Build your own Morrow Project CBR Kit

Assuming you want to make a prop vastly similar to this one, this post assembles all the parts, links and diagrams I can provide.

Penultimate Morrow Post

This is the threatened "How we designed them" post.  I'm going to try to make it short with lots of pictures.

The design process was exploratory and iterative, but it was framed into two distinct sections; the "on spec" preparatory work, then a firm commitment to build.  The only late adjustment in contract was pushing the deadline back.  Of course I was consulting at every step, floating lots of sketches and renders back and forth as ideas developed.

As is usual with such things, it ends up being as much compromise and circumstance as it is art and science.  We were always aware of how things should "really" be both in the world of the Morrow Project and in the real world we pretended this project might exist in.  We chose to go in different ways not due to ignorance, but due to need.

Medkit Preview

Still waiting on the final selector knob, and the Mysterious Part that does all the healing and stuff (Shapeways order sent in just before the holidays).

But outside of those, and the associated wiring (because the Mysterious Part just had to have some LEDs put inside it!) the Medkit is done.

I'll take some nice pictures soon.  Until then, these will have to do;

 

I didn't take a lot of work-in progress shots either, sorry.  Anyhow...boring text stuff (but not very much of that either) below the fold:

Stop Casting Porosity!

Volpin makes it look so easy.

The difference is between being able to stumble through all the steps, and being able to do them with confidence and control.  I made a better box mold and a much better slush-cast for the Medkit body, and the lid fit first try.  But there is a bit of alignment still needed and I did have to Dremel out the lid a bit to fit the electronics.  Which means I'm far below the level where I would be offering a kit to other people!  Heck -- my panel lines are still barely acceptable.

 Next project I have to mold I want to try a jacket mold.  I'm tired of going through so many bucks worth of silicone, and the mold boxes I've been doing are barely good enough to keep the molds from folding over, turning my boxes into parallelograms. 

I'm finally seeing the end of this.  Still waiting on custom-printed knobs from Shapeways, have another couple lines of code to make the capacitance-sensor triggered "injector" look right, and of course solder some minimal components into the Medkit.  Oh, and print out the data plates and so some touch-up paint.

Which sorta of segues into an attempt at a schematic for the CBR kit:

I can't vouch for the accuracy of this.  I didn't exactly draw up a schematic before I started soldering, nor did I document that well during the project.  Mostly I opened up the appropriate datasheets and made the appropriate connections on the spot.

In the upper left is a basic 7805-based regulator.  I left the power switch off the diagram.  Below it is the 6-pin programming header that works with my in-system programmer.  Left of center is a minimal Arduino, essentially; 22 kHz resonator, power and ground.  There's actually a .1 uf filter cap across the power leads I didn't bother to draw in.  And some people hold RESET down to ground with a 1 meg resistor but this didn't seem to be necessary.

The important part is the Supertex HV5812, which I found at Mouser; a 20-channel high-voltage driver designed for use with vacuum fluorescent displays.  Like the Soviet-made, old-stock ILC1-9/8 eight-digit, seven-segment display I am using.  I found those on eBay and they were shipped from the Ukraine (cheap, too!)

Above the HV5812 is a Recom DC-DC converter also picked up at Mouser.  It works, but just barely; 24 volts is low for the VFD, which really wants 30-60V.  It also wants a voltage-controlled AC filament voltage, but a small resistor works well enough for this application.  To the right of the Recom a power Darlington (the venerable TIP120) is operating as a switch to (over) drive the poor speaker with nasty square waves.  No attempt at a DAC or waveform generator of any kind here.

Two of the AVR pins are being used for a capacitance sensor using the Arduino library (many AVRs will do capacitance sensing natively as well, which is a more efficient way to go if you have lots of pins and want a fast reaction time).  The indicator lights (20 ma LEDs) are all running off PWM channels, and the two control inputs (button and rotary switch) thus are on the otherwise unused analog inputs.  The rotary switch is using a resistor ladder, thus allowing a single pin to detect a larger number of different switch states.

As circuits go, its actually pretty simple.  Or, rather, no part is complex; it is just a melange of different simple circuits.  The HV5812, for instance; high voltage is supplied to Vpp and the regulated 5v to Vdd, but the four control lines (clock, blanking, strobe and data) are just fed any four arbitrary Arduino digital I/O lines.  Wire up which ever is convenient and then assign them the right pin numbers in code.  The outputs are the same; I pretty much wired them one-to-one to whichever VFD pin was nearest, and then solved the assignments in the lookup table.

The Morrow Progress

The CBR box is mostly assembled, and I've been coding up the behavior.  As is my wont, I've been thinking about the programming process.

But here's a pic:







Why is the pic so blurry?  Explanation and more boring text-ty stuff below the fold.  Plus more pics of me soldering things.

Cyber-Poverty

It's like something out of William Gibson.  More and more, in more and more places, "high tech" (aka electronics) is being worked on not in spotless labs with ranks of test equipment, but with rusty screwdrivers while propped precariously on top of a milk crate and surrounded by empty boxes of Chinese take-out.

It is a matter of perspective.  Technology has always needed to be patched and salvaged.  It has been happening from well before the days of background bicycle mechanics, probably way before the days of itinerant tin-smiths.  We just haven't (or at least some of us haven't) quite caught up on our Future Shock and we just aren't quite used to seeing shade-tree mechanics and third-world repairs and improvisations done to things that have LEDs and microprocessors and other digital parts.

Oh, yeah.

My laptop crashed, with my only copy of the software I was writing for the Morrow Project boxes.

Rant, and pics of things being soldered, below the fold.

Oscar Wilde does Electronics

He did describe the event himself, but it is more usually told as a story; Oscar comes down to lunch one day and a friend of his asks, "Hard at work all morning, were you?"

To which the novelist and playwright responded "Indeed.  I just inserted a comma."

After lunch he vanishes back upstairs and is not heard from until dinner.  At which point the same friend asks "Another productive session, I hope!"

Unperturbed by the sarcasm, Oscar replies, "Most productive.  I deleted the comma I had inserted this morning."

Well, Oscar's excuse was that he was a perfectionist.  My excuse is procrastination.  Plus a middling amount of physical and mental exhaustion from opening weekend.  Being both a designer and a show operator takes a lot out of me mentally and emotionally.  And the long hours (and short rations) don't do much good for me physically, either!


So this morning, I inserted a resistor.