homemade) for this, but it would work just as well with the various bits glued to lolly sticks or coffee stirrers. In this case I
wouldn't even bother with the slots, just move them around until the position was right and tack them to the frame with a couple of
panel pins.

Nick
Last edited by NickNelson on Wed Dec 10, 2014 6:37 am, edited 1 time in total.
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kevin_sa

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Re: Hints on switches when MIDIfying pedals

PostFri Aug 14, 2009 8:04 am

oops, i didnt read the first question properly, as Nick says it is conventional for the switch to operate about halfway down
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pwhodges

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Re: Hints on switches when MIDIfying pedals

PostFri Aug 14, 2009 9:13 am

Thanks for those thoughts.

If using microswitches (which seems a good idea for simplicity) and setting the switch point halfway down (which I have now discovered is in the AGO spec), how is the rest of the pedal motion accommodated without breaking the switch...? The longest levers on the switches I found ("standard size") are only specified at 4mm over-motion.

Paul
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Re: Hints on switches when MIDIfying pedals

PostFri Aug 14, 2009 10:59 am

Hi Paul

You might find this link helpful
http://www.musanim.com/mam/organproject.html

As regards using microswitches - they are fine for stops and pistons etc., but I would be wary of using them for key contacts. Individually, they don't seem to make much noise, but using them one after another in quick succession is another story. I know somebody who used them on a pedal board and they were certainly more noisy than I would have found acceptable.
Reed switches really are not difficult in a pedal board application - but they are much more difficult to get right in a manual keyboard scenario.

Graham
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wurlitzerwilly

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Re: Hints on switches when MIDIfying pedals

PostFri Aug 14, 2009 11:28 am

To mount reed switches is fairly starightforward. You can use brass pins available from any DIY/hardware store and you can buy a simple pin punch to press them into the wood. Mount the pins a little further apart than the length of the glass of your chosen reed switch, then solder your wiring loom to the brass pins. Finally solder the reed switches across each pair of pins ad trim the excess wire ends.

It's best to use some form of adjustable mounting for the magnets, so you can set the switching point. Ceramic magnets are perfectly suitable. You can either glue them on or use the ones with a centre hole and screw them on. It would be most unwise to attempt to drill fixing holes.

Assuming you are in the UK, Radiospares have an extensive range of reed switches and suitable magnets.

http://uk.rs-online.com/web/search/sear ... %20Magnets
Last edited by wurlitzerwilly on Fri Aug 14, 2009 1:47 pm, edited 1 time in total.
Regards,

Alan.
(Paramount Organ Works)
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NickNelson

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Re: Hints on switches when MIDIfying pedals

PostFri Aug 14, 2009 12:24 pm

pwhodges wrote:If using microswitches (which seems a good idea for simplicity) and setting the switch point halfway down (which I have now discovered is in the AGO spec), how is the rest of the pedal motion accommodated without breaking the switch...? The longest levers on the switches I found ("standard size") are only specified at 4mm over-motion.


One possibility would be to use the 'roller' form of microswitch like this:

Image

I can't help thinking it would be even more fiddly to set up than reeds and magnets though.

Nick
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vidarf

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Re: Hints on switches when MIDIfying pedals

PostFri Aug 14, 2009 5:43 pm

Yep, my thoughts too.

Why not order the wire bundle from midibotique.com with reed-switches allready installed? I did that, and am VERY happy with that purchase. The switches are spaced according to a 32 pedals layout. All you need to do is to mount them onto something (the idea mentioned above with the adjustable thingies is brilliant), glue some magnets to the tip of each pedal - and you're good to go.

If your electronics works by having one common wire for all the switches, and then one single wire to each switch per pedal/input, you're good to go. You might need to modify the contact, but that's easy.
The wire thingy is made for the MCP32XR board (and I think the newer xrs version too).

The solution with adjustable holders for the switches is great, since it allows you to adjust the contact point (point of speech) evenly for all the pedals.
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Re: Hints on switches when MIDIfying pedals

PostTue Aug 18, 2009 10:30 pm

I am also adding MIDI to a pedalboard, and I like the ideas on this thread.

I have decided to use reed switches and the mcp32 board, but I have run across a few problems. For anybody that has used this board, please explain how the common wire is attached to the card. Secondly, what size and strengh magnets do you recommend for the reed switches?

Thanks in advance for your help!
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Re: Hints on switches when MIDIfying pedals

PostWed Aug 19, 2009 3:24 am

On the old versions of MidiBoutique's PCBs, the ground pins were actually labelled "Common" on the board itself. However, I have just looked up the mpc32 on the MidiBoutique website, and that no longer seems to be the case, nor is it obvious from the circuit diagrams etc. which pins are common or ground. For a definitive answer I suggest you e-mail Jordan Petkov - he usually responds very quickly.
Graham
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Re: Hints on switches when MIDIfying pedals

PostWed Aug 19, 2009 7:14 pm

If you're holding the board so that the midi jack is pointing at you, then the right-most pins in both the top and bottom row are the ground pins. I believe connecting either will work, but I used both. Feel free to send any questions you have, not that I can guarantee I know the answers, but I got the board working :).
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flydeltajets

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Re: Hints on switches when MIDIfying pedals

PostWed Aug 19, 2009 9:44 pm

My pedalboard arrived in the mail today, and luckily it was shipped with the contacts and magnets already in place!! It has a "bare" common wire on the top sides of the contacts, and I was wondering if I can re-use this, or if I should replace it with insulated wire?
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gingercat

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Re: Hints on switches when MIDIfying pedals

PostThu Aug 20, 2009 3:10 am

flydeltajets wrote:My pedalboard arrived in the mail today, and luckily it was shipped with the contacts and magnets already in place!! It has a "bare" common wire on the top sides of the contacts, and I was wondering if I can re-use this, or if I should replace it with insulated wire?


Negligable current should go through it when hooked up to an encoder board so bare wire shouldn't be an issue, so long as no other stray wires can short on it.
Regards,
Chris Blaylock
i5 4670k, 32GB RAM, Win7, 2xELO 1280x1024 Touchscreens, Focusrite Saffire, MIDISport 4x4
4 Manual Console, 32 R&C Pedalboard, 3xExpression, Solenoid coupler tabs
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wurlitzerwilly

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Re: Hints on switches when MIDIfying pedals

PostThu Aug 20, 2009 5:19 am

flydeltajets wrote:My pedalboard arrived in the mail today, and luckily it was shipped with the contacts and magnets already in place!! It has a "bare" common wire on the top sides of the contacts, and I was wondering if I can re-use this, or if I should replace it with insulated wire?

Bare common wires on low voltage busbars is a "common" occurence (sorry).
They're like that in keyboards, real and virtual organs etc.
As long as they're covered by the enclosure to keep out stray metal, they're fine. :)
Regards,

Alan.
(Paramount Organ Works)
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