$15 Foot pedal left mouse button project

I used to do 3D animation and devloped tendinitis in my right index finger from using the mouse so much. Normally, it’s not too bad, but it can be painful sometimes. I tried different sized mouses, trackballs, etc. but clicking the left mouse button always hurts. Trackpads are a solution, but I just like the feel and accuracy of a mouse. Anyways, I found the Fentek foot pedals, but being the cheapskate that I am, I was unwilling to part with $95 for a foot-operated mouse button.

After thinking about it for a while, I came up with the idea that I could hack the components of an old mouse with a foot pedal used for electronic keyboards. The switch used in these type of pedals are normally open and momentarily closed when depressed…essentially a foot-operated mouse button. I was able to put a working unit together for about $20 and here’s how I did it:

Parts List:

  1. M-Audio SP-1 Sustain Pedal I found it for $15 online, plus shipping
  2. A USB mini-mouse. One of those tiny ones that usually come with a retractable cable. I got mine as a freebie giveaway from somewhere. Here’s a Amazon link, but I’ve seen them on eBay for $5.99 with free shipping.
  3. Pliers
  4. Soldiering iron
  5. Electrical tape
  6. 2-conductor wire. Only a couple inches needed and you could get away with using the existing wires in the foot pedal.
  7. USB extension cable, if your PC doesn’t sit on the ground

First, disassemble the mouse and take the circuit board out of the shell. Mine had a pair of screws on the bottom. (One screw was beneath a sticker.) The scrollwheel should just come off, but be careful not to disturb the cable wiring. You can disgard everything except for the circuit board and the attached USB cable.

You can either de-soldier the three little switches and the scrollwheel mechanism or just carefully snap them off by rocking them back and forth with pliers. I took the latter route.

Open up the foot pedal by unscrewing the two screws on the left and right sides. The spring will be loose so be careful not to lose it. Save these screws and spring in a safe place. Also remove the screw in the bottom left corner of the circuit board (see picture). You can disgard this one screw. The mouse circuit board will lay over this area and you need the space and also don’t want that metal screw shorting anything out.

Now, you can either carefully bend the back corner in to make an exit for the USB cable or you could drill/dremel an opening. I was lazy and don’t have a dremel, so I just bent it in with pliers.  Note that if you bend it you need to be careful because the pedal cover is screwed into the side and you don’t want to get it out of alignment.

Next, soldier the wires to the two soldier points that are used by the right-mouse button. Soldier the other ends to the foot pedal circuit board. One conductor where the red wire is connected and the other conductor to where the black wire is connected. If you want, you can remove the foot pedal wires, but it’s not required. Cut off the big cable attached to the foot pedal circuit board and disgard.

[The soldier points and the screw removed]

[A bird’s eye view of everything]

Now, orient the mouse circuit board along the left space of the footpedal with the IC facing up. It won’t totally fit and some of it will lay over the pedal board circuit board. You’ll need to move the wires around the foot pedal board so that the mouse board can lay as flat as possible.

[Route the wires in the cavity around the foot pedal board]

[The mouse board should not protrude (much) above the top of the case.]

You can plug the USB cable into your computer and test the switch now. Just press down on the rigid wire on the foot pedal board. If it doesnt’ work, check your wiring. It’s very basic circuitry. When the rigid wire is depressed, it completes the circuit. When not depressed, the circuit is open.

Once it all works as expected, put some electrical tape over the top of the mouse board to ensure no shorts occur when the pedal is depressed. Put the spring back in it’s place. Screw the top of the pedal back on.

One downside of using the mini-mouse is that the retractable cables tend to be on the short side. Thus, I had to use a USB extension cable for the unit to reach the ground. You may not have this issue if your PC sits on the ground, but I’m using a laptop.

Well, all in all, it’s a pretty quick and easy project. The mouse was a freebie I got somewhere and so the entire project only set me back $20 including shipping on the $15 pedal. It is probably a little more “springy” than I’d like it to be, but maybe it will loosen up over time. Enjoy!

Follow up

Comments 13

  • I just tried this and the mini mouse circuit board was too big. Do you or anyone have the manufacturer and part number for one that actually worked? Thanks.

    • Ken, there is a link in the post to Amazon that will show you the type of mouse i used. Here’s the link again Mouse link

      • Hi, I saw the link but I decided to use a better mouse with a decent cable. I kept the mouse board external to the pedal. It works great. I improved it with a more delicate spring I bought at the hardware store. All you do it tap it for a click. Thanks for this idea!

      • Your welcome. Nice job!

  • I am trying to find a foot mouse to run the power point presentations for lyrics . I have not looked yet. but if I used the right side of the mouse to change screens ,it would work the same only using the right wires? Right?

    • John: Yes, if you use the wires for the right mouse button, instead of the left button wires, it will generate a right mouse click. I think that’s what you are asking.

  • Does the foot pedal hold the weight of your foot/leg or do you have to lift your leg up and place your foot on the pedal each time to click?

    Thanks in advance,

  • I just built one of these using your instructions. It worked out great. On the old mouse I used, the other end of the USB plugged into the circuit board so I was able to snake that through the existing hole (after widening it just a bit). The MAudio pedal I used was a little bit different as well (maybe a new model) – I got it for $15 with free shipping on Ebay. They’ve removed the circuit board with a simple tiny switch inside. This allows for a little bit more room which was perfect since the old mouse I was using was a standard sized mouse (not a micro mouse) but I was able to fit it inside anyway. Anyway, thanks for posting this, it worked out great!

  • @Jody: I sort of doubt it. The only reason that this mouse worked was because the circuit board was very small. I assume a full-sized Apple mouse would have a much larger circuit board and, thus, would not totally fit inside the pedal. HOWEVER, if you didn’t mind how it looked, you could put the circuit board outside the pedal and run the wires inside. Maybe, you could mount some wood as a base under the pedal and hide the board in there or something like that.

  • Can you do the project with an apple mouse? I have an extra one, and this is exactly what I need to use for my one-man musical ensemble and changing the page of lyric sheets using keynote.

  • I have to say, I could not agree with you in 100%, but it’s just my IMHO, which indeed could be wrong.
    p.s. You have a very good template . Where did you find it?

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