15 button input follow with output to LED

Using Arduino LEDs and Multiplexing
1

I would like to know if it’s possible to use a Pico board to control a set of 15 inputs that output 15 outputs as each is received,.

The 15 output channels would drive a LED with momentary button press and turns off all the other LED outputs off except for the one pressed. So button 1 pressed, LED 1 on. Button 3 pressed, LED 3 comes on etc, thank you. Is this possible please,

So it’s a button follow type feature for a Wurlitzer organ I have, the keyboards have 15 buttons each below the keys, these are called pistons. These pistons illuminate when pressed, I would like the last piston pressed to stay on and any previous ON buttons off?

Thank you,

Colin

2

Yes this should be possible.

However 30 inputs / outputs is more than the Pico has, so you will need some sort of port expansion chip, like a shift register to multiplex your signals.

3

Hi Mike,

Thank you for your reply. I see that in one of the videos. And I guess a scan type IC for the inputs too?

Hopefully someone can guide me with this please?

4

Sure, go ahead. We will tell you if you guessed correctly.

5

Also it is possible to do this using Pico without any additional chips/modules, by organising your buttons and LEDs as a matrix.

For example a 5x3 matrix would need only 3 pins for the LEDs, 3 pins for the buttons and 5 pins to scan the rows/columns of the matrix.

Question: would only 1 button ever be pressed at any instant in time? Or could another button be pressed at a time when a previous button had not yet been released?

6

By the way, this seems like a terrible waste of a very capable board. You would be using 0.00...01% of it's capabilities with this task!

Even a Nano 3 or Pro Mini would not be taxed by this project, you could choose something like that.

7

Thank you Paul,

It’s for the pistons below the keyboards, ideally only one per keyboard would be pressed,

IMG_1179
IMG_11791600×2134 769 KB

8

I see these keyboards only have 10, not 15 as you described.

How many keyboards in your project? Were you planning to use a Pico per keyboard?

9

Hi Paul,

I plan to add extra buttons to the left and use one ardunino per keyboard

Regards

Colin

10

So, 45 LEDs and 45 buttons in total?

With a 5x9 matrix, you would need 5 pins for LEDs, 5 pins for buttons and 9 pins for row/column scanning. 19 pins in total. I think a single Pico has enough for that, depending on how many pins are required for other functions.

11

Posting attachment on behalf of @niceonetidy ..

Conn 652 Virtual Theatre Organ.pdf (1.5 MB)

12

What made you think I was restoring an organ? I don't have the skills or equipment for it...

13
14

There are many ways to increase the number of inputs/outputs available on a controller.

Using matrices can avoid the need to add additional chips, as I mentioned before.

There are also i/o expander chips that use i2c or SPI bus, like pcf8574, pcf8575, mcp23008, mcp230S17 and more.

Can you tell us more about the electronic parts of the organ? Is there a PC/laptop behind the scenes? How is it interfaced with the organ at the moment?

15

Yes, but there are expert coders on the forum, and experts on Arduino, Raspberry Pi etc. for example @Grumpy_Mike. The forum won't do all the hard work for you, but as long as you are willing to learn you will get unlimited help.