Arduino Due, iMac and NBTV

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Arduino Due, iMac and NBTV

Postby kd6cji » Fri May 04, 2018 2:43 pm

This is "electronic" NBTV based on Arduino Due. Sketch supports 24,30,32,48,56,60 and 64 line video color and monochrome. NBTV signal is generated by NBTV Video Converter that runs on iMac and supports the same modes, taking as an input any mp4 movie or images or video camera (internal and external). Here is a short video of 64 line color video displayed on 96X64 pixel OLED display. It looks much better than on video...
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IMG_2779.MOV
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Re: Arduino Due, iMac and NBTV

Postby kd6cji » Mon May 14, 2018 9:37 am

Some progress, made it almost neat. No more long wires. It is almost a pocket televisor.
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image.jpeg
image.jpeg
image.jpeg
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Re: Arduino Due, iMac and NBTV

Postby Andrew Davie » Mon May 14, 2018 5:04 pm

Neat... good job!
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Re: Arduino Due, iMac and NBTV

Postby DrZarkov » Wed May 30, 2018 11:06 pm

Impressive! Could you post more details, how it works?
I still have not updated my Macbook from MacOS X 10.6 to a newer system, in order to run your NBTV software, which is PPC-only. So you wrote a new NBTV-converter for the Mac?
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Re: Arduino Due, iMac and NBTV

Postby kd6cji » Thu May 31, 2018 1:03 am

Yes, I have a new version of NBTV converter. It uses latest AV Foundation frameworks and should run on 10.10 or later. It generates both monochrome and color video at 30 to 128 lines with 6.25, 3,75, 12.5 and 15 frames per second. For higher rates and more than 32 lines sound card needs to support 96000 samples per second sampling rate. Arduino part uses 96X64 full color OLED display and capable of displaying 32 and 64 lines video in B&W or color at up to 15 fps. This morning I tried a larger 128X128 pixel display in hope to do 96 and 128 lines, but it turned out to be too slow compared with smaller display, so that was a failure. I am attaching an Arduino sketch and NBTV converter zip files if any one interested to play with. Arduino Due board uses its internal ADC converters to sample video, so interface is very simple.
Attachments
NBTV Video Converter.zip
Mac OS X App
(370.07 KiB) Downloaded 87 times
NBTVTEST0_P.zip
Arduino Due sketch
(3.13 KiB) Downloaded 86 times
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Re: Arduino Due, iMac and NBTV

Postby kd6cji » Sat Jun 02, 2018 4:53 am

Made some minor bug fixes in both NBTV Video Converter and Arduino sketch. Here is the latest versions and short video.
Attachments
NBTV Video Converter.zip
Mac OS X Application to generate NBTV video
(185.49 KiB) Downloaded 77 times
NBTVTEST0_P.zip
Arduino Due sketch to display 32 or 64 line B&W or color NBTV video on a 96X64 pixels OLED display
(3.05 KiB) Downloaded 88 times
IMG_2830.mov
Arduino Due displaying 64 line color video
(8.79 MiB) Downloaded 83 times
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Re: Arduino Due, iMac and NBTV

Postby kd6cji » Fri Jun 08, 2018 7:50 am

Here is version 1.2 of NBTV Video Converter.
* fixes aspect ratio for movies, video and images
* NBTV video aspect ratio can be selected 1:1 or 4:3
* added vertical scan for NBTV video
Attachments
NBTV Video Converter.zip
Version 1.2 for macOS 10.9 and above
(187.14 KiB) Downloaded 71 times
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Re: Arduino Due, iMac and NBTV

Postby kd6cji » Sat Jun 09, 2018 4:46 am

This is how vertical scanned video looks on Arduino Due NBTV
Attachments
trim.927D439F-8CB8-492A-B436-463EB59CDB04.MOV
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Re: Arduino Due, iMac and NBTV

Postby nanowaver » Mon Jul 30, 2018 11:41 pm

It's hard to be sure from the photos but the usual input circuit for the Due ADC pins is

1) incoming signal.
2) electrolytic cap (at least 10uF) negative side to input.
3) the positive side of the cap is connected to the centre point of two 10K resistors in series. The other side of one 10K goes to Gnd. The other side of the second 10K goes to 3.3V on the Due board.
4) the centre point pf the 10K resistors is then also connected via a 100R resistor to the ADC input pin.

There seem to be two inputs (video and line sync?) so the above circuit is needed for each ADC input.

The OLED connections are:

OLED Due
-----------------------
Gnd Gnd
VCC +5V
SCL middle pin on the Due SPI 6 pin connector which is closest to the Atmel CPU chip (SCK)
SDA middle pin on the Due SPI 6 pin connector which is furthest away from the Atmel CPU chip (MOSI)
RES 26
DC 24
CS 22

I have got the sketch running on my Due and showing the start-up screen but haven't tried it yet with a standard NBTV signal
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Re: Arduino Due, iMac and NBTV

Postby nanowaver » Thu Aug 02, 2018 12:02 am

Further to my last post, Sergei has confirmed the ADC input connections, but suggests 68K + 12K rather than my guess of 10K+10K.
ADC0 is used for monochrome signal input but if a separate sync is available on ADC1, it will be used. For colour pictures, both ADC0 and ADC1 are used

Baz
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Re: Arduino Due, iMac and NBTV

Postby FlyMario » Thu Aug 02, 2018 3:22 am

Well that is very cool.
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Re: Arduino Due, iMac and NBTV

Postby nanowaver » Fri Aug 03, 2018 6:28 am

I can now display a standard NBTV (32 lines, 12.5 frames/sec, 3:2 aspect ratio) 8 level grey scale as generated using the triple waveform generator described in the NBTV Handbook. I'm feeding the output of the generator directly into ADC0 via Segei's input circuit and using a LM1881 sync separator chip to generate sync pulses to feed into ADC1 (again via Segei's input circuit)

Baz
Attachments
IMG_2549.JPG
IMG_2549.JPG (69.23 KiB) Viewed 1444 times
IMG_2548.JPG
IMG_2548.JPG (57.02 KiB) Viewed 1444 times
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Re: Arduino Due, iMac and NBTV

Postby nanowaver » Sat Aug 11, 2018 6:30 am

The NBTV images shown in my last posting are actually built up in mirror image form. So the vertical picture lines are actually assembled starting on the left hand side of the image and finishing on the right hand side. This is opposite to the NBTVA image standard but can easily be corrected by a simple change to the Arduino sketch.

Find the part of the sketch called void display_mode()

This finishes with the lines:

tft.fillScreen(BLACK);
Timer3.start(pixel_duration);
}

Simply insert the following line before the Timer3 command:

tft.setRotation(1);

The NBTV image can now be viewed correctly when the OLED is rotated such that the pins are at the bottom of the screen area, rather than at the top.

Baz
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Re: Arduino Due, iMac and NBTV

Postby nanowaver » Sat Aug 11, 2018 7:14 am

OOps! The picture is still being built up starting from the left hand side! If I turn the OLED so that the pins are at the top again, the picture is being built up from the right hand side but each line is mirrored top to bottom. It should be possible to correct that by reading out the contents of the line buffer in reverse order.
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