qr codes QR Code test on CRT

[Thomas Jentzsch]

Hi,

after creating a QR code generator, I would like to do some testing on CRTs. I have attached three versions, with increasing error correction. They randomly produce 16 different short texts as QR code. Press fire to create a new one. The left difficulty switch changes the vertical position.

 

So if you own a CRT and a flash cart, it would be very nice if you could do some testing. My own CRT can scan version L which should be the hardest one to scan. But only if the contrast is good. If the contrast is too low, all versions fail.

 

Level L(ow) has the lowest error correction, so this should be tested first. If your phone is having problems (even after adjusting contrast), please try M(edium) next. And if that still fails, try Q(uality). Please try multiple QR codes on each level you test since there are 128 possible combinations. 

 

Looking forward to your results! If you can, please give some details about your CRT (model, size, brand, flat screen...).

QR Code Generator L.bin QR Code Generator M.bin QR Code Generator Q.bin

Edited April 12, 2021 by Thomas Jentzsch

[alex_79]

All 3 work fine on my 14" HITACHI CRT, using a Light sixer through RF. I tried several QR codes with each rom.

I kept the TV settings I normally use (Contrast ~50%, Brightness ~25%, Color ~50%)

[Kirmok]

"L" version works fine (ok 100% of the trials) on Toshiba CRT  tv , M and Q work too. RF video output, contrast at factory setting.

Also ok for all 3 versions on Commodore 1084 PAL, via composite (mod) video output.

Both crt 14'

Edited April 13, 2021 by Kirmok

[+Andrew Davie]

I tried and failed with all three.

Using a QR code app on an Android phone. It worked OK with sample images shown in the other thread.

But with my CRT - a 14" dual-standard, running an NTSC image at 60Hz -- no luck at all.

I took a screenshot. I guess my monitor resolution is crap.

 

[Thomas Jentzsch]

Looks to me mostly like bad contrast. Have your tried adjusting your monitor and/or your camera settings?

 

Resolution might play a role though too.

 

Edit: I took your screenshot (BTW: Which error correction does it use?) into Paint.Net and adjusted contrast and brightness. Even then it was almost impossible to read the QR code. The app only picked up the code once, which must have been luck. 

 

But after I unfocused the image quite a bit, it suddenly worked. I guess the visibility of the dot mask is causing the problems here. Maybe step away from your monitor. Contrast is still a bit low, with more contrast it works better (Note: not on the white background here, but when you click on it and have a black background).

 

Edited April 13, 2021 by Thomas Jentzsch

[Thomas Jentzsch]

Any more test results?

[+Andrew Davie]

Very interesting; I think you are correct about too-close, seeing the phosphor dots.

I redid the experiment with all three error correction versions - same monitor, no adjustments. This time, I started with the code in the detection square, nothing. I pulled back, and at about 50cm ALL of them were detected consistently and correctly. Even though the code was thus quite small on the camera screen. So, lesson is -- don't be too close

 

[Thomas Jentzsch]

5 minutes ago, Andrew Davie said:

So, lesson is -- don't be too close

Or use a bad camera.  

[+fdr4prez]

11 minutes ago, Andrew Davie said:

Even though the code was thus quite small on the camera screen. So, lesson is -- don't be too close

 

5 minutes ago, Thomas Jentzsch said:

Or use a bad camera.  

I thought the lesson was "bigger is not always better"  

[xeex]

No problems with Level L here (or the others). Used the 2600 MiSTer core on a Sony PVM 1354Q.

[+McCallister]

Tested multiple Level L's on the following:

 

2005 Phillips 27" : works

1998 Sony 13": works

1987 Toshiba 13" w/tube starting to fail: works

1970's Panasonic 19": works

Apple Monitor III: works great in glowing green ?

 

 

[Thomas Jentzsch]

Cool. Thanks a lot! I suppose the results so far prove, that size doesn't matter. At least in this case.  

[sarahtmonroe]

Thanks for sharing your QR Code generator project! That's pretty cool.
It might be a little late but I still want to mention that I have a CRT and flash cart, so I'd be happy to help.

[Thomas Jentzsch]

Thanks for offering your help, but I think the required tests are all done.

 

But since this is your very first AA post, may I ask why this rather obscure topic brought you here?

Edited March 18, 2023 by Thomas Jentzsch

[sarahtmonroe]

On 3/18/2023 at 10:32 AM, sarahtmonroe said:

Thanks for sharing your QR Code generator project! That's pretty cool.
It might be a little late but I still want to mention that I have a CRT and flash cart, so I'd be happy to help.

I'm sure you know that CRTs vary, but I have a Smart Engines model that should work well with your program. I'll give it a go and see what happens. I'm guessing Level L will be the hardest since it has the lowest error correction, so I'll start there and adjust the contrast as needed. I'll try to test out a few different QR codes on each level and report back with my results. Let me know if you need any other info - I'm happy to help!