Adding an External Volume Control

#10

In the config.txt, any line with a # in front of it is ignored. Its treated as just a comment if you will.
Delete the # from the front of the line and that line is executed.
So as an example

Uncomment some or all of these to enable the optional hardware interfaces

dtparam=i2c_arm=on (does something)
#dtparam=i2s=on ( is ignored)
#dtparam=spi=on ( is ignored)

You can’t use your analog volume control with the X-Hat. Not and use the X-Hat amplifier and speaker. The signal going from the Pi to the X-Hat DAC is a digital signal, 1’s and 0’s. i2s
What I did was take the analog stereo output that comes out of the Pi’s audio jack and feed it to my dual POT. The signal out of the Pi’s audio jack is a low level analog signal. It will drive earbuds but thats about all. It has to be amplified to drive speakers.
My volume control is two POTs connected to the one shaft. Stereo if you will. I took a stereo cord with a tip ring sleeve jack on one end and wired the other end to my POTs. The adjustable side goes to my stereo amplifier. The center wiper contact of the POT. The amplifier then feeds my speakers, which are not shown.
To do what I did you’d need to switch to a separate analog amplifier. And ditch using the DAC on the X-Hat.
My full build pictures for that Pi are here, https://1drv.ms/f/s!AjOYwiwlwDtpgq9LUHdGiiRpn7dr2Q

DSCF0826
DSCF0826.JPG4608×3456 3.63 MB

#11

Thanks again

I followed the link:

Which is near the start of the config.txt file, but you made it so much clearer, so all I need do to get retropie to ignore a command is delete the # at the start of the line, brilliant I get that now.

So would I remove (uncomment) the # at the start of this code?:

Enable audio (loads snd_bcm2835)

dtparam=audio=on
gpu_mem_256=128
gpu_mem_512=256
gpu_mem_1024=256
overscan_scale=1
hdmi_force_hotplug=1
dtoverlay=picade
dtparam=audio=off

In order to output the audio back through the Rpi’s audio jack?.

Or is it this line:

uncomment to force a HDMI mode rather than DVI. This can make audio work in

DMT (computer monitor) modes

#hdmi_drive=2

Also would I be better off ditching the supplied X_Hat and using something else?, I see from your pictures which are pretty impressive! that you’re using a gamepad, I like the arcade controls but I know the X_Hat is a new development and that other controller boards are available, and could I be cheeky and ask if any are recommended.

#12

It’s the other way around, add a # at the start to comment it out and have a line ignored, and “remove the #” (uncomment) a line to have it acted on.
dtparam=audio=on is I believe the one that turns on the built in sound chip, the bcm2835.
You don’t want an on and an off, the off at the end will turn it off.

#13

Hi no my friend once it is configured you dont have to go to the retroarch option. In a game you can change the volume without exit

#14

I think we dont understand each other. You dont have to do all this. Send me your mail, Im gonna send you a video of how I do without it. Dont do all these complicated stuff

#15

Well thank you both alphanumeric & VaFank for taking the time to bother to reply I’m quite amazed by this to be honest.

Alphanumeric I’m not going to have time this evening to play with the config.txt file will look at it tomorrow afternoon when I get some “me time” that doesn’t involve bikes or family, I understand the uncommenting now thanks to your reply and me actually looking at the Rpi forums, no bios huh!

VaFank I honestly don’t know how I send you my e-mail address, but will look into that tomorrow as well.

Again a big thank you to you both.

#16

Yeah, it took me a little while to wrap my head around the no BIOS. The confix.txt is sort of kind of the Pi’s equivalent. It reads that first to turn things on off etc. The nice thing about no BIOS is you can’t brick your Pi by messing with the config.txt. Worst case scenario is it just doesn’t boot. Redo your Micro SD card and your back in business.

If you click on VaFank’s avatar you should get a message option. Click that and you can send him a private message only he can see.

#17

Thanks for the “clicking on the avatar” heads up.

#18

No problem glad to help.
Where it is depends on the forum software being used, if its enabled. Some forums have it turned off.
Some times its in plain site some times you have to go look for it.

#19

HI all

Ok VaFank I’ve done what you described in the post above to set up the joystick as a volume control in the " input hotkey binds" sub menu of retroarch and absolutely no luck, I’m obviously going wrong somewhere, but I’ve no idea where!.

FYI I updated everything I could find to the newest version then I had a fun ten minutes trying to work out how to log back in, all sorted now, except for the sound obviously, I still think adding an external volume control is easier than what I’ve been doing for the last five hours of Picade use, perhaps there’s some instructions somewhere, but if there are they’re well hidden.

#20

I have a bit of an update now…

I do still want an external volume control, but at this point I’d be willing to be able to control volume without having to exit out of a game and go into the “ncurses” style volume menu!, I honestly can’t find any other way to control the volume and I’ve re-installed retropie twice and set it up as suggested in the build video.

