pocket piano..

Projects General Guidance
1

hello
i have just two questions about the pocket piano
im having just a little bit of trouble with the schematic
i don't know where to connect the two capacitors located near the multiplexer chips (vcc and grd)
(are they connected to pins on the capacitors or to the arduino)
there is also one located near the mcp 4921 chip

and secondly
where the sting of three potentiometers there is a vcc out and a pot 1
(i am wondering if that pot 1 is a typo and is suppose to be a GRD)

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Please help!!!
thanks in advance for your time
chris

2

Hi,
The 3 capacitors from Vcc-Gnd should go as close as reasonably possible to the Vcc and Ground pins on the chips.

And it does look like that POT_1 connection on right of pots should go to ground, assuming that those pot outputs are going into analog inputs??

3

so the capasitor goes between the 3 specific ic from vcc to grd ?!?
i think thats what you mean
and iam wondering if the vcc and grd ar going all to the adruino and not strat to the battery? :~
sorry im a newb

4

Wouldn't it be better to ask the guy who designed it?

Pete

5

No one answered because they are trying to sell it built without the arduino now. Anyone have any ideas or figure it out?

6

The three caps between the multiplexers and DAC are decoupling caps.
Seems they have used 0.1uF (100n), but used the wrong symbol of an electrolytic cap.
A 100n ceramic cap per chip (close to each chip) is recommended for digital ICs.

POT_1 to the right can't be anything else than ground.
Leo..

7

Hi,
"Pocket Piano" links please..

Tom.... :slight_smile:

8

1024×697 76.1 KB

423×631 30.7 KB

9

Hi,
Is this it;

Also if you look at your PCB and trace the tracks you will find the answer to you questions.

Vcc and gnd will be going to the arduino through the shield, as the pot Vcc needs to be regulated.

Tom... :slight_smile:

10

Awesomeness
Thats so much TomGeorge
Been working on and off this project trying to figure it out... building it from scratch because its hard to find the kits anymore
Found out I was working with a fried arduino recently as it won't even run the blink sketch properly
Gotta get another arduino and test it out!!!
Thanks again !

11

Hi! did you managed to get it to work? does the arduino version handle multiple presets?