The LaserBoy Thread

It was a kit advertised in Popular Electronics magazine; a pcb, bag of parts and a book.

The Timex 1000 was exactly the same thing but fully assembled.

It was a fantastic learning experience.

It came with 1K of memory on the board. That is 1024 bytes. There was a 16K module sold separately that plugged into the back on the edge connector.

If you watch the Netflix series Maniac with Jona Hill, Emma Stone, Sally Field... the settings and props are spectacular.

In one scene a guy is pulling parts out of a computer AI, reminiscent of HAL and the part he really needs to pull out is ..... the 16K Sinclair memory module. How many people do you think would recognize that?

I had a ZX81 back in the day as well. I wrote a circuit analysis program on it to aid in the design of my first phono amp. I got on my bike and made the 7 mile trip to Radio Shack multiple times to get all the parts.

I'm just gonna drop this right here.....

https://laserboy.org/text.mp4

James.

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Originally Posted by james

I put it out there because I have always loved computer generated art. That is the very reason I was attracted to computers in the first place back in the late 70s. As soon as I got my own computer, a Sinclair ZX81 ( https://en.wikipedia.org/wiki/ZX81 ) I wrote a program that drew Spirograph pictures. Then I got a Commodore 64 and did the same thing.

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That is way cool, James. I remember the Sinclair ZX80 when it first came out. A great inexpensive platform to learn and explore, it used Zilog's Z80 chip didn't it?

Yep! I believe it was a screaming 1MHz 8 bit processor.

One thing that made the ZX81 quite unique was the very structured way it interpreted its own version of BASIC. Most of the keywords that started a line of code were only one keystroke. The way lines of BASIC code were keyed into the editor was guided, so it was easy to not make any syntax errors. Another thing that was pretty crazy was that if you worte code that would break for numerical user input at the prompt, you could enter a full arithmetic expression with all the variables that you had already written into the code up to that point and it would take that as a text string and evaluate it even through multiple iterations of changes in the values of the variables you entered into the expression.

So when I wrote the Spirograph program, I could enter whole expressions for X and Y at the prompt.

When I got my Commodore 64, I just assumed it would work the same way.

Nope!

Quote:

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Originally Posted by james

One thing that made the ZX81 quite unique was the very structured way it interpreted its own version of BASIC. Most of the keywords that started a line of code were only one keystroke. The way lines of BASIC code were keyed into the editor was guided, so it was easy to not make any syntax errors. Another thing that was pretty crazy was that if you worte code that would break for numerical user input at the prompt, you could enter a full arithmetic expression with all the variables that you had already written into the code up to that point and it would take that as a text string and evaluate it even through multiple iterations of changes in the values of the variables you entered into the expression.

So when I wrote the Spirograph program, I could enter whole expressions for X and Y at the prompt.

When I got my Commodore 64, I just assumed it would work the same way.

Nope!

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Tell me about it!:)

The graphics capabilities of the Sinclair ZX81 were equally spectacular. You could plot pixels that were about a quarter of an inch square ⬛ on a white screen, 64 x 44 pixels!

Breathtaking!

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Originally Posted by james

The graphics capabilities of the Sinclair ZX81 were equally spectacular. You could plot pixels that were about a quarter of an inch square ⬛ on a white screen, 64 x 44 pixels!

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Right up there with a good old fashioned TI graphing calculator.:cool:

Did not realize the ZX81 would allow you to enter expressions as user input... That's actually really cool! Shame it only had 1K of RAM.

The Ohio Scientific Challenger 1P I started with was based around the venerable 6502 CPU. It had 4 K of RAM, which was more than enough for the silly stuff I wrote for it. Graphics were just as limiting as the ZX81 though - 24 characters per line if I remember correctly. (Ugh!) But you did have an assortment of shapes that could be poked directly to the video display area which was sort of cool. Monochrome only, of course.

It shipped with Microsoft Basic 2.01 in ROM. (That's why the ROM was so big - 8K!)

Adam