Greeting earthlings. If you follow the channel, you know about my new addiction
for the overly complicated Twis-Lite switches and Roto-Tellite indicators that were used in
the Apollo ground control consoles. It’s a malady that I contracted after watching Fran Blanche's
episode on this very switch. We went all over the incredible features of these switches and
indicators in a previous episode, and at that time I had already acquired a little collection.
Well, thanks to more eBay sleuthing and donations from several subscribers, my collection has grown.
So one half is purchased, the other half is actually courtesy
of my viewers, thank you very much. And, you know the channel, we just won’t
sit there and admire them, we want to use them! So, what about making a little Apollo-inspired
control panel? As we’ve seen, the Twist Lites were used in droves in the Houston consoles.
And the launch room designers in Cape Kennedy went nuts with the Roto-Tellites.
But they mostly used standard toggle switches. I suspect because it’s very
hard to tell if a Twist-Lite is in or out, and they often needed 3 positions anyhow.
There are still a few examples of consoles with both, like this liquid
hydrogen tanking computer, this command input console, or this hydrogen storage alarm panel.
Also, not having NASA budgets nor rockets, we probably should set our sights on imitating
a more modest item, like a Ground Support Equipment box, or GSE as they called them.
So I went to pay a visit to our sole remaining surplus store in the Valley, Excess Solutions,
in search of a suitable enclosure for the project. And for a mere $25, I came home with this.
What do we have here? This is a micro BERT model 5575B, which actually I acquired not for the BERT
itself, but more for the case. It actually still works, but this is meant to test T1 lines - I
mean who tests T1 lines anymore. And of course there is no T1 line, but if I just put this - it's
missing a few screws - and put that, that will be my very very short T1 line. Yeah, it gets it!
For the telco-curious, a T1 line dates back to the copper based telephone era. It is a fancy name for
a regular twisted copper phone lines pair used to transport 24 digitized phone lines at 64 kbits/s
each, for a whopping total of 1.5 Mbits/s on plain copper wire, on runs of 2 km between repeaters.
So that was the first big upgrade to digital coding of the basic phone carrier plant,
which gave it a times 24 bump in capacity. It was usually decoded and broken into individual lines
on a type 66 wiring block at the customer. But here for this demo I just use the one
long cable I had on hand, which is the one between my teletypes. It will run on basically anything.
Okay, now if I put a frame it gets happier, and if i go to B8ZS it's all green. So it still works
except on the LCD, the back light doesn't work anymore. So inside it's not bad.
Here, nice power supply. There is a Z80 processor in there. The parts are dated 1990,
and there's some good analog electronics. But that's not what I bought it for, so we're going to
take it away. So what I actually bought it for, is as a box for
a front panel. Which I've made right here out of - here, I worked really hard - and
that was machined out of an HP panel blank - I guess. It's nice steel.
And what I want to do with it is, I want to put my
Apollo switches and make a ground control box. And they go like this, right in there.
It's really neat, all you have to do is machine a slot, and then they fit. And then you have the
bracket from the back - the a clip from the back that will [hold] them there. And
I have one for my Roto-Tellite. And here we go! And I'll actually reuse the transformer down there
to power the lights. So here are my first two buttons. The first one is a double state one, it
will go on as soon as it is plugged in, like so. And then, when you turn the rest of the platform
on, you have the second part of the switch that activates. And then here's a System Go button.
So here it is all put together in this Christmas tree color arrangement,
which the best I could do with the limited supply of color filter caps I had.
Next problem was the labels, which normally are engraved at the back of the sliding
transparent part called the lens. Fortunately I managed to find some new old blank lenses.
Instead of engraving, I simply used my trusty labeler, which not only can label on transparent
film, but also can print with a mirror inversion. I soon had a nice collection of inverted labels.
So here on the legends I have only two original ones, which were actually donations from viewers.
It's the System Go button, this one is too good. And the lamp test push button, which of course
does lamp test over here. And all the rest I have made by printing labels on transparent film in
mirrored fashion, and then putting it at the back of the lens. Well, it's pretty convincing I think.
So they almost all work, and the self-destruct is in red of course.
Except this one, I'm short of - I have the actuator, but i don't have the switch. So
this one is missing one switch. I need to find one more to complete the panel.
And other than that, you can have fun with your buttons!
The wiring was a real pain. I can hardly imagine the work that went into the real
panels. Note that you need to use diodes for implementing the lamp test functions.
If you had no diodes, the lamps would be all connected together in normal usage.
They had also thought about this, and provided a little add-on module that you’d clip in-between
the actuator and the switch modules, and that just contains diodes. This way you could keep
your wiring flight rated without the diodes dangling around like in my implementation.
The other thing that you notice right away,
is that it's pretty hard to tell when a button is pushed down and when it's pushed up, because it's
exactly the same thing. So that's of course why they didn't use them that much in the launch room.
They had toggles instead, because you can't really tell if they are on or off. One way to do
it is with, of course, the light. And so this one tells you if you have power to the whole thing.
But for example this one you can turn it in two colors.
And and the way to do that is to cross wire the - actually not cross wire.
So the way you're supposed to do that is, you put the light covers in a diagonal pattern and you
power up those two for the green and those two for the red. So that's one way.
The second way is to go do this kind of thing. And they were
a lot of them that were wired like these. So you order a dual segmented front display,
and then you put two reds and two greens. And so you have actually four states:
the green, the red, both and nothing. In this case it just toggles. But other than that,
you know, the only way you can tell if it's pushed or not is because of the light.
I was stumped for a while on how to make the roto-tellite legends, until I remembered that
I still had some lexan sheets to make canopies from the days I was building RC gliders.
They miraculously were the perfect thickness.
It was just a matter of cutting them on the paper cutter, and use the same inverted transparent
label technique to replace the originals. They just slide in and voila, Apollo themed indicator.
I did not have colored diffusers for the Roto-Tellites,
so I just used LEDs. For the reds, I found some commercial bulb replacements,
and for the greens I just made my own by sticking LEDs in the socket of dead lamps.
So, of course, on my own, I need a resistor on the other side. On the commercial ones
it's all included, there's a little regulator, so it's very convenient. But
unfortunately I couldn't find one for the green.
So here it is, it's all functional, it's put in my BERT box. So we replaced one useless box with
another useless box, but I think it looks pretty. And it's powered by the original transformer,
so you don't need to supply any outside power for the lights. The idea is that it's hooked up
to this 50 - uh - 25 pair, 50 lines CAT3 cable. That itself hooks up to a jumper block, block 66.
And then you would just hook your experiment into here, and access the switches easily.
Other than that, I put some goofy labels which are actually original labels from the
original Apollo panels. Well, you can turn it on, and play with your system.
Alright, I think we sure made that T1 test box take a step back in time.
But it’s still missing the final touch. Remember our GSE equipment
NASA asset tag? Nothing that a little bit of Adobe Illustrator couldn’t reproduce,
and it turns out Avery Labels can print them for you online on imitation metallic asset tags.
All right that should be the finishing touch, my Avery labels have arrived.
Oh! Nice! Turned out pretty good actually! So the label is kind of big, so I tried to
put it on the front panel, but it's really not meant for that. And then I tried to cut
it up in smaller pieces, but nothing really made any sense. So it went where it's meant to be,
on the case. Usually it's at the back or on the side. But so we can see it, it ended up on the top.
So this is now an official prop. We're all complete with an asset tag - NASA asset tag.
And hopefully in the next episode we'll do something more substantial, but I love building
props - heck, I built an entire R2-D2. So that was a lot of fun, and functional props is even better.
So thanks, for watching, and see you in the next episode!