JTEX
Well-known member
Here's a little step-by-step tutorial explaining how to make a low profile, no contact, smoooooth feeling magnetic footswitch that should outlast us all. It took me a while to come up with this process, but it turned up so well that I feel it's worth sharing with the community.
1. Start with a footswitch actuator (Alpha SF12030F or similar). They're like momentary stomp switches minus the actual switch part. I found mine at Banzai Music. I'm sure there are other sources:
2. Take it apart (unscrew the bottom cap):
3. Inside you'll find a large conical spring, as well as a plunger with a little spring attached to its bottom nib. Remove the little spring. Cut (or grind off) the nib end, shortening the plunger to 11mm, with a flat bottom. I used a Dremel with a cutoff wheel.
(side note: the plunger and little spring are meant to work with a tactile switch on the PCB, as in some Line 6 pedals. In practice, it does not seem to be a very reliable combination -- they've had quite a few field failures. We can do better).
4. Glue a 4x1mm disc magnet (eBay, Amazon..) to the bottom of the plunger using epoxy (not crazy glue, it won't hold well). Make sure both the plunger and magnet are squeaky clean and degreased before epoxying them together. Use pure alcohol or acetone to clean/degrease. Don't touch them with your bare oily fingers once they're clean.
5. Put the actuator back together. When pushed all the way, the magnet should be flush with the bottom:
6. Your pedal PCB will need to have a reed switch installed just under the magnetic actuator. Do not center the magnet above the reed. It should be above one of the reeds' ends for proper operation:
7. Of course, you'll need some simple logic circuit on your board to take the momentary reed switch input and use it to toggle a latching relay that does the actual switching.
(8) Dear Alpha or somebody, if you're reading this, will you please just make this part, so I don't have to? Thank you!
1. Start with a footswitch actuator (Alpha SF12030F or similar). They're like momentary stomp switches minus the actual switch part. I found mine at Banzai Music. I'm sure there are other sources:
2. Take it apart (unscrew the bottom cap):
3. Inside you'll find a large conical spring, as well as a plunger with a little spring attached to its bottom nib. Remove the little spring. Cut (or grind off) the nib end, shortening the plunger to 11mm, with a flat bottom. I used a Dremel with a cutoff wheel.
(side note: the plunger and little spring are meant to work with a tactile switch on the PCB, as in some Line 6 pedals. In practice, it does not seem to be a very reliable combination -- they've had quite a few field failures. We can do better).
4. Glue a 4x1mm disc magnet (eBay, Amazon..) to the bottom of the plunger using epoxy (not crazy glue, it won't hold well). Make sure both the plunger and magnet are squeaky clean and degreased before epoxying them together. Use pure alcohol or acetone to clean/degrease. Don't touch them with your bare oily fingers once they're clean.
5. Put the actuator back together. When pushed all the way, the magnet should be flush with the bottom:
6. Your pedal PCB will need to have a reed switch installed just under the magnetic actuator. Do not center the magnet above the reed. It should be above one of the reeds' ends for proper operation:
7. Of course, you'll need some simple logic circuit on your board to take the momentary reed switch input and use it to toggle a latching relay that does the actual switching.
(8) Dear Alpha or somebody, if you're reading this, will you please just make this part, so I don't have to? Thank you!
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