I wonder how much noise the solenoids will make.

__________________
Bill
Smart Kits build Smart People
http://www.blueroomelectronics.com

 

Same here. By far the hardest part about making automated musical instruments is the fact that most parts you can scavenge weren't designed with taking into account as a perogative how much sound they make during their normal operation. I don't suspect the solenoids will make much sound at all when activated, and as you can see from the concept drawing, their impact on the recorder will be cushioned by a sponge and piece of rubber. They're not moving very far, and they don't have to press very hard against the recorder. The thing I haven't fully taken into account is when they retract from the recorder with the elastic band - there'll have to be some sort of stop on the solenoid at the opposite end of the pin/finger to prevent the pin from jumping/falling out altogether, but again, whatever I use to stop the retraction can be spongy to limit the amount of operation noise.

 

Souper man

Looking good! when can we expect the final product?

If you want to limit the sound coming from the solenoids, why not wrap them in foam or somthing? What about bubble wrap? I dont know what that would do, but its just an idea.

 

As it says in the OP, the end of August, but I'm planning on sharing my progress on this forum for support and advice (so the suspense shouldn't kill you). The timeline is for an autonomous, single recorder playing somewhere close to a first-year student level, but the project will extend beyond the end of this summer to as far as I have the ambition, patience, and resources for. As far as sound insulation for the solenoids is concerned, I'm not going to get too carried away with ideas until I've actually got the things. Provided the pins are machined to fit the casings well, and enough cushioning for the extension and retraction, they shouldn't really need any insulation other than that. Remember, some of the sound from the robot (i.e. the recorder) I want to be able to hear, so that limits the options for sound insulation, and just from an esthetic point of view I'd like to actually be able to see as much of the recorder and the robot's mechanisms as possible (hence, for instance, the choice of acrylic sheet for mounting the solenoids).

 

Souper man

I guess that is the best course of action. It would be better to get everything first and build it before you start thinking of upgrades. How are you going to feed air to it? Through a special pump connected to the mouthpeice?

 

That's right. A length of tube will direct the air into the mouthpiece. A solenoid representing a recorder player's tongue will intermittently interupt the airflow to articulate notes.

 

There's going to be a whole load of mechanical noise coming from that thing not just flute noise =) I'd strongly recommend damping those solenoids with a good spring to avoid noise. No matter what you use for shielding you're not going to be able to damp the low frequency noise. If you use a heavily loaded solenoid (a stiff spring cut to cause it to try to return to a half way extended point would damp the thumps, if you could load the solenoid enough you could eliminate it altogther.

__________________

 

The second page of the 16F88 is the page not easily assessable (0x800 to 0xfff). You can store data using the DW directive and read it back with the EEPROM registers.

This is how I read it in a recent project,
Before calling the above you setup EEADR & EEADRH to point to where you want to read. When it returns EEDATA and EEDATH (both in bank 2) contain the (14 bit) data. It also autoincrements the address.

The model railway solenoids are called "points motors". The reason I suggested boden cables is because of noise. Boden cables allow you to mount the solenoids/motors in a sound proofed box. point motor page.

Mike.
Edit, there is no need to disable interrupts in the above code. I had to because I was writing to EEPROM in the ISR.
Also, here's a link to what I call boden cables. Refered to as pushrods.

 

Thanks for the info and the links, Pommie. The boden cables will no doubt be of use to my plans for future robots playing larger recorders (they come in all sizes right down to contra-bass, which is about as tall as a small person!). Truth is, I've been scratching my head the last couple days trying to make sense of the code. I won't bother you to explain it to me now (although it certainly wouldn't fall on deaf ears... ...blind eyes?... if you did), because I still have to get my head around the very basics of a PIC. Fortunately, some 16F88s arrived in the mail today, so I'll get cracking with some remedial programming attempts this weekend.

 

Here are a few more photos documenting my progress with RCD-1 this week. The first photo is probably the closest picture I'll get to the first concept drawing. Wooden braces to secure the recorder have been mounted on the 1/4-20 stock, themselves secured with nuts and washers.

Some scrap pieces of acrylic sheet are posing in to give an idea as to how the final project will look - yes, the sheet's a bit mucky, but it also has a glare-resistant coating on one side, in case you're wondering. Also sitting in for final-impression reasons only are four 1/2" square aluminum rods. Although not presently attached, these rods will eventually be bolted to the acrylic sheet with some brass machine screws, and the acrylic sheet will in turn be sandwiched between the wooden braces with two holes on each end of each sheet to accommodate the 1/4-20 stock.

In the second photo you can see a small piece of acrylic sheet on top with a solenoid bolted onto the sheet, again just as a trial to help visualize the final thing. From this (fuzzy - sorry about that!) perspective it looks like the solenoid pin is quite far from the recorder, but it's only between 1/4" and 1/2" away. This gap will of course be taken up by the padding and retraction mechanism mounted to the solenoid pin.

The last two photos give an idea of how the recorder fits into the wooden braces, with a custom-cut groove to match the unique contours of the instrument. I should have some photos of something close to the final physical parts of RCD-1 by the end of the weekend, and I'll be sure to post them here. Then, it's on to playing with the electronics end of things!

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Just thinking aloud.
Muscle wire? It's quiet.
http://www.elexp.com/kit_2mt3.htm

__________________
Bill
Smart Kits build Smart People
http://www.blueroomelectronics.com

 

But very slow?.

How this sort of thing has been done in the past usually used pneumatic actuators, fast and quiet - like anything else, it's been done many times before, over a number of decades.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

Depending on how general you want to be, attempts at automated musical instruments have been going on for, as far as I know at this point, about two centuries (automated trumpet player). If anyone has any documents, leads, personal accounts, etc. of that kind of thing, please let me know (PM or forum post as you see fit), no matter how trivial or incomplete your information may seem. Please use your discretion: instrument innovations such as the piano or pipe organ are not my main interest, but rather attempts to automate the practice of specific instruments, be they wind or otherwise. All are welcome, but the older the better.

My impression from what I could learn was that it was too slow, too expensive, and required too much more accommodation in mechanical design than something like solenoids, for example. As I've said before, there's obviously a coolness factor with something like muscle wire, but until it's more readily available, cheaper, faster, stronger, I'm going to opt for more traditional choices. Rest assured I'll be the first to hop on board as soon as it becomes practical to do so.

 

Very true!

But I was thinking of micro-processor powered ones, which I've seen examples of using air powered actuators - not sure if I've ever seen a recorder or not?, but certainly something along those lines (not trumpets, or instruments with valves).

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

I have hundreds of these printer hammers from some old IBM printers. The coils are 5.4 ohms, and will work off 2 AA batteries, but a little weak. Work fine off 6 volts, but in the service book the control line says 60 volts. They are huge printers...

Anyway, I've got a dozen or so that have been inside the house. The rest are still on two of the printers, and one block of them in the carport. The outside stuff, I have no idea of the condition, been atleast 10 years of huricanes and severe storms, intense heat, but should be okay. If interested, PM me and I'll put some in the mail for you.

Of, work fine directly off a 555, adding a transitor driver didn't seem to have any effect. Haven't tried anything with a microcontroller. They aren't very strong, so kind of killed the millipede robot idea I had...

That's a AAA size battery for scale...

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