Ralph Taggart's Universal Televisor controller

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Ralph Taggart's Universal Televisor controller

Postby acl » Sun Jan 16, 2022 2:17 am

Following on from his ‘Romscanner’ Ralph Taggart has kindly donated to the club a number of starter kits for a ‘Single board Universal Televisor Controller’. Whist initially to be used with a Nipkow disc it can be utilized with mirror screw displays etc for the more adventurous experimenter. All the electronics are housed on a professionally designed and produced double-sided through hole plated PCB encompassing Peter smiths and Klaas Robers motor drive and LED display circuitry. This reduces external wiring. A separate display board facilitates mounting either discreet LEDs or LED ‘patches’ used in the automotive industry. The starter pack includes full documentation and sample NBTV files. Whist all components and the disk will need to be sourced separately the club shop has a supply of various semiconductors for this project.


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Lightbox and Controller blank PCBs
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Ralph Taggart's Universal Televisor controller

Postby acl » Sun Jan 16, 2022 8:08 am

A few photographs of my unit.Please note I built it 'open frame' so we can demonstrate at conventions.

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Rear view of the completed unit

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Front view of unit

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Fully populated control board

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Printable synchronizing disc
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Ralph Taggart's Universal Televisor controller

Postby acl » Tue Jan 18, 2022 1:47 am

Attached is the latest version of the handbook as written by Ralph. I hope this stimulates interest for possible constructors.

Regards Chris Lewis G6ACL

UTP_Manual.pdf
Latest Manual
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Ralph Taggart's Universal Televisor controller

Postby acl » Wed Jan 19, 2022 3:21 am

Ralph's televisor utilizes a reflective photo diode/ transistor in one package. Here the sensor detects the synchronizing pulses from the stroboscopic disc attached to the main disk. The advantages are that all synch detection is performed from one side of the disk making construction easier. It is important to ensure the strobe disk black areas are printed really dark to get reliable results.

Regards Chris Lewis G6ACL

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QRD1113 Detector pinout
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Re: Ralph Taggart's Universal Televisor controller

Postby Steve Anderson » Wed Jan 19, 2022 12:08 pm

A point worth noting, I've seen reference to the fact that some inks are transmissive to I.R...where I can't recall, maybe somewhere on this forum. So although the black printing appears opaque to our eyes, it may not be entirely so at I.R., perhaps resulting in lower amplitude pulses from the detector than expected. This is hinted at in Chris's last sentence above.

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Re: Ralph Taggart's Universal Televisor controller

Postby Harry Dalek » Wed Jan 19, 2022 7:38 pm

I know the problem well ................black is not always black IR light so the printer ink does not always work from memory a laser printer is the way to go ink jet a no goer white and black same no pulse the white and black will look the same ....i suggest experiment between your black ink and white paper and your sensor .
Also the printed disk if the print is not of the highest quality expect a jagged line so a varying pulse width same go's for any disk wobble same result ..all seems easy at first :roll:
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Re: Ralph Taggart's Universal Televisor controller

Postby acl » Wed Jan 19, 2022 10:18 pm

The scope doesn't lie. Yellow trace shows output from sensor whilst blue after passing through a Schmitt trigger. Reducing the sensor resistor to 2k2 resolved the problem. Thanks for your help lads.

Regards Chris Lewis G6ACL

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Re: Ralph Taggart's Universal Televisor controller

Postby Klaas Robers » Thu Jan 20, 2022 3:18 am

Is that the resistor of 10k that you changed to 2k2? That has a critical value. I would have designed a trimming potentiometer at that position. Yes, you have to set that only once after you printed your sync-sync and positioned your reflective sensor, but the density where you printed the sync-disc and the sensitivity of the sensor and the distance to the disc are all influencing the behaviour.

I was thinking how to adjust such a preset variable resistor without an oscilloscope. Not so easy with no more than a multimeter......

I recognise the transparency of black material. It was in 1970 at a laboratory in NL where I fulfilled my military service. We had a mechanical papertape reader, which did not work good enough. Then we converted it to an optical reader with 8 photo transistors and one small tubular incandescent lamp. To devide the light we had a small sheet of black plastic with 8 small holes in it. Papertape ho;e size. One hole for each of the data tracks. It did not work at all. And then we discovered that the black plastic was 100% transparent for the IR part of the light. There was almost no separation for the tracks. We then used some other plastic sheet, not black but dark green. And of course we checked the transparency for IR before we used it. That did the work.

From that moment I never thrusted black plastic to be black for IR.
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Re: Ralph Taggart's Universal Televisor controller

Postby Steve Anderson » Thu Jan 20, 2022 12:50 pm

Klaas Robers wrote:From that moment I never thrusted black plastic to be black for IR.

A prime example of that is the 'daylight' filter that the majority of I.R. remote control receivers are encapsulated in. It blocks visible light yet passes I.R., basically an optical low-pass filter.

The QRD1113 above is no different...

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