Midi Decoder

Rut

I am going to rebuild a Tangley Calliope. I would like it to play from a SD card. I can build the unit, but I am not a designer. Does anyone have information on this subject? It has 43 notes and I will be using low voltage solenoids to operate the keys. It wold be nice to use a newer propeller chip.

Rut

Mike Green

What is the voltage rating of the solenoids and (more important) what is the current rating? How many keys can be activated at a time?

You will need some kind of "high voltage high current" driver, probably just a power transistor, but you'll also need some way to control 43 solenoids using maybe 12 I/O pins ... easy enough to do.

James Long

Rut said...
I am going to rebuild a Tangley Calliope. I would like it to play from a SD card. I can build the unit, but I am not a designer. Does anyone have information on this subject? It has 43 notes and I will be using low voltage solenoids to operate the keys. It wold be nice to use a newer propeller chip.

Rut

Rut,

I'm working on something right now just for what you are wanting.

If your interested, let me know.

James L

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James L
Partner/Designer

Lil Brother SMT Assembly Services

Bob Lawrence (VE1RLL)

To get started in Propeller MIDI you Use the link below to read about the project that Thomas Dimock dsigned - Computerized Pyrotechnic Firing System . He also worked on a pipe organ project that may offer you some tips.

"Enter the Propeller! I initially started working with the Propeller chip building a controller for my pipe organ, and designed a MidiIn object as part of that project (subsequently contributed to the object exchange) that could receive a MIDI stream and use I to control the electro-pneumatic valves in the pipe organ. It occurred to me that if I replaced the switches in my existing firing system with relays, that I could use MIDI to create choreographed shows."

www.parallax.com/tabid/716/Default.aspx


Pictures for those that have no idea what a "Tangley Calliope" is:

www.antiquemechanicalrestorations.com/Tangley_Calliope.html

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Aka: CosmicBob

Bob Lawrence (VE1RLL)

TANGLEY CALLIOPE RESTORATION PROJECT (The Entire Series)

www.carousels.com/bblack/calliope.php

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Aka: CosmicBob

JonnyMac

I'm presently looking into the TI TPIC6A595 chip; it's like a '595 shift-register with moderate current (350mA each, up to 50v) outputs. I believe there is already a '595 object; this chip may assist in expanding the outputs you need to drive a lot of valves/relays.

James Long

JonnyMac said...
I'm presently looking into the TI TPIC6A595 chip; it's like a '595 shift-register with moderate current (350mA each, up to 50v) outputs. I believe there is already a '595 object; this chip may assist in expanding the outputs you need to drive a lot of valves/relays.

I'm currently using the PCF8575 I2C chip. It works well, but does create one problem. The outputs are on when the chip is powered up. I'm getting around that by putting a mosfet on the darlington output power line. The mosfet is turned on after the Propeller boots.

The PCF8575 will allow up to 128 outputs using two I/O. Currently I'm driving the chips at 400K, so we are about 2x faster than the music streams from the SD card.

James L

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James L
Partner/Designer

Lil Brother SMT Assembly Services

Adam Wiesler

Rut, I did something like this last year, only with bells.
I made a custom board to control it and i have the designs posted on my website.
www.quigleyelectronics.com-a.googlepages.com/home
just tell me if you want the .pcb files for expresspcb.com
you can probably modify it for some other chip and SD.
Have fun, Adam