03-05-2015, 01:56 PM
Following a couple of requests about converting a USB pedalset to Bluetooth, I thought I'd show how I did it.
Being a cheapskate, I had originally opted to use a USB pedal, as they were a lot cheaper (and, I suspected, more reliable).
However, continual plugging and unplugging of my pedals seems to wear out the connector and I began to realise there were
some advantages in having a wireless solution. Commercial pedals are not cheap, so I thought it might be a good idea to start
off with what I already had and see how it went.
Up until now, I have been using a three pedal unit like this one - http://imageshack.com/i/eyWhSoUFj - these are on the net
at around the €20 mark. Actually, they work well, but my problem was the connectors on my tablet, they are really poor
mechanically and have become very intermittent over the past 18 months.
Initially, I started off with the idea of modifying a Bluetooth mouse, but I had a lot of problems with these things timing
out and that was something for which I never found a solution. Someone else on the forum had already mentioned the Adafruit
EZ-Key - https://www.adafruit.com/product/1535 - and this seemed like a good starting point, so I bought one.
Having received the EZ-Key module, I set about modifying the pedals.
The EZ-Key runs on anything from a 3v supply upwards. I use 3.7 volt lithium batteries to power my Casio midi guitar, so I
already had a number of these to hand. One AA size battery is sufficient to power the EZ-Key. I needed something to house
both the electronics and the power supply, so I purchased a switched 3AA battery holder - http://imageshack.com/i/paCkuLwwj -
modified as follows.
As supplied, the battery holder looks like this - http://imageshack.com/i/exWdgsuGj - and my first move was to alter it to
accept a single AA cell. This was quite easy, all that was needed was to remove the connecting links between the separate
compartments, cutting one in half to provide the positive connector for the single battery compartment that was left -
http://imageshack.com/i/ipluJWV9j . The positive connector that remained was a little 'loose', but I decided that the spring
of the negative connector was enough to keep the whole thing in place. You could glue it in place, if you really thought it
was necessary.
A quick check with a voltmeter was made - http://imageshack.com/i/idJP2eH2j - just to make sure the power (and switch) worked
as expected.
Next, I removed the wall between the remaining two battery compartments (easy to do, using a pair of side-cutters) to make a
space for the EZ-Key module - http://imageshack.com/i/exq1MkyDj .
Setting aside the battery holder, I turned my attention to the pedals themselves. The wiring between the individual pedals
is underneath and covered with a piece of sticky tape. I removed one, only to discover that these are actually flat printed
strips - http://imageshack.com/i/f0ya1BtZj . I wasn't expecting this, but it didn't seem to be a problem.
Then, I took the pedals themselves apart. This is done by drifting out the pin at the rear of the individual pedals. At this
point, I got a real surprise. I had assumed the pedal operated a mechanical switch, taking them apart revealed they were
actually optical - http://imageshack.com/i/hluO405ij - oh dear, re-think time!! After this initial surprise, I could see
there was actually an advantage to this - I could retain the USB facility, should I ever need it. For the moment, I de-
soldered the USB wiring, making a note of what colours went where - http://imageshack.com/i/f0vGwCVrj - at a later date, I
will re-connect this cable, much shortened, so it doesn't get in the way. If needed, I can use a M/F USB extension cable to
connect to the tablet.
A quick rummage in the 'bits box' found a couple of microswitches (probably liberated from a defunct mouse). These were
temporarily glued into position - http://imageshack.com/i/pcahqTooj - and wires connected to the NO contacts. A similar
conversion was made to a second pedal (I will do the third one when I find a practical use for it). All the wiring was run
underneath the pedalset (using very thin wire) and re-taped.
The battery box was attached to the baseboard of the pedalset, using a couple of nuts and bolts, and another hole was drilled
to pass the new wires through - http://imageshack.com/i/p5SzcyXyjhttp://.../p5SzcyXyj - all that was required
was to solder the wires to the E-Key module - http://imageshack.com/i/p50yUglbj .
The finished job is here - http://imageshack.com/i/pd7IYEX5j - the battery box protrudes slightly over the baseplate because
the on/off switch is underneath. I elected to mount it this way to make battery changing easier.
For the future, all that remains is to fix the microswitches permanently in place with a couple and nuts and bolts (I can't
rely on superglue as a permanent solution) and re-connect the original USB wiring, so that the pedals may be used either
wired or wireless. When I find a practical use for the third pedal, I'll add the necessary wiring.
Total cost has been around €45 - well below the price of a commercial unit.
Being a cheapskate, I had originally opted to use a USB pedal, as they were a lot cheaper (and, I suspected, more reliable).