I’ve tried mapping the joystick & the “select” button to control sound together but retroarch doesn’t allow me to do this and I’ve no idea why, also it only gives me 4 seconds to do it and as soon as I push up and the select button it times out, I think most of the problem is xhat related and specifically it’s stupid sound setup it seems very restricted especially the way it disables the Pi’s on board stereo jack and then doesn’t give an option to re-enable it I realise this isn’t a retropie/retroarch issue but to do with the software you download from pimoroni when you first install the system, I am super tempted to dump it and fit the “zero delay arcade usb encoder” as listed on other sites as I’ve no idea how to get the sound sent through the jack again.

If anyone has any thoughts could you suggest a fix, but at this point dropping £9.00 on the encoder seems like a fair trade to get my sanity back.

#21

One way to go about it is to install just Raspbian. Set your sound to the onboard audio jack, confirm it works, then copy that config.txt to a safe place like a thumb drive.
Then install the X-Hat software and compare the two config.txt files to see what was changed.
Then edit the current one to get the stock audio back.
Or rename the current config.txt to config.bak and copy in the one you saved.
Then see if it breaks the X-Hat.

The encoder is likely going to be very hard to setup for volume. IMHO anyway.
Do you have a plan for that already in the works?

#22

Hi alphanumeric

I did try installing base Raspbian and thought I’d be able to get something like retroarch up & running but I couldn’t.

I looked at the encoder because it seems to be plug & play, it comes with the wiring for the buttons & joystick and from what I can see you just plug it into the Pi via usb, then setup the button & joystick mapping in retropie and off you go, it leaves the Pi’s audio alone so all I need do then would be to plug in a mono ring tip jack with a log pot for volume and wire it straight to the speaker.

I know I’m going to have to put a power switch on as well I was looking at the on/off shim but considering the trouble I’m having with the xhat set up so far it’s put me off pimoroni stuff.

Or is this wishful thinking.

Obviously I’d prefer to get sound control through the Picade xhat working and then maybe work out how to put external volume control on there, but this is where I am.

Also if anyone’s reading this and is put off from getting a Picade please don’t be they’re great, it’s just that I’m having sound control issues.

#23

Ok, when you said encoder I was thinking this, https://shop.pimoroni.com/products/rotary-encoder-illuminated-rgb
Can you please post a link to the “encoder” you want to use?

#24

it’s on a different Pi site, is this allowed?

#25

I think so? I’ve linked to Adafruit stuff, but they also sell Pimoroni stuff. I think I know what it is now anyway, after a Google search. From the product description it “should” work. I’m having a hard time buying into the Zero delay bit though.

#26

Hello again alphanumeric

yep the “Zero delay” is the bit that stopped me in my tracks (from buying it immediately), I can’t see how it converts the button & Joystick output through to usb without some kind of slowdown, but yeah in case were looking at different things:

https://www.modmypi.com/raspberry-pi/arcade/arcade-controllers/zero-delay-arcade-usb-encoder-and-wire-set

So do we still think “zero delay” isn’t and that there may be a bit of lag?, but the features description does make a bit of a thing about the lack of lag

Anyway thanks for taking the time for a reply, also I had a thought that maybe there really is something wrong with the xhat and that maybe I should contact Pimoroni to ask for some sort of sound control setup instructions, because there doesn’t appear to be any.

#27

Yeah, thats what a google search led me too. I haven’t looked all that close at it but if it emulates a HID (keyboard mouse) device maybe there isn’t all that much lag? I play FPS games on my PC with a keyboard mouse all the time. Now that I give it more thought I guess its no worse than plugging in a joystick and or USB game controller?
I don’t currently own an X-Hat or Picade. I may buy one at some point, not sure when that might be though? So basically I can’t help you with that part of your problem, the setting the volume issue.

If you go to the Shop page, there is a “contact us” link at the bottom. You can use that to contact Pimoroni directly, just put a link to this thread in the support e-mail.

#28

Thanks again
I’m going to do that, it’s my last day 'till Monday so I should have some time, and I will link back to this thread, will update here if I get anywhere.

#29

Hi All

Had a reply from Matt at Pimoroni with a link to the retropie forums:

but it seems the posters there want to do what I want to do! ie at this point just control the sound without shutting down a game!, but as I’ve found there’s no real solution to be had.

If someone reading this has followed the link and understands what to do could you give me a hint.

I spent most of my free time over the weekend trying to get some kind of button mapping to control the sound but I get no where.
I’ve tried installing retropie without adding the pimoroni software for the Picade Xhat but obviously I had serious button & joystick mapping issues, I did get them to work (sort of), so I’m back where I was there doesn’t seem to be a great deal of support for the Picade from Pimoroni for this issue.

My next plan is to buy the zero lag arcade controller (in my link in a previous post) and get an on off button for the Pi ,wire in a mono ring tip jack plug to the Pi’s audio out jack and a log pot to the speaker and see what happens then, as in this link I found:

http://www.learningaboutelectronics.com/Articles/How-to-build-a-speaker-circuit-with-adjustable-volume

it shouldn’t cost too much to do either as I have most of the bits.

I’d like to ask if anyone reads this and knows how, how do I alter my Original Post title from " Adding an External Volume Control" to something more descriptive as I now realise I’d be really happy to settle for easier sound control on the Picade, and people on the forums may not be looking at my post because adding an external volume control isn’t for them.

Thanks for reading.