Your sync method sounds reasonable. If it doesn't work, maybe consider
Stephen Adolph's hardware hack to send a signal to the gluelogic to start
sending data .

Yes, M100 LCD is black and white only, zero shades of gray. I believe the
Model 100 screen is 240x64 pixels. Since you are using a 128x128 chip, you
may want to look around and see if anybody you know has a Tandy 200 as
those have 240x128 pixel screens.

 Both Firefox translate and Google translate had some difficulties with
that German article, but I think I got the gist. One question: Why does he
say the RAM chip will need to be replaced often?

—b9

On Tue, Feb 24, 2026 at 2:59 PM Scott McDonnell <[email protected]>
wrote:

> Yes, the scanning and timing would be done in either a CPLD or a small
> micro. Probably will cheat and use a small micro just because it will have
> the clock, etc.. already and keep parts count down. And sadly, modern
> micros are cheaper than PLDs or discrete chips.
>
> My current plan is to use different pulse widths for timing information.
> The micro would continuously scan. At the beginning of the scan, it will
> output a longer pulse to indicate frame start. Then just shift the pixel
> data. I may end up inserting a new line sync if necessary, but I don't
> think I will need to since we can just count pulses from the start point.
>
> Some level of gray scale is possible by repeatedly testing a bit and
> determining the time it takes before it fully decays and flips to zero. But
> that is irrelevant to the Model 100, I think (can't do greyscale on the
> Model 100 LCD, right?)
>
> On the C64, I was going to use the 4 direction lines for grayscale and the
> fire button for the sync pulses.
>
> The idea is that if I can make this work on a Model 100, I should be able
> to make this work on an 80s robot.
>
> Here is some information on the concept. Lots of older magazine articles
> about it as well.
>
> http://www.kurzschluss.com/kuckuck/kuckuck.html
>
> Scott
> On 2/24/2026 5:14 PM, B 9 wrote:
>
> Cool idea! I don't think the Bar Code Reader port has enough (any?) output
> ports to address the RAM, so I'm guessing your  "glue logic" is going to
> spew bits to the BCR, right? What's your thought on synchronizing with the
> M100?
>
> Whether this ends up working or not, I'd love to see whatever you come up
> with.
>
> —b9
>
> On Tue, Feb 24, 2026 at 8:33 AM scottgmcdonnell <[email protected]>
> wrote:
>
>> It certainly would. And it has all the signals required to not need much
>> additional circuitry.
>>
>> But it is more of a 'because I can' excercise. Speed is not a major issue
>> for this. The Model 100 serial speed at the barcode port is capable of
>> speeds much faster than such a camera.
>>
>> As well, this is not a realistic justification (doing 1980s marketing
>> roleplaying here), but the average person would be more willing to plug a
>> peripheral in to the barcode port. The system bus feels more 'advanced' and
>> "Radioshack technician" installable.
>>
>> Not that this is 1984 and we are making an actual product or dealing with
>> a "typical user" today.
>>
>>
>> Anyway, just for novelty as well as the ability to make one circuit that
>> works with both the C64 and the Model 100.
>>
>> Scott
>>
>> Sent from my T-Mobile 5G Device
>>
>>
>> -------- Original message --------
>> From: "Alex ..." <[email protected]>
>> Date: 2/24/26 8:51 AM (GMT-05:00)
>> To: [email protected]
>> Cc: [email protected]
>> Subject: Re: [M100] DRAM camera capture on the Model 100
>>
>> Wouldn't the system bus interface be your best bet for speed?
>>
>> On Tue, Feb 24, 2026 at 5:14 AM Scott McDonnell <
>> [email protected]> wrote:
>>
>>> In my robotics group, we have been talking about an old concept of using
>>> a DRAM IC as an image sensor.
>>>
>>> Essentially you take an old DRAM IC in ceramic package with the metal
>>> lid and knock off the lid. You pre-charge the DRAM with all 1s and then
>>> as light hits each cell, it drains the capacitor and will flip the bit.
>>> The brighter the light, the faster it flips.
>>>
>>> A 4164 DRAM of this type has two 128x256 arrays with a small gap in
>>> between. Generally one would just use 128x128 of one half. The camera
>>> lens would be arranged to focus on that. A 4164 DRAM is a 1 bit by 64K
>>> DRAM. Just one digital output.
>>>
>>> Now, from robot vision, my brain started working out how to off-load a
>>> bunch of the scanning and glue logic, I came to the conclusion that I
>>> could capture an image through the joystick port of a Commodore 64.
>>>
>>> And then I thought, Hmm, this should be possible on the barcode port of
>>> the Model 100 as well...
>>>
>>> On the joystick port, I was thinking a frame sync and the one digital
>>> bit. This could be modified to use a longer pulse to indicate a frame
>>> start on the Model 100.
>>>
>>> This could be used to scan in a document or take very, very low
>>> resolution images on the Model 100.
>>>
>>> Doing it through the barcode port would mostly just be for the novelty,
>>> of course. The printer port might be the better option.
>>>
>>>
>>
>> --
>> Disclaimer: Any resemblance between the above views and those of my
>> employer, my terminal, or the view out my window are purely coincidental.
>> Any resemblance between the above and my own views is non-deterministic.
>> The question of the existence of views in the absence of anyone to hold
>> them is left as an exercise for the reader.
>> The question of the existence of the reader is left as an exercise for
>> the second god coefficient.  (A discussion of non-orthogonal, non-integral
>> polytheism is beyond the scope of this article.) Thanks /usr/games/fortune
>>
>

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