Some help with gpio plugin and an original tuner controller

Help and Support
1

Hello,

I’m currently upgrading an old QUAD FM4 tuner into a dac streamer, i have everything stripped out of the box and have successfully install an oled screen that looks awesome, via a RPI3 and an IQuadio dac+

The next step is to connect the original tuner buttons and leds. I have ordered a MCP23017 expansion board to connect it to the pi and I’m hopefully going to use the GPIO plugin.

fm-4_2q
fm-4_2q2050×1397 226 KB

This is the button controls I want to connect.

fm-4_2t
fm-4_2t2050×1338 260 KB

And the back

Has anyone done something similar and can give me some pointers, links or guidance. I would ideally like to get the leds working too. I have figured out what the cables do with the help from a mate who very kindly worked out whats what.

333298881_6025832257465292_1138999777335055780_n
333298881_6025832257465292_1138999777335055780_n1920×888 247 KB

Stripped down ribbon cable

335246384_1566223603886760_5803813546913567169_n
335246384_1566223603886760_5803813546913567169_n2048×1344 205 KB

Many thanks
Matt

2 Likes
2

The GPIO plugin will not work as you need to program 16 GPIO pins.
GPIO 2,3,18,19,20,20 can’t be used as the are being used the DAC+.

you need to set 8GPIO as in and 8 as out.

3

Thanks for your reply, I might just use the first 4 buttons/leds to begin with until I get my head around it. Will the MCP23017 expansion board not solve this problem?

4

Well you need to add pull-up or pull-down resistors .
How to get the MCP23017 working with pi, no clue. Never done it. I am a lazy baster and bought this;

5

I’m not entirely sure what that is? would it help with what i’m trying to do?

6

Seems your mean something else?

image
image825×282 35.8 KB

7

one of these:

CQRobot Ocean: MCP23017 IO Expansion Board Compatible with Raspberry Pi/micro:bit/Arduino/STM32 Motherboard. I2C Interface, Expands 16 I/O Pins, Up to 8 Expansion Boards Can be Used Simultaneously. : Amazon.co.uk: Business, Industry & Science

8

can’t confirm, seems to run on GPIO 2,3 which are already used by the DAC.
And don’t know if the drivers are included in the Volumio image. Guess you need to do some testing.

9

Damn. So I cant use those pins?

10

most likely not with that DAC. You need to test it. Hifiberry also uses GPIO2-3 but it has no problem with the OLED I have attached to the same GPIO.

11

I just read the I2C is a master and slave so as long as the other has a different address it will work… but maybe not as a hat?

Thanks for the advice/info

12

i2c-shared
i2c-shared1161×811 122 KB

Apparently according to Iqaudio the I2c can be shared across multiple boards, so fingers and toes crossed.

13

and ears crossed too :slight_smile:

1 Like
14

Good project Matt :+1:
(I’ve got a (39 year old) Quad FM4, but it’s staying as a tuner).

I’ve got a Digi HAT board using some of the GPIO pins, but only needed enough for 3 transport functions and a shutdown.
So I could use the ‘GPIO Buttons’ plugin to do this:

It depends what / how many functions you want to allocate to your remaining GPIO pins, as to whether you’ll be able to do all that you want with your FM4 buttons / LEDs.

Good luck - you can pretty much guarantee your finished product will be unique in the world.