My version of Volumio streamer with Waveshare 7.9" touchscreen

Diy and Tweaks Diy Volumio Projects
21

Congratulations about this project.

Is it possible to share withs us this next points?

  • Power Supply Circuit diagram (is there a board ready to buy?)
  • USB Board Circuit or if there is as board ready to buy.
  • DAC Board used
  • RCA conector board used
  • How this case is constructed?

Thanks in advance.

22

Thanks. The boards have irregular shapes as they are built around Pi 4 and the case. I’m not sure if they are really helpful if put into another case. But I am happy to share more details and schematic:

  • Power Supply Circuit diagram (is there a board ready to buy?)

see below photo

  • USB Board Circuit or if there is as board ready to buy.

see below photo

  • DAC Board used

Allo Boss 2 DAC

  • RCA conector board used

it’s just a very simple connector

  • How this case is constructed?

fabricated in two aluminum factories - one for CNC and another for laser cut

LPS:

LPS
LPS1842×938 68.9 KB

USB galvanic isolation for touchscreen:

USB
USB1248×864 89.1 KB

1 Like
23

Thanks a lot Vincent

As I plan to start my Project from zero, I can decide to implement it in case as needed.

In this case, I’ll apreciate if its possible to buy that board from USB Galvanic Isolation for Touchscreen. Is it possible?

24

It’s possible but are you OK with the shipping fee? The cost is around 25USD but the shipping fee to Brazil is around 15USD.
Additionally you need a separate 7Vac/1A power for the touchscreen.

25

I think your kit looks fantastic. I am using Volumio and the PI4 without a DAC. I am USB connected to a SMSL M300 MkII DAC. I see your USB jumper on the back of the unit. What is that jumper doing? Would it interfere with streaming out the USB to my external DAC?

Thanks and GREAT job!

1 Like
26

Thanks. The touchscreen interface is USB, which needs to be connected to one of the USB ports on Pi 4. The USB jumper bridges the signal of the touchscreen to Pi 4. Surely it will not interfere with streaming, you can imagine it as an USB extender/extension cable.

1 Like
27

Thank you for your reply. I have another question. Please do not think I am disrespecting your work. It is FANTASTIC! I really like what you have built.

My question is; The display appears to be capable of being driven off of USB or HDMI. I was not sure if you have an operating system restriction with DietPi that had you use USB rather than HDMI, (I’ve never used DietPi).

I will only be using Volumio and I know it works flawless with HDMI. Is there any reason you know of that would stop me from buying your kit and using HDMI for the display

I see in the display information it can be powered with 5V/2A power through the Power interface on the back of the LCD. Is there a tap available on your LPS to power the display this way, or only through USB?

I ask because I only use my external SMSL DAC. I am currently using a PI4 with an official PI 7" touch display connected and the system sounds really good, but yours looks more professional with a top notch case and display. However, I would prefer no USB bridges in place since I don’t use a DAC hat.

Thanks again for your help. :slight_smile:

28

No problem.
I think you misunderstood how the touchscreen works. You only need to connect 1 flat cable to the official 7" touchscreen to make both the “display” and “touch” work becos of the low resolution (800x480) and low color bit depth. “Touch” signal is also passed from the official touchscreen to Pi becos of the “not so high” bandwidth requirement.
However with the use of HDMI touchscreen, “display” and “touch” signals are separated. HDMI, by definition, is an interface of high resolution display. While the USB cable (and the USB jumper) you see from the photos, conveys the “touch” signals (in terms of x,y coordinates) from the touchscreen to Pi, so that Pi knows what locations the user is touching, and responses to the input accordingly.
As mentioned earlier, the USB jumper bridges the “touch” signal from the touchscreen to Pi, it is required anyway, otherwise the “touch” won’t work. And it work not interfere with your external DAC becos the signal path is not shared.
The touchscreen can be powered by the “touch” port alone, the power inlet provides an auxiliary power source in case the USB port of Pi 4 cannot deliver enough power. Anyway, the touchscreen has its own power source and it’s galvanically isolated from Pi 4 as to prevent electrical noises from entering the audio path.
I hope you can understand what I mean.

29

I do understand. Thank you for the detailed reply.

30

Nice peace :ok_hand:

Thats funny i tried to build a columio with the same display but did not get it confugured :confused:

Do you have a ready image for the Pi? Would like to download and install this :slight_smile:

And if possible a CAD plan for the case to make it myself (a friend has a CNC machine) would be great :muscle::hugs::smirk: