For decades drummers with a do-it-yourself attitude have been designing and building their own electronic drums. For those of you who are not familiar with this unique hobby, it is actually very simple to build a basic electronic drum, and the advantages are many. For many drummers there are two main obstacles to owning a drum set. One is that they live in a residential area where an acoustic drum set would be much too loud, and the other is the high cost of electronic drum sets. Building your own electronic drum set solves both of these problems, and can be very rewarding and satisfying. In fact, when properly designed, a high quality drum set can be built for around $200, including the module. Compare this to a similar kit which would cost over $1000 new, and the value in building your own becomes evident. For many drummers this is the only way to afford a kit, and for others the fun in building it is their main motivation. Furthermore, building an electronic drum set allows you to customize it to your needs, or even build a very large kit that would be very expensive when purchased new.
The first step in constructing electronic drums is to purchase a MIDI module. The module is the brain of the electronic drums, and being such, is the one piece that would be difficult to construct yourself (although not impossible if you have electronic know-how). In keeping with the thrifty attitude most do-it-yourselfers posses, used modules are a great alternative to higher cost now models. For countless drummers the Alesis D4 has been the standby for electronic drumming. Because so many of them are in existence, and because of their high quality design, it is very easy to find a used model for sale on Craigslist or eBay. Expect to pay around $100, although with enough searching units can be found for less.
The next step is to construct the drums. Aside from the module, the other key component of electronic drums is the trigger, which is merely a piezo transducer. A piezo converts vibrations into electrical signals, providing a velocity-sensitive response. In other words, a piezo converts the drum hits into electric signals that get sent to the module, where they are converted into an output sound wave that can either be played on an amplifier or through headphones. Piezo traducers are very low cost and easy to find. The most common piezo among hobbyists is Radio Shack model 273-073, mainly because Radio Shack is the most common store to purchase electronics, and the part only costs a few dollars. This model is encased in a plastic case that must be removed. A better option than Radioshack is an online supplier of piezo traducers that are not encased. The online electronics vendors will always be cheaper than Radio Shack, and save you the trouble of cracking open the electronic case, which can be tricky to do without damaging the piezo.
Once the piezos are purchased, the next step is to construct drums. This is where you can be very creative. There no limitations to your design, you merely need to mount the piezo under some soft of surface that represents a real drum head. The most common heads on electronic drums are rubber or mesh, although anything that can be struck and transfers the vibrations to the piezo will work. In fact it would be possible to build an entire drum set played with only the fingers tapping directly on the piezo. Rubber heads are very common in do-it-yourself designs because they are very simple to make. Mesh heads offer the advantage of a quieter and more realistic feel, however. With more patience and a good design, high quality mesh head electronic drums can be constructed out of common materials and at a very low cost. For many people the most satisfying part of such building projects is using everyday materials.