DIY Leather Pads - How to Make Sound With Leather and Piezoelectric

Welcome to the first part of my experimental mini-series of:

"How to make sound with XXX and piezoelectric"

Since I'm kind of obsessed with musical instruments and while playing around with my trigger module and pre built drum pads, I've always deeply wanted to make piezo-triggered pads from any material (or combination of materials) I think would be interesting and fun to try out and pads wouldn't usually be made of - starting with Leather.

And because I've had a lot of conceptions in my mind - which basically have similar work steps - I decided to summarize two of them in one Leather-Instructable.

Step 1: The Things I've Used

• Leather pieces (different types, thickness and color)
• Leather Straps
• Piezo Triggers
• 6.3 mm female Mono Jacks
• Washer/spanish Coin
• Glue (contact glue, hot glue, super glue)
• Cellular Rubber
• Soldering Tin
• PLA Filament (black)
• Acrylic Paint (black)
• Flexible Tube
• Book Screws
• Neodym Magnets

• Sissors/Cutter
• Wire Stripper
• Electric Drill
• Soldering Iron
• Rotary Tool

• Trigger Module
• Instrument and Audio Cables
• Headphones, Speaker
• Voice recorder
• 3D Printer
• Mixer - optional

• Tinkercad
• IdeaMaker
• Paint.net
• Digital Audio Workstation (DAW) - optional

additional instruments:

• Cajon
• Snare-Drum-Pad
• Kick-Pad
• Rods

Please take all necessary safety precautions while working with heat, sharp objects, electricity, vapors or resulting gases, noise, bright light and whatever could endanger your health.

Step 2: ​The Leather

I ordered different pieces of leather (thin, thick, black, coloured) from a nearby saddlery shop. These are remnants/leftovers (of the furniture and/or clothing industry, I guess).

The shop offers:

• eco-friendly mineral tanning
• compliance with the PCP Prohibition Rules
• production in an environmentally friendly manner
• free from prohibited AZO dyes

ds-leder Saddlery Shop (Germany)

ds-leder Saddlery Shop (amazon Germany)

Step 3: The Piezo Discs

I ordered a pack of 15 Brass + Copper + Aluminium Wire Base Piezo Discs from amazon.

• Diameter: 27 mm,
• Thickness: 0.40 mm
• Wire Diameter: 1 mm
• Wire Length: 33 cm

Acoustic Pickup Piezo Discs (Germany)

Step 4: ​The Leather Cymbal Pads

4.1 The Concept

My concept is based on playing the leather cymbal pads foremost with rods or by hand while mounted on a cymbal stand as a supplement or extension for a mini e-drum set or a cajon. It's not meant for the "heavy hitters".

4.2 The Shape and Prototypes

The size and shape of brass or bronze cymbals affect the sound. In my case by triggering the sound, the size and shape are just optical elements. So I decided to go for two sizes and a kind of a pizza-slice shape.
I designed a 2D model in Tinkercad and also made two paper prototypes to figure out the final design and where to add the piezo disc, jack connection and the port for the cymbal stand. The paper models also acted as templates. I transferd the shape to the leather pieces, drilled holes in the pull-up/saddle leather and glued on four magnets in each case and the piezo cables to hold everything in place.

4.3 The Jack

I've connected the cables to the jack by soldering. Please don't forget to put on the tube and the jack cap before soldering.
At least I hot glued two magnets in each case to stick the jack as adjustable as possible on every side of the pad. That was the idea in principle, but in practice I figured out, the magnets weren't strong enough to hold the weight of the jack and the cable.

4.4 The Assembly

Because of the thick layers all together I decided to glue the parts with contact glue.
I've glued

1. the cellular rubber and a thin leather piece
2. the first part and the thick pull-up/saddle leather
3. the second part and a thin leather piece.

I've waited 24 hours in each case to achieve the final setting of the adhesive.

To be honest, my first design didn't visually and esthetically worked out as well as I 've expected, so I ended up with this three layer design. It's presumably not necessary but makes it very sturdy on the other hand.

4.5 The 3D Printing

While working on the knee pad I had various ideas to attach the small cymbal pad to my knee as well, like using velcro or magnets. A closer look at the attachment to the cymbal stand led me to go for this kind of mounting. I made a quick design in Tinkercad and 3D printed the parts in black PLA-Filament. I painted the top part with black acrylic paint and attached black adjustables leather straps to the bottom to fasten the pad to my knee; the straps are closed via a sling, a washer and a knot.

Step 5: The Leather Knee Pad

5.1 The Concept

My concept is based on playing the leather knee pad by hand while mounted on my knee as a supplement or extension for a cajon.

5.2 The Shape and Prototype

I went for a belt-like shape(ca. 28 cm x 6 cm).

I designed a 2D model in Tinkercad to figure out where to add the piezo disc and jack connection.

5.3 The Jack

I've used a female 2 pole open 1/4'' jack with 2 contacts, washer and nut.

5.4 The Assembly

For fixing the jack, I drilled a hole into the leather and connected the cables to the jack.

I've attached the leather parts with book screws, which I highly recommend.

