MIDI converter for use with the Yamaha BC3A Breath Controller

[stryd_one]

Nice one man! :)

I think the 7912 might do the -12v?

[gabz]

YEs I think I will use a regulator like this

tomorrow or the next week will say this  ;)

thanks again

[DrBunsen]

I've used a BC before, and I am pretty sure that your friend is wrong about it being temperature.  Think how instant the response is from the BC and how closely it tracks the pressure of your breath.  If it was temperature, there would be a delay as the resistor cools down, between when you first blow and the response from the synth.  You couldn't get those fast honking attacks you get when you blow hard.  There would also be another delay when you -stop- blowing as the resistor heats up again.

From memory, I think it's a -force- sensing resistor (FSR) - it changes resistance as it bends.  Think of the slight back pressure you feel as you start to blow, and how you have to blow quite hard at first to get past that pressure.  I've also seen a homebrew clone around somewhere, and I think that used an FSR as well.  

[gabz]

Yes this is a FSR (As whitfield said to me) I forgot to tell about

Obviously, yes it's really reactive to pressure, not to temperature ...

I found my solution to power the system : I found an old ATX alimentation ... that provides -12 + 12 - 5 + 5 I will power the whole midi box with it ...

I don't even need to make a schematic since it is the most basic thing :

An inverting amplifier, You just have to solder it like this, And Take R1 = 2 R2 , So you get max 5V instead of max 10V

I didnt tried it but It should work ...

[stryd_one]

I found my solution to power the system : I found an old ATX alimentation ... that provides -12 + 12 - 5 + 5 I will power the whole midi box with it ...

I'm sure I read somewhere that that won't work because it's switching.... Could be wrong? If I am wrong then I have access to hundreds of power supplies, who wants one?  ;)

[goyousalukis]

Here's a site that shows you how to convert a switching power supply:

http://web2.murraystate.edu/andy.batts/ps/PowerSupply.htm

Justin

[gabz]

thanks for the informations ! I didn't know that I couldn't work ...

Are all the ATX switching ? I will try what's showed on this page ... hope it will work

[gabz]

So, I made the mountage with the ATX, and it work even without a Charge

Maybe because it's an OLD ATX power supply ?

So ... all work perfectly