Blast from the past... Dacta 9750 Interface A. Any more modern software?

[DadScientist]

Hi all,

As I struggle with running bigger motors/ more 'stuff,' I hit upon the idea of using some of the older battery boxes that hold 3 'C' cells. I can tie two of them together in series, get the 9V that I need, and it should theoretically last a lot longer than the AAs that I've been stuck with. As it happens, I also have an old 9750 set. Long story, but it has the blue plastic case, with all of the wires, some of which are even color coded. (Grey, obviously, as well as red, yellow, and blue.) All of the parts are present and accounted for... light bricks and their holders, optical sensor and encoder wheel, touch sensors, etc. Instructions are basically untouched.

And, I have the old interface A, and the circuit board that used to get shoved into an Apple IIe. (I think it was a IIe, I could be wrong.) And I figured, if I was going to go with all the vintage battery boxes, that the vintage interface might fit right in. BUT, I don't have a IIe handy, and don't really want to turn this into a deep dive into computing from my childhood.

So, I was wondering if there were any contemporary solutions for driving the thing with a more modern computer.

This would mean cracking open the shrink wrap on the electronic part of the set, which I haven't been able to bring myself to do. I can't even break up the box with the parts... I don't need any of them desperately enough to feel ok about separating any of it, unless/ until I can think of a good use for them. But as I start to get deeper into the robotics stuff, it might be a cool option to have. Especially if it can handle powering higher-load motors and such without getting fried.

Edited May 3, 2025 by DadScientist
spelling and syntax

[Jurss]

Maybe this helps

 

[Toastie]

Welcome to the right side of happy computing! And welcome to the board.

(@Jurss I believe that thread is for 9751, Interface B)

 

Sure enough, there is a plethora of things you can check out regarding LEGO Interface A. A good starting point is Evan Koblentz' (@evank) website: https://www.brickhacks.com/

Lots of links to be found there!

Here on EB are also a couple; here is one:

It depends on what you define as "more modern computer". I use Dosbox-X on my win11 laptop running QBasic/QuickBasic, USB2Serial or USB2TTL converter; on the other side, you'd need a serial2parallel converter, or a TTL2parallel converter, see thread above. Here are a number of QBasic programs (and other languages) here for some LEGO interfaces:

https://bricksafe.com/pages/Toastie

I also made programs for “era compatible” computers such as the TI99/4a, Atari 1040, IBM XT, Amstrad PCW9512, Sinclair ZX81, and Sinclair Spectrum … see Evan's site.

Here is another cool project: https://wiki.lvl1.org/Lego_Interactive_Interface-A_Driven_via_Arduino

But there is more, there always is: Here for example: Tom's page https://lgauge.com/

Have fun!

All the best
Thorsten

 

Edited May 3, 2025 by Toastie

[evank]

Hello @DadScientist and welcome to the rabbit hole of 1980s computer-Lego control!

Where in the US are you located? I'm in NJ.

Toastie knows more than me about the modern stuff; my specialties are 1. teaching people how to use the original system and 2. actually building cool stuff based around it.

 

[DadScientist]

Hi All!

Sorry for the lag, it's been a crazy couple of months. 

I'm close to Boston. 

I'm not up on a lot of the older stuff, or the modern stuff, yet. It's all in process. Most of my projects have involved mounting brushless motors, without blowing up the build. I've had mixed success, but ongoing progress. So, that's exciting. 

I'll dig into some of those resources, thanks all!

[evank]

I was just in Boston a couple of weeks ago.

Feel free to reach out to me anytime you have questions about the 1980s eight-bit Lego electronics. My schedule is pretty flexible.