# Designing a 1-button system allowing for a differentiated control of 2 different valves?

I'm in the processes of building something which requires I'll be able to control the independent opening/closure of two (small, ~10mm in diameter) different adjacent holes using one finger, and I'm trying to think of ways such a thing can be put together.

The movement required from the finger shouldn't be too convoluted, so my original vision involves having the two holes open when there's no pressure applied to the button, and then when the button is pressed half-way through it closes only one hole while when it's pressed all the way down it closes both holes.

The control in such a situation might be tough to perform with accuracy, so my other idea involves having the button's resting position rather at the middle of the available movement, allowing it to be moved up or down while the middle position leaves only one hole open, the upper position opens both and the lower position closes both (in this case the "button" won't be a button but rather a "cup" of sorts you can place your fingertip into).

The closed-open combination is unidirectional, so the possible closure patterns required are either both hole¹ and hole² open, hole¹ open and hole² closed, or both closed, but no requirement to have hole¹ closed while hole² is open. They should be able to close the holes against the air pressure of exhalation (or less actually as there would be ventilation elsewhere).

I think the hole-closing structure itself would involve padded surfaces dropping onto each hole to cover it.

Any tips how could such a mechanism be built?

EDIT (additional info): I think some further clarification is required. The holes would be situated on a cylindrical surface. The controller should be placed at 90 degrees to the two holes (so it doesn't continue in the same line of direction), and the closing surfaces should open plenty so there's no obstruction in air flow, and possibly open to the side opposite the controller. Here's a rough sketch:

Obviously this is not an actual mechanical design, just guidance for the wanted form.

• You say "independently control", and then describe Open-Open, Open-Closed, and Closed-Closed, but not Closed-Open? Is this OK? Jul 11, 2019 at 12:15
• Is this a fully mechanical system? Do the holes need to seal against pressure or just 'look closed'? - we need more information!! Jul 11, 2019 at 12:16
• @Jonathan R Swift Oh, I should clarify. The closing required is only in one order. So if we have hole¹ and hole², I need to have the option to either have both hole¹ and hole² open, or hole¹ open and hole² closed, or both closed, but no requirement to have hole¹ closed while hole² is open. They need to seal against air pressure, but I don't think a significant amount of down pressure would be needed from the closing mechanism. We're talking about the air pressure of a exhalation, and it could be divided among 1 to 12 (most likely) such holes if all are closed.
– TLSO
Jul 11, 2019 at 12:35
• I'm very close to recommending closing this question because it is difficult to understand what you are asking. Your first line is poorly expressed, "...which requires I'll be able ...", doesn't make sense. The other thing you do not mention is the orientation/layout of the holes. Are they to be located on a flat surface or in a tube. I'm envisaging what you want might be achievable if the holes were in a tube & a value inside the tube can block one or both holes. Could you please clarify you question.
– Fred
Jul 11, 2019 at 14:08
• @Fred The holes would be on a tube. The holes would probably be facing up, but that might not true for all of them and either way, the closing mechanism shouldn't be moved by gravity. The reaction should be fairly quick and I suppose it would be fitted with springs.
– TLSO
Jul 11, 2019 at 14:33

Similar mechanisms exist on some musical instruments (saxophone or flute). You have two small buttons attached to levers, button 1 closes hole one, button 2 closes hole 2. Both are adjactant, so the finger can easily slip from one to the other. To achieve your requirement, button 1 is equipped with a small cam that is also pushed by button 2 (but not vice versa).

Several ways of doing this:

Either you add a small cam to the lower side of one button so the other button pushes that cam downward. Or you add a cam to the lever connecting the cup (the part covering the hole) to the button, so it pushes on the other lever. You can also add that cam to to the cup, so it acts on the other cup directly. These varaitions all achieve the same function: press on right button to close only one hole, press left button when closing both holes.

I'm pretty sure you'll find all three variations and then some on a concert flute or saxophone, but to be frank I'm to lazy to snap and post pictures right now.

• I actually want to make this for use in a planned home-made flute of sorts. The systems I researched for modern flute or saxophones don't work by having an actual individual finger-controlled button for each hole, as there are usually significantly more holes to be controlled (16 or 17) than human fingers, so from what I gather doing different cross-fingering patterns (where keys aren't lifted in a direct sequence from the end of the flute) dictates through whatever mechanism different closure patterns of the holes. There might also be buttons control with the palm's side or occasional ...
– TLSO
Jul 11, 2019 at 22:04
• ... position changes, I'm not certain as I don't play woodwinds, but the point is that I didn't see the design you mention here. But now that I looked again I saw something on the concert flute I didn't notice before: it seems at least in some designs, some of the keys have open holes in them (they are a ring, basically), and pressing them also controls a closed-hole key (so I figure). Looking at examples, they don't do the exact movements I have in mind, but perhaps still making a series of remote-controlled closed keys and then open-holed buttons would be easier and make more sense.
– TLSO
Jul 11, 2019 at 22:13
• I played. Saxophones have groups of (I think) 4 buttons for the lower notes that work similarly, but I didn't find a good picture yesterday. With the cams you'd only ever need to press one button at a time.
– mart
Jul 12, 2019 at 7:12
• Similarly to what you mentioned? It seems a saxophone does have more buttons than a flute, but I'm not sure this type of design would be effective enough for a flute. I think what I noticed (or thought of, I don't know if it's exactly how it works) on the concert flute, as mentioned in my previous comment, with some buttons functioning both as open holes (closed by fingertips) and as controllers for other closed keys, is the most logical design in terms of building ease and performance. I still don't know what the actual design would involve, though.
– TLSO
Jul 12, 2019 at 8:13
• See answer, I've added a picture of what I meant.
– mart
Jul 12, 2019 at 8:54

Lets say we have the hole two 3cm on the left side of the hole one and both on the surface of the exhale chamber.

You can have a 10cm long lever, hinged on the left side of hole 2 and a few centimetre to the left of it, making it possible for the lever to swing up and down around the hinge. On this lever you secure two sealing caps at appropriate location wrt to the two holes.

These two caps once the lever is lowered will first block hole 2 and then both holes and lifting it back up will first open hole 1 then both holes.

This lever is attached on the other end to your finger cup which is secured in place by a simple spring and a guide groove with three positions.

• Position one , the lever is in the middle, holes 1 is open.

• Position 2, the lever is down both holes are closed.

• Position3, lever up, both holes are open.

EDIT

I added a diagram after OP's comment.

The default position of the lever is when hole 1 is open. you could change the positions as it may work better for your task. The rubber sealers are flexible and compressible.

• I'm sorry, but I don't think I understood what you're training to explain... But I will say I think my preferred method of control would be was I mentioned in the second option, where the controller can move up or down while the lever rests in the middle position (where it's hole¹ open and hole² close).
– TLSO
Jul 11, 2019 at 16:44
• @TLSO, I added a diagram. It should help clarify what I mean. the rubber sealer must be compressible or mounted an a flexible support to allow a bit of play. Jul 11, 2019 at 17:38
• Oh, perhaps I should have clarified even further. I believe it's important the vents would open plenty so there's no significant obstruction in air flow. Like this I think it could affect it too much. I'll try to add a photo to my question showing what I envision. Thanks either way.
– TLSO
Jul 11, 2019 at 17:53