Savage1ZA
Posts: 10
Joined: Fri Jan 10, 2020 3:03 pm

Looking for 5" LCD goodness

Fri Jan 10, 2020 3:21 pm

Hi All,

I'm looking for recommendations for a 5" please,

- LCD module with controller PCB to be as thin as possible (this rules out HDMI/USB connectors on the LCD/PCB panel itself)
- SPI, HDMI, or Display port connections via (preferably) ribbon connection - i.e. thin
- Power same story as above (no HDMI/USB connectors)
- PWM back light control
- 800x480 is sufficient

Something like the Waveshare 5" would be ideal (and size can't be much bigger than the Waveshare), but the connectors on the Waveshare won't work in my application/design. Not requiring drivers will also be an advantage. I'm not after massively high refresh rates, touch screen functionality or anything fancy here.

To be used with a Compute3

Ta - looking forward to some recommendations

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mooblie
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Location: The Scottish Highlands

Re: Looking for 5" goodness

Fri Jan 10, 2020 4:20 pm

I have one of these, and it works well:

https://www.amazon.co.uk/dp/B07ZD4QGQJ

...but it has a standard HDMI socket, hence the PCB module alone is 14mm thick. A shame if it is really too thick for your application?

trejan
Posts: 1094
Joined: Tue Jul 02, 2019 2:28 pm

Re: Looking for 5" goodness

Fri Jan 10, 2020 4:32 pm

DFRobot have a 5" clone of the Pi LCD that connects via DSI. Same 800x480 resolution but touchscreen is only 5 point. No PWM backlight though which might be a dealbreaker for you.

Savage1ZA
Posts: 10
Joined: Fri Jan 10, 2020 3:03 pm

Re: Looking for 5" goodness

Fri Jan 10, 2020 5:27 pm

mooblie wrote:
Fri Jan 10, 2020 4:20 pm
I have one of these, and it works well:

https://www.amazon.co.uk/dp/B07ZD4QGQJ

...but it has a standard HDMI socket, hence the PCB module alone is 14mm thick. A shame if it is really too thick for your application?
Yeah - unfortunately it needs to mount on top of an existing PCB with a lot of tactile buttons (+-70 of them, all back lit). If the LCD's to far from the PCB the push buttons and back lighting will be an issue.

There's soo many (and it's so common) ribbon + HDMI/MicroHDMI connector kits out there, I'm actually surprised that no LCD manufacturer (from what I can see) has released something more compact.

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Imperf3kt
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Location: Australia

Re: Looking for 5" goodness

Fri Jan 10, 2020 7:51 pm

I've recently been looking at this 4.3" Waveshare Pi monitor for similar reasons as you.
https://www.waveshare.com/product/oleds ... si-lcd.htm

Maybe it will work?
55:55:44:44:4C
52:4C:52:42:41

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HawaiianPi
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Location: Aloha, Oregon USA

Re: Looking for 5" goodness

Fri Jan 10, 2020 8:03 pm

This may be the same one trejan recommended above. It's the only other DSI screen I've seen, and it seems pretty thin in the pictures.

Picture is link.
Image
My mind is like a browser. 27 tabs are open, 9 aren't responding,
lots of pop-ups...and where is that annoying music coming from?

Savage1ZA
Posts: 10
Joined: Fri Jan 10, 2020 3:03 pm

Re: Looking for 5" goodness

Fri Jan 10, 2020 10:07 pm

HawaiianPi wrote:
Fri Jan 10, 2020 8:03 pm
This may be the same one trejan recommended above. It's the only other DSI screen I've seen, and it seems pretty thin in the pictures.
Not the same as the Waveshare (which also has a 5", but it is DPI with a RGB HAT and uses all of the GPIOs).

Thanks for this - this one is definitely interesting, and a contender. The fact that it's DSI is a huge plus I think.

trejan
Posts: 1094
Joined: Tue Jul 02, 2019 2:28 pm

Re: Looking for 5" goodness

Fri Jan 10, 2020 10:33 pm

Savage1ZA wrote:
Fri Jan 10, 2020 10:07 pm
Not the same as the Waveshare (which also has a 5", but it is DPI with a RGB HAT and uses all of the GPIOs).
The DFRobot 5" touchscreen is DSI not DPI so nothing like the Waveshare display. It seems to be nearly identical to the OSOYOO design except the DFRobot one has a potentiometer for the backlight brightness for some strange reason. The OSOYOO wiki says you can control the backlight on their one via /sys/class/backlight/rpi_backlight/brightness so that one is a better option.

Note that the supplied ribbon cable on both of these displays is very short and not the same as the normal Pi camera/display ribbon cable. If you use the normal Pi camera/display ribbon cables then you'll be wiring the display backwards and risking damage to the Pi + display.

