LCD / LCD Backpack wiring

[stevemesser]

I am trying to make your project. I found a FM tuner exactly like yours.

1. Do you happen to have more detailed wiring information about
   a. LCD and Back pack
   b. How you wired up the tuning knob
   c. the breakout board
2. How did you power the existing front panel?

I am handy with electronics but not as handy as you. Any extra guidance you could provide would be appreciated.

[alanb128]

LCD and Back pack

Here's the guide I used for the LCD and backpack: https://learn.adafruit.com/i2c-spi-lcd-backpack

How you wired up the tuning knob

On my Sony tuners, the tuning knob was included in the row and column matrix, so no additional wiring was required - check the schematic for your exact tuner model. (Even models that look the same can have different model numbers)

the breakout board

The breakout board was just a way to connect the ribbon cable leads I soldered onto the tuning board to the male GPIO pins on the Pi. It can be done many ways. I used a board like this: https://www.adafruit.com/product/1608 along with a strip of male headers and female-to-female jumpers.

How did you power the existing front panel

It is actually passive when just using the front panel switches, so no power is needed!

Good luck and keep us posted!

[stevemesser]

Sony FM control panel button matrix

1. I have removed the current display
2. I have desoldered the chip that was under the display
3. Looking at the schematic I see the matrix you have mentioned in your video.
   What I see is it appears to me that
   Pins 15, 16, 24, 25 seem to be the vertical lines of the matrix
   Pins 30, 31, 33, 34, 35 seem to be the hortizontal lines of the matrix
   Not sure about pins 32 and 33.

I thought that if I connected my multimeter in continuity mode to pins 16 and 30 then pressing the Band button would get a beep. However, it did not.

What I am missing?

[alanb128]

My schematic is for the "ST_JX412/JX521" so that's what I'm going by. Your numbering sounds correct, but pins 28, 29, and 33 are also rows. Pin 32 is ground - make sure you do not connect the board ground to ground on the Pi or it won't work. I did not try continuity testing on my board so I don't know if you should get a beep or not - I'm not sure how the diodes would affect that.

Also make sure you update the rows and columns in the code to correspond to the GPIO pins you use.

[stevemesser]

One more question and I hope I will be good to go.

In your video you mention only needing 11 instead of 17 wires because of the matrix.
In your flask-api.py code you only reference 9 GPIO pins.

Which of the 11 wires from the control board are you actually using?

[alanb128]

The "11 wires instead of 17" is just purely going off the schematic. In my build the four "key input" pins are the columns and the five active "key output" pins are the rows. (Two key output pins don't connect to any switches.)

[stevemesser]

I have the same device and schematic as you do.
So I am trying to figure out which two wires I don't need

Pin 15 Key Input
Pin 16 Key Input
Pin 24 Key Input
Pin 25 Key Input

Pin 28 Key Output
Pin 29 Key Output
Pin 30 Key Output
Pin 31 Key Output
Pin 33 Key Output
Pin 34 Key Output
Pin 35 Key Output

My guess would be I don't need Pins 28 and 29.

Could you please verify that for me?

[alanb128]

Correct, I don't think you need pin 28 and 29.