DIY Drum Pads And Pedal Triggers

Paul White enters Blue Peter mode and puts together a fully working drum pad and pedal trigger system for less than the cost of a pint of lager.

If you own an Alesis D4, drumKAT, Akai ME35T or any other drum machine or percussion controller that accepts external pads, you can't afford to miss this.A deeply anonymous guitarist once said that drummers are the kind of people who throw their used underpants at the wall and wear what doesn't stick. It came as no surprise, therefore, that an equally anonymous drummer later described guitarists as the sort of people who throw their used underwear against the wall and wear it whether it sticks or not. Neither of these statements has a direct bearing on the rest of this article, but with a subject as ruthlessly practical as this one, I though it might help get you into the right frame of mind!

The great thing about the Alesis D4 drum machine (and similar devices) is that you can plug in your own drum trigger pads and bash away just like a real drummer, instead of having to enter drum parts from a keyboard (which is almost, but not quite, as hard as trying to enter keyboard parts from a set of drums!). The less than great thing is that decent commercial drum pads don't come cheaply, and if you're not likely to need them them very often, they probably don't come very near the top of your Christmas list. The alternative is to build your own — but before you protest that DIY isn't your thing, the projects described here are very simple, they work, and they're ridiculously cheap to put together.

The Drum Pad

I know that everyone hates cutting circles out of wood, so the drum pads can be made using old table mats or large drinks coasters. It doesn't really matter what shape they are, so long as they are big enough for you to hit. The pickup is a piezo transducer available from Maplin Electronics for little more than the cost of a Mars Bar, and to make the playing surface a little more comfortable, a piece of thin rubber matting (from a car mat or a vandalised hot water bottle) can be stuck on top using contact adhesive. The pickup is best fixed with silicon rubber, but contact adhesive will do at a pinch.

One problem common to all piezo drum pads is that when you hit one, the vibration may cause the one next to it to trigger. I got around this by using foam rubber spacers (one to two inches thick) to support the playing surface. The base of the pad is another table mat, and if you plan to leave them loose on a table top for playing, I'd recommend you fit stick‑on rubber feet to prevent them slipping. If you want to mount several pads on one board, put another thin piece of foam rubber beneath the pad bases and your board to provide further isolation between adjacent pads.

You do need to be able to solder a couple of wires onto a jack socket, but you don't have to solder leads onto the transducer, because the ones recommended come with the wires already attached.

Beaterless Pedal

Moving onto the pedal, this works on exactly the same principle, except that instead of hitting a pad, a rubber striker hits the back of the transducer directly. This time you will have to saw some wood, though the actual dimensions of the pedal are not critical, providing it's comfortable to use. The moving part of my own pedal is about 10 inches long by four inches wide — 10 or 12mm ply is ideal. The pedal should have around one inch of travel, and a strap should be fitted as shown in the diagram to prevent the pedal opening too far. I used a piece of plastic packing band from a parcel to make a strap, but you could use leather, fabric, or even a strip cut from a Squeezy bottle if you're after true authenticity.

The choice of spring is important, as it should be quite weak; the one used on the prototype was obtained from a hardware shop, and is around 1 inch in diameter and 4 inches or so long when uncompressed. At a pinch, you could probably make your own from piano wire; as long as it is able to return the pedal to the starting position fairly smartly, it will do the job. Because I counterbored the wood using a 1‑inch wood bit, the ends of the spring are quite secure without the need for further fixing.

The piezo transducer is glued brass side up to a small piece of foam rubber, and arranged so that when the pedal is fully depressed, the transducer and foam are pushed down around an eighth of an inch. The output from the piezo transducer depends on how hard it is struck, so both the pad and pedal are velocity‑sensitive. For best results, you may have to adjust the sensitivity of your drum machine or trigger unit, and if you're still not getting enough output, try sticking a drawing pin into the end of the rubber striker. Figure 1 shows how both the pad and pedal are put together, and as you can see, neither is a great feat of high technology. To prevent the pedal slipping, you may want to fit a couple of spikes. If you're really sophisticated, you could buy a pair of 'fit‑it‑yourself' hi‑fi speaker spikes, but if you're into low‑tech solutions, bang a couple of nails through the base board, so that the points just protrude!

Beat It

Because the pedal described above doesn't have a beater, it inevitably lacks the responsiveness and bounce of a real pedal hitting a real drum, and while this may not matter to the keyboard player wanting to enter the odd drum part, it might not be considered 'fast' enough by drummers. In this case, a pad system that can be played using a conventional bass drum pedal may be a better option.

The pad shown in Figure 3 is based on the same piezo pickup used in the drum pad and pedal, and, again, may be used with just about any pad‑to‑trigger converter or drum machine with trigger inputs. Because the pad has to withstand the full force of a mechanical pedal, the transducer is mounted rather differently than in the previous examples, but in constructional terms, there's nothing too challenging.

A simple half‑inch plywood base is used; this provides an anchor point for the pedal, and also gives the required stability. On my version, the base measured around nine inches wide and 14 inches long, but this measurement isn't critical. I was taking no chances with the wooden frame, so I used a couple of bits of 3 by 3 I had lying around, and fastened them together with glue and screws, strengthening the corner with a gusset made from 3/4‑inch timber! Again, the dimensions aren't critical, as long as the top of the upright post comes a couple of inches above the spot where the beater hits.

The pickup pad needs to be fixed to the upright post, so that the beater hits it as near to dead centre as possible, and to afford the piezo pickup some degree of protection while not sacrificing too much in the way of sensitivity, I opted to glue it to a square of quarter‑inch ply, and sandwiched this between two layers of 3/8‑inch neoprene foam. Once glued to the post, I decided to take no chances, and wrapped a few layers of plastic insulation tape around the pad and the upright post to make sure nothing worked loose. This also protects the neoprene, and if the tape starts to wear out, it's easy enough to replace.

Tests using my drumKat MIDI drum controller confirmed that the sensitivity was adequate, and because of the layer of foam in front of the pad, the overall feel was surprisingly close to that of a real drum. Left to its own devices, this pad system will tend to creep along the floor when in use, so it would be wise to fit a couple of spikes to the front edge. No mounting details have been provided for the jack socket, as the user may want to try different options. For example, the jack socket could be dispensed with altogether and a captive lead substituted. The final touch is a spray of matt black paint — unless you want to go for the hand‑waxed pine look.