Savage1ZA
Posts: 10
Joined: Fri Jan 10, 2020 3:03 pm

Re: Looking for 5" goodness

Fri Jan 10, 2020 10:48 pm

trejan wrote:
Fri Jan 10, 2020 10:33 pm
The DFRobot 5" touchscreen is DSI not DPI so nothing like the Waveshare display. It seems to be nearly identical to the OSOYOO design except the DFRobot one has a potentiometer for the backlight brightness for some strange reason. The OSOYOO wiki says you can control the backlight on their one via /sys/class/backlight/rpi_backlight/brightness so that one is a better option.

Note that the supplied ribbon cable on both of these displays is very short and not the same as the normal Pi camera/display ribbon cable. If you use the normal Pi camera/display ribbon cables then you'll be wiring the display backwards and risking damage to the Pi + display.
Sorry, I was referring to the other post about the 4.3" Waveshare.

This one does indeed look almost identical to the OSOYOO (just purchased, arriving next week Wed. for testing). The dfrobot's not only a slight bit cheaper, but as you said - a bit more feature rich as well. It's fairly thin as well based on what I am seeing from pictures

I'll use the OSOYOO for my prototyping for now (assuming it will work), and will most certainly get a dfrobot too - both are cheap enough. Sorry I missed this post by accident :D

If there's any others to look at / suggestions, let's keep them coming. I don't think these kind of screens are as well known as they should be.

trejan
Posts: 1094
Joined: Tue Jul 02, 2019 2:28 pm

Re: Looking for 5" goodness

Fri Jan 10, 2020 11:26 pm

Savage1ZA wrote:
Fri Jan 10, 2020 10:48 pm
This one does indeed look almost identical to the OSOYOO (just purchased, arriving next week Wed. for testing). The dfrobot's not only a slight bit cheaper, but as you said - a bit more feature rich as well. It's fairly thin as well based on what I am seeing from pictures

I'll use the OSOYOO for my prototyping for now (assuming it will work), and will most certainly get a dfrobot too - both are cheap enough. Sorry I missed this post by accident :D
You misunderstand. The DFRobot one is worse than the OSOYOO one. The adjustment dial is the only way to change the backlight brightness on the DFRobot version. The comments on the DFRobot product page has people asking for source for the STM32 uC on the back to implement software backlight control but the DFRobot staff refuse to release source and say to use the adjustment dial.

Savage1ZA
Posts: 10
Joined: Fri Jan 10, 2020 3:03 pm

Re: Looking for 5" goodness

Sat Jan 11, 2020 11:15 am

Hi Guys (again),

Sorry for being a pain, but I'm looking at the CM3's dev schematics now (https://www.raspberrypi.org/documentati ... IO_3p0.pdf), trying to wire in DISP0 into my circuit.

For the love of me, where does CD0_SCL & CD0_SDA come from?

trejan
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Joined: Tue Jul 02, 2019 2:28 pm

Re: Looking for 5" goodness

Sat Jan 11, 2020 1:26 pm

Savage1ZA wrote:
Sat Jan 11, 2020 11:15 am
For the love of me, where does CD0_SCL & CD0_SDA come from?
They're connected to J6. You're supposed to add a jumper from CD0_SCL/CD0_SDA to the GPIOs.

Savage1ZA
Posts: 10
Joined: Fri Jan 10, 2020 3:03 pm

Re: Looking for 5" LCD goodness

Sat Jan 11, 2020 2:10 pm

Right, of course!

Sorry for being a bit daft :lol:

aBUGSworstnightmare
Posts: 1573
Joined: Tue Jun 30, 2015 1:35 pm

Re: Looking for 5" LCD goodness

Sun Jan 12, 2020 7:43 am

Just a note: remember the pull-ups!

Savage1ZA
Posts: 10
Joined: Fri Jan 10, 2020 3:03 pm

Re: Looking for 5" LCD goodness

Mon Jan 13, 2020 7:09 pm

Hi Guys (again),

Sorry - just ONE last question please... (and yes - I've got my pull-ups)

The CM3 development boards, has a 0.5mm, 22-pin FPC. On the Pi4, it is an 0.5mm, 30-pin FPC. That's all good and well.

What get's me however, is that the wiring is different?

Pi4, CM3
1 - GND, GND
2 - DN1, DN0
3 - DP1,DP0
4 - GND,GND
5 - CN, DN1
6 - CP, DP1
7 - GND, GND
8 - DN0, CN
9 - DP0, CP
10 - GND, GND
11 - SCL, N/C
12 - SDA, N/C
13 - GND, N/C
14 - 3.3V, N/C
15 - 3.3V, N/C
...
20 - N/C, SCL
21 - N/C, SDA
22 - N/C, 3.3V

I am a bit confused here. As the connectors are physically connected differently (different pin layouts) - it would be impossible to connect a DSI screen with a 15-pin cable (such as the OSOYOO), to a (standard) compute development board, right? The pins / connectors would need to be re-wired?

Given that DN0 and DN1 is switched, and the CN/CP and I2C is on different pins too - I take it I would need to wire the Compute's display port to the Pi4's standard (pins 1 thru to 15, with 16 to 30 N/C)? The reason why I am asking, is the screen is obviously wired to match a "standard" and that standard would be the wiring of the Pi3/4, rather than the compute?

