[vcf-midatlantic] A little electronics hack

Mark Whittington markwhi at gmail.com
Mon Sep 30 11:16:29 EDT 2019


Looks like someone on this list has already done the legwork on this as of
2016...

https://www.glitchwrks.com/2016/09/12/lego-logo-interface

On Mon, Sep 30, 2019 at 9:13 AM Evan Koblentz via vcf-midatlantic <
vcf-midatlantic at lists.vcfed.org> wrote:

> >> If you're interested in investigating further if you point us to
> schematics we can give suggestions.
>
> I am giving the box to Neville in early November (don't want to risk it not
> working before the Brickfair NJ event the first weekend of that month). He
> agreed to my request to make a schematic of it.
>
> The next step will be to have someone else take his schematic, build one,
> and send it back to me for testing. That'll prove that the box can in fact
> be built from just the plans. After that I'll post it on my website.
>
> A possible third stage would be to make modern improvements, if any ideas
> stand out.
>
> I'm only interested in the function, not in replicating the physical case.
> But what I would avoid is replacing the vintage computer with a
> microcontroller. I'm all for a better interface but strictly against some
> non-vintage computer experience.
>
>
>
>
> On Mon, Sep 30, 2019, 8:43 AM David Gesswein via vcf-midatlantic <
> vcf-midatlantic at lists.vcfed.org> wrote:
>
> > > >> It's called a 'crowbar' circuit.  Prevents things from burning up.
> > >
> >
> > What I normally called a crowbar circuit is the overvoltage protection
> > where it intentionally shorts the output of the power supply. This sounds
> > more like over current protection.
> >
> > > What are common reasons why those stop working? Neville and I didn't
> see
> > > any obvious signs of damage to it.
> > >
> > Either component value shift or failed component. You indicated that it
> is
> > driving the motors better than it ever has. It may also be your motors
> > are a heavier load than it was intended to drive.
> >
> > If you're interested in investigating further if you point us to
> schematics
> > we can give suggestions.
> >
> >
> > > On Sun, Sep 29, 2019, 1:56 PM Mike Loewen <mloewen at cpumagic.scol.pa.us
> >
> > > wrote:
> > >
> > > > On Sun, 29 Sep 2019, Evan Koblentz via vcf-midatlantic wrote:
> > > >
> > > > > Neville noticed something that I wouldn't have. The circuitry
> > contains a
> > > > > safety mechanism to shut off all power if the current jumps too
> high,
> > > > such
> > > > > as a kid inserting a paper clip. There's probably a technical name
> > for
> > > > that
> > > > > but I do not know it. Anyway, for unknown reasons this circuit was
> > > > kicking
> > > > > in! He jumped it with an equal-length wire. :)
> > > >
> > > >     It's called a 'crowbar' circuit.  Prevents things from burning
> up.
> > > >
> > > >
> > > > Mike Loewen                             mloewen at cpumagic.scol.pa.us
> > > > Old Technology
> > http://q7.neurotica.com/Oldtech/
> > > >
> >
>


More information about the vcf-midatlantic mailing list