Salvaged mechanics part 2 – the Hi-hat

The Hi-Hat

(follows from here)

This is something I am really proud of. Enjoy!

Here you can see how the final assembly looks like. I wanted to make a hi-hat as close as possible to the real thing. This time the ingredients list is:

  • The top and the bottom of a beans can. This gave me also the inspiration for a delicious pasta e fagioli. (Excursus: also Dean Martin sang about Pasta e fagioli in his famous “That’s amore“. It’s interesting that the English Wikipedia says that this dish is typical in Venice, while the Italian one states that it’s typical of many regions of Italy. I agree, it´s not only venetian);
  • A spare part of my bicycle shift (a SRAM S7). Once I broke a small plastic part of my shift, (it´s marked with the number 42 in the picture below). I have bought a new one for 3 or 4€, but in the same plastic bag there were also part 40 and 41. I didn’t need them at that time, but I saved them, you never know… They are perfect for hi-hat mechanics!
    Sram S7 assembly
  • Some electrician screw terminal blocks;
  • Electrician nails, the ones used to attach the cables to the wall;
  • A plumber sealing (or maybe a rubber foot for a chair? Not sure);
  • A broken bicycle spoke, which I have bent and used for the stick;
  • Some M3-threaded screws (I have to admit, I bought those…);
  • Elastics;
  • Omnipresent felt pads and bicycle inner tube for silencing.
On top, the push-type solenoid. When current is applied, the rod moves to the right. On the bottom, the telescopic rod from the bicycle shift. On the background, some poor math.

On top, the push-type solenoid. When current is applied, the rod moves to the right. On the bottom, the telescopic rod from the bicycle shift. On the right, a screw terminal block. On the background, some poor math.

How to build a hi-hat

The issue here was to build a real hi-hat (just to let you know it’s called a charleston in Italian). The hi-hat must be hit by the stick but it must also be able to open and close. This is how I built it:

  1. First of all, I created the “cymbals” with the can parts. I cut and then beated the two lids with a hammer in order to make them conic, and I drilled a hole in the center for the rod. Take care, they can be sharp!
  2. Then I connected the rod of the solenoid to the rod of the shift. The screw terminal blocks were perfect for this! I only wanted to remove the plastic from them.

    Terminal block before and after the diet

    Terminal block before and after the diet

  3. I have cut some of the outer part of the bicycle shift rod, so that the rod was long enough to pass through the two cymbals. I have closed the mechanics on the top with another terminal block. I needed to experiment a little in order to keep the cymbals horizontal and to keep them loose enough to produce a loud sound. I have stacked some stuff like the rubber sealing and some washers in between; the washers make additional sound (noise?) when the cymbal is hit.
  4. I built a lever for the stick with a bicycle spoke. Since the travel of the rod is very short, I had to add an additional elastic here: this will keep the lever always in tension and remove the play of the stick, making every stroke effective.
  5. I put all the elastics for the return effect. In this case it was very easy: the solenoids have M3 holes, and also the terminal blocks do. So it was easy to put long screws and wrap the elastics around them.
  6. For the hi-hat, i really needed to silence the mechanics. Everything can be really noisy, sometimes even louder than the hi-hat itself! I had to use some tricks. This below is the rod that moves in the solenoid. I added that little blue rubber ring (it’s a piece of insulation of a wire). That’s enough to avoid the conical part of the rod to hit the housing of the solenoid.
    Silenced spindle
    I needed to silence it in the other direction, when the rod is pulled back by the elastic. To do so, I put a felt pad with a hole on top of the solenoid. It was not enough, so I put also a piece of rubber taken from an inner tube of a bicycle tire (you can see it on the left)
    Silenced solenoid
    These tricks were only needed for the solenoid which pushes the stick, because it’s used more frequently. For the “pedal” of the hi-hat I only needed to put a piece of rubber between the top cymbal and the terminal block.

In this video you can see what is the final result with a demo song. You can see that there is an open sound, a closed sound, and the “pedal” sound. I think there is also a appreciable dynamic. I will explain in the software part how this is done, stay tuned!

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