To cover the piezo disc from the back side I glued the cellular rubber onto the leather. The cellular rubber makes it very grippy so the pad won't get out of place. I've waited 24 hours to achieve the final setting of the adhesive.

I attached brown adjustable leather straps; the straps are closed via a sling, an old spanish 25 pesetas coin with a centred hole and a knot.

Step 6: ​The Sound Tests

After each process step, I performed a sound test. It would have been very annoying to find out after assembly that the piezo trigger has been damaged.

Step 7: ​The Trigger Module and Sounds

The Trigger Module (TM-2) has two stereo trigger inputs. Via splitter cables the two stereo trigger inputs can be splitted into four mono trigger inputs to connect two more pads - for example a kick bass pad and a snare drum pad.

Instead of using the built-in Cymbal/HiHat sounds, I've placed the audio files (WAV) of the DAW Reason 10 Lite in the folder of the SD card, inserted the SD card into the TM-2's SD card slot and assigned the audio files to the pads. By striking the pads you can play WAV-files, like drum sounds, sound effects, songs or loop phrases as well.

Connecting the TM-2 to a mixer isn't actually nesseray. Well, I have the mixer, I use the mixer.

Step 8: The Leather Cymbal Pad Mini E-Drum-Set Up

I've connected the Leahter Cymbal Pads, a snare drum pad and a kick-pad to the TM-2 and the TM-2, speaker, headphone and voice recorder to the mixer via cable.

The sound was recorded by the mixers OUT to the line-in of the voice recorder.

Please take a look at my short video and excuse my bad timing; I'm working on it.

Step 9: The Leather Knee Pad Cajon Set Up

I've connected the knee pad to the TM-2 and the TM-2, speaker and headphone to the mixer via cable.

The sound was recorded by the built-in microphones of the voice recorder.

Please take a look at my short videos and excuse my bad timing; I'm working on it.

Step 10: Thank You …

... for reading, watching and paying attention.

As always it was a great learning experience and most of all an example for

• having patience and
• taking the time to reconsider and reinvent at one point or another.

What would I do different next time?

The magnets turned out to be an inappropriate attachment for the jacks because - as I mentioned before - the cables are too heavy. I would try to find another solution for that.

Please let me know if you've made one by yourself.

Hopefully Auf Wiedersehen in one of my next instructables.

Comments

[Cherzer]

Question: Do the Piezo Triggers act as say a button, with a single discrete signal per strike, or are they more like a microphone, which can pickup a multitude of little variations in the strike?

[alleshochladen]

In my understanding I would say every strike sends a signal to the trigger module. The recognized intensity of the strike is adjusted by the sens and threshold in the module's trigger settings. If the threshold isn't set correctly you will receive double/multiple triggers by just one strike or no triggering.

[Ham-made]

Hallo alleshochladen!
Superb use of piezoelectric elements! I'm a high school art and music teacher/tortured artist and I've been making, modifying, and amplifying instruments for years. I had an idea for a potential additional trigger for your cajon setup and have included some images that I quickly modeled up. You wear it sort of like a slipper or sandal and activate the trigger by bringing down your heel. If you observe yourself playing your feet are already in the perfect position!
Mach weiter!
Mr. Ham

[alleshochladen]

Hello Mr. Ham,

thank you for you kind words. Your sandal/slipper pad looks very interesting and close to my design; I've already made a food pad, but unfortunatly it doesn't work. The sound tests have been OK, but after the final assembly it puts out none or multiple sounds, maybe I've damaged the piezo disc. I've already taken it appart as carefully as possible and now I'm trying to find out what went wrong.
I will document this process as well and will upload it if this thing
finally ever works proper. I will go on!

Bye, alleshochladen

[Ham-made]

Sounds like a loose solder joint! Sometimes the soldered joint on the crystal slurry of the piezo element (the inner disc) will tear off the coating and become disconnected without showing any visible sign of disconnection. If that is the case, simply re-solder the connection to a different part of the inner disc. Another tip that I've picked up over the years is to sandwich the piezo element, once soldered, between two pieces of a harder material. In your case, using two larger squares of leather would be perfect for this! Use a bunch of hot melt glue to ensure that the connections remain in place and your piezo element will be a lot less susceptible to becoming damaged by regular wear and tear. Good luck! One last thing, sometimes replacing the piezo element entirely is the only way to get things operational again, but should be a last resort.
Cheers!
Mr. Ham

[alleshochladen]

Thank you. I followed your suggestions. Frist I've sandwiched the piezo between two pieces of a harder material (because the material of the pad is very soft, too soft!) - without success. Than I re-soldered the connection to a different part of the inner disc and sandwiched it again - same wrong results, unfortunately. Because of the soft pad material and thin leather cover (contact glued together) I decided to start over again with a more harder, solid foundation. This is part of the learning process, I guess.

[john pedersen]

Amazing sound, I wouldn't have expected that, great job!

[alleshochladen]

Thank you very much.
I'm still working on the sound recording and sound editing . I usually only
accompany the videos with background music; mostly made in Reason 10. The
Reason sounds are so great in my opinion.