DIY Drum Trigger Piezo Transducers

Mesh-type heads and piezo transducers create sound in electric drums.

Electric drums have triggers that convert impact into electricity, which they then send to a signal processor. The signal processor assigns a sound to the charge. Drum triggers function in a very similar fashion to piezoelectric guitar pickups. The piezo element converts the impact of the stick hitting the drum into an electrical charge, in the same way a guitar pickup converts the impact of the strings moving. Because drums and acoustic guitars are resonant chambers, microphonic transducers are unsuitable due to the potential for feedback. This is why piezoelectric material is preferable. Making your own drum trigger piezo transducer means you can convert acoustic drums into electric ones.

Things You'll Need

• Coffee can lid
• Rag
• Naphtha-based cleaner
• Coax cable
• Wire cutters
• Speaker cable
• Copper insulation tape
• Heat-shrink tubing
• Hairdryer
• Glue
• Soldering iron
• Solder
• RCA jack
• Drum or biscuit tin and pantyhose to approximate a drum

Instructions

1. Clean the underside of a coffee can lid with a rag and naphtha-based cleaner. This removes all coffee residue.

2. Cut a 5-inch piece of piezo coax cable.

3. Strip 1/8-inch of insulation from one end of the coax cable.

4. Strip all three tips of the speaker cable. One end of the speaker cable is split in two, with one negative and one positive end.

5. Solder the stripped end of the coax cable to the single-end of the speaker cable. Wrap copper insulation tape over the solder joint.

6. Lay the speaker cable out flat and measure the distance from the copper insulation tape to the double-end of the speaker cable.

7. Cut a piece of heat-shrink tubing to an equivalent length.

8. Slide the heat-shrink tubing over the speaker wire so it covers the copper insulation tape but leaves the coax cable uncovered.

9. Heat the tubing with a hairdryer until it shrinks.

10. Brush a thin layer of glue onto the underside of the coffee can lid. Coil the coax cable and place it on the coffee can lid. Leave the glue to set for an hour.

11. Solder the negative end of the speaker cable to the panel-mount part of the RCA jack. Solder the positive end of the speaker cable to the ring-mount part of the RCA jack.

12. Glue the top of the coffee can lid to the bottom of a drum on your kit. If you don’t have a drum kit, you can fashion a drum-shaped housing for the trigger. For example, remove the base and lid from a cookie tin and wrap pantyhose over the top and bottom. Glue the trigger to the bottom of the pantyhose. The pantyhose approximates the feel and tension of a drum skin, but is silent. This means you can hit the “drum” and the only noise you hear is the sound assigned to the trigger by the signal processor.

Tips & Warnings

• Only solder in a well-ventilated area.

References

• Liutaio Mottola: Constructing an Under Saddle Transducer
• Electronic Drums: Do It Yourself Drum Trigger Pads
• Drum Junction: Discover Drum Trigger Uses- From Traditional to Cutting Edge

Resources

• E Drums: DIY Window Screen Mesh Drum Heads