Sure - it's not a big deal - re-wire the port and you're done. Just asking from a design perspective, as there's obviously cost involved to make a PCB only to have the PCB being not traced correctly :D A silly, but potentially expensive mistake that can easily be avoided in other words.

trejan
Posts: 1094
Joined: Tue Jul 02, 2019 2:28 pm

Re: Looking for 5" LCD goodness

Mon Jan 13, 2020 7:21 pm

Savage1ZA wrote:
Mon Jan 13, 2020 7:09 pm
I am a bit confused here. As the connectors are physically connected differently (different pin layouts) - it would be impossible to connect a DSI screen with a 15-pin cable (such as the OSOYOO), to a (standard) compute development board, right? The pins / connectors would need to be re-wired?
Yes. The CM dev kit comes with two adapters for the CSI and DSI ports so you could connect regular Pi camera/display to the CMIO board. See https://www.raspberrypi.org/documentati ... gnfiles.md

They were at one point seperately available at https://uk.farnell.com/raspberry-pi/rpi ... dp/2433318 but it looks like they're no longer stocked.

Note: The camera and display adapters are not the same!
Savage1ZA wrote:
Mon Jan 13, 2020 7:09 pm
On the Pi4, it is an 0.5mm, 30-pin FPC.
30? It is 15 pin on the regular Pi boards.

Savage1ZA
Posts: 10
Joined: Fri Jan 10, 2020 3:03 pm

Re: Looking for 5" LCD goodness

Mon Jan 13, 2020 7:29 pm

trejan wrote:
Mon Jan 13, 2020 7:21 pm
Yes. The CM dev kit comes with two adapters for the CSI and DSI ports so you could connect regular Pi camera/display to the CMIO board. See https://www.raspberrypi.org/documentati ... gnfiles.md
Perfect ty. Know what you're talking about.
trejan wrote:
Mon Jan 13, 2020 7:21 pm
Savage1ZA wrote:
Mon Jan 13, 2020 7:09 pm
On the Pi4, it is an 0.5mm, 30-pin FPC.
30? It is 15 pin on the regular Pi boards.
It's a 30 pin according to my Pi4 as well as the dev schematics (15 on each side of the connector) - I assume you get fancy 0.1mm cables can connect to all 30 pins (both sides). 16 to 30 are N/C (to accommodate the bigger conductor in the cable I assume), 1 to 15 are used.

Ref: https://www.raspberrypi.org/documentati ... educed.pdf

trejan
Posts: 1094
Joined: Tue Jul 02, 2019 2:28 pm

Re: Looking for 5" LCD goodness

Mon Jan 13, 2020 7:38 pm

Savage1ZA wrote:
Mon Jan 13, 2020 7:29 pm
It's a 30 pin according to my Pi4 as well as the dev schematics (15 on each side of the connector)
No. It is 15 pins. The pin legs extend out both sides of the connector for additional strength. The part number isn't listed on the 4B schematics but the 3B+ schematics list it as a 1-1734248-5. It is sold as a single sided 15 position FPC connector and the drawings show the pin extends out both sides.

If you look carefully into the slot then you'll see the retaining latch blocks the other side and it doesn't have the contacts anyway.

Savage1ZA
Posts: 10
Joined: Fri Jan 10, 2020 3:03 pm

Re: Looking for 5" LCD goodness

Mon Jan 13, 2020 7:52 pm

Well that's very deceiving :o Bad, bad, bad Raspberry Foundation!

Just tested continuity on a Pi4 (1-30, 2-29, 3-28, etc), and you are indeed correct. Very, very deceiving as far as the schematics goes!

Need a right-angle connector though, I'll jump on RS now and replace with a suitable 15-pin connector, before I forget. Thanks!

Savage1ZA
Posts: 10
Joined: Fri Jan 10, 2020 3:03 pm

Re: Looking for 5" LCD goodness

Thu Jan 16, 2020 3:30 pm

FYI for those interested - I got my 5" Osoyoo today, literally as they said - plug and play.

No issues what so ever. The back light is also controllable via /sys/class/backlight/rpi_backlight/brightness as documented on the wiki. Even at 100 though, the screen looks a tee bit on the dark side, but that could just be reflections / light conditions here currently.

Professionally packed. A rather pretty and comprehensive little set of instructions, the screen, standoffs and screws, and they even give you a little screw driver for the screws too.

For those interested, the unit is 8mm thick (pretty standard for a LCB + PCB) with a 10mm standoff (so 18mm in total). I will more than likely remove the standoffs for my specific application and I should then be good for a back to back (PCB to LCD) of about 12mm or so. Should fit in nicely with my 7mm tactile switches + button.

Personally, if this works for my application (and I think it should), I will be buying a lot of these screens in the future. It looks like a very professionally assembled unit.

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