However, continual plugging and unplugging of my pedals seems to wear out the connector and I began to realise there were
some advantages in having a wireless solution. Commercial pedals are not cheap, so I thought it might be a good idea to start
off with what I already had and see how it went.
Up until now, I have been using a three pedal unit like this one - http://imageshack.com/i/eyWhSoUFj - these are on the net
at around the €20 mark. Actually, they work well, but my problem was the connectors on my tablet, they are really poor
mechanically and have become very intermittent over the past 18 months.
Initially, I started off with the idea of modifying a Bluetooth mouse, but I had a lot of problems with these things timing
out and that was something for which I never found a solution. Someone else on the forum had already mentioned the Adafruit
EZ-Key - https://www.adafruit.com/product/1535 - and this seemed like a good starting point, so I bought one.
Having received the EZ-Key module, I set about modifying the pedals.
The EZ-Key runs on anything from a 3v supply upwards. I use 3.7 volt lithium batteries to power my Casio midi guitar, so I
already had a number of these to hand. One AA size battery is sufficient to power the EZ-Key. I needed something to house
both the electronics and the power supply, so I purchased a switched 3AA battery holder - http://imageshack.com/i/paCkuLwwj -
modified as follows.
As supplied, the battery holder looks like this - http://imageshack.com/i/exWdgsuGj - and my first move was to alter it to
accept a single AA cell. This was quite easy, all that was needed was to remove the connecting links between the separate
compartments, cutting one in half to provide the positive connector for the single battery compartment that was left -
http://imageshack.com/i/ipluJWV9j . The positive connector that remained was a little 'loose', but I decided that the spring
of the negative connector was enough to keep the whole thing in place. You could glue it in place, if you really thought it
was necessary.
A quick check with a voltmeter was made - http://imageshack.com/i/idJP2eH2j - just to make sure the power (and switch) worked
as expected.
Next, I removed the wall between the remaining two battery compartments (easy to do, using a pair of side-cutters) to make a
space for the EZ-Key module - http://imageshack.com/i/exq1MkyDj .
Setting aside the battery holder, I turned my attention to the pedals themselves. The wiring between the individual pedals
is underneath and covered with a piece of sticky tape. I removed one, only to discover that these are actually flat printed
strips - http://imageshack.com/i/f0ya1BtZj . I wasn't expecting this, but it didn't seem to be a problem.
Then, I took the pedals themselves apart. This is done by drifting out the pin at the rear of the individual pedals. At this
point, I got a real surprise. I had assumed the pedal operated a mechanical switch, taking them apart revealed they were
actually optical - http://imageshack.com/i/hluO405ij - oh dear, re-think time!! After this initial surprise, I could see
there was actually an advantage to this - I could retain the USB facility, should I ever need it. For the moment, I de-
soldered the USB wiring, making a note of what colours went where - http://imageshack.com/i/f0vGwCVrj - at a later date, I
will re-connect this cable, much shortened, so it doesn't get in the way. If needed, I can use a M/F USB extension cable to
connect to the tablet.
A quick rummage in the 'bits box' found a couple of microswitches (probably liberated from a defunct mouse). These were
temporarily glued into position - http://imageshack.com/i/pcahqTooj - and wires connected to the NO contacts. A similar
conversion was made to a second pedal (I will do the third one when I find a practical use for it). All the wiring was run
underneath the pedalset (using very thin wire) and re-taped.
The battery box was attached to the baseboard of the pedalset, using a couple of nuts and bolts, and another hole was drilled
to pass the new wires through - http://imageshack.com/i/p5SzcyXyjhttp://.../p5SzcyXyj - all that was required
was to solder the wires to the E-Key module - http://imageshack.com/i/p50yUglbj .
The finished job is here - http://imageshack.com/i/pd7IYEX5j - the battery box protrudes slightly over the baseplate because
the on/off switch is underneath. I elected to mount it this way to make battery changing easier.
For the future, all that remains is to fix the microswitches permanently in place with a couple and nuts and bolts (I can't
rely on superglue as a permanent solution) and re-connect the original USB wiring, so that the pedals may be used either
wired or wireless. When I find a practical use for the third pedal, I'll add the necessary wiring.
Total cost has been around €45 - well below the price of a commercial unit.
Graeme
1: Samsung 12.2" SM-P900: Android 5.0.2
2: eSTAR GRAND HD Quad-Core 4G 10.2": Android 5.1
Some of my music here - https://www.soundclick.com/graemejaye
1: Samsung 12.2" SM-P900: Android 5.0.2
2: eSTAR GRAND HD Quad-Core 4G 10.2": Android 5.1
Some of my music here - https://www.soundclick.com/graemejaye
