Building Props for a Back-to-the-Future Time Machine - Part 6: The SID panel

My other blog posts on BTTF props:

  Part 1: Building a Flux Capacitor
  Part 2: Building the Time Circuits
  Part 3: Building the Speedometer
  Part 4: Building the Analog Gauges
  Part 5: Building the TFC switch

This is now the last of the Time Machine props that I am building: The "SID panel" (Status Indicator Display) which sits in the DeLorean behind the drivers seat (right from the Flux Capacitor). It does not have any obvious function, but it looks cool in the movie when Marty approaches 88mph and you can see behind him, more and more of the 200 LEDs in this panel starting to light up: One row (= ten) red LEDs, siz rows of yellow LEDs, and thirteen rows of green LEDs. The good thing is that these days LEDs are dirt cheap (like 100 for $0.99 at Aliexpress). The bad thing is that in the original prop, each LED is mounted inside a little plastic holder - and these holders cost like $0.50 a piece (and 0.5 * 200 = ... too much). But I never went for 100% accuracy, so I just omit these holders. With this, I think the whole SID cost me less than $15.

The construction of the enclosure is straightforward.

It was fun, to watch the laser cutter cutting the 200 holes, and the result is, of course, very precise.

Now that the enclosure is glued and painted, it's time to address the electronics. Unlike for the other BTTF Time Machine props, the matrix circuit (and, later, the Arduino programming) for the 200 LEDs is a little more complex. 

The LEDs are soldered onto three 9cm x 15cm PCBs, as a matrix.

The electronics is based on an Arduino Pro Mini (ATmega 328). The LED matrix is accessed by a decimal counter (CD4017) for the 10 columns (together with two MIC2981 drivers), and three chained shift registers (TPIC6B595, which can sink larger currents than the 74HC595) for the 20 rows.

The code require a few more thoughts: My SID panel will operate in two modes: 1) standalone and 2) connected (via serial) to the other Time Machine props, so it gets the information of the current speed from the speedometer - and it can adjust the LED activity to the speed.

In both modes, the LEDs are moving randomly up and down. In mode 2) the random activity is coupled to the speed, while in mode 1) a speed value of 40 is assumed. The up and down motion of the individual LEDs columns is, however, not independent. If, for a given column, the two neighbors are higher, this increases the probability for this column to rise. Also, if a column was rising before, the probability is higher for this column to continue to rise in the next step. When a column has reached its max or min value, it will sit there for a while (the time is, again, random) and then change it direction. All the probabilities mentioned here are speed-dependent, such that the overall activity also changes with the speed. At zero speed, the columns are typically only moving up to the 5th row, while at 88 on average more than half of the columns will go all the way up, into the red.

After spending too much time on BTTF forums, I concluded that I had to add some corrugated plastic pipe (of about 3/4" diameter) which is held by two P-clamps (I could not find any purple ones, like in the movie prop, so I had to settle for black), through which the power/serial cable coming from the TFC switch is led. 

Here, the final unit is operating on the back seat of my car (no, it's not a DeLorean...).

Related:

My other blog posts on BTTF-related props and pieces:

   - Building a Flux Capacitor

   - Building the Time Circuits

   - Building the Speedometer

   - Building the Analog Gauges

   - Building the TFC Switch

   - Building a Hoverboard and Charger

   - Building BTTF clocks
   - Building a BTTF Brick Stage (featuring the smallest Flux Capacitor)

Building Props for a Back-to-the-Future Time Machine - Part 5: The TFC Switch

My other blog posts on BTTF props:
  Part 1: Building a Flux Capacitor
  Part 2: Building the Time Circuits
  Part 3: Building the Speedometer
  Part 4: Building the Analog Gauges

Introduction

The TFC switch is the center piece of the time machine. It is certainly not as attractive as the Flux Capacitor, the Time Circuits, and not even as the Speedometer or the Analog Gauges. But it is the unit that turns all the others on and off.

The most recognizable elements are the handle (built from a battery terminal cleaner like the Lynx 3-in-1 battery brush, https://www.pepboys.com/lynx-battery-brush/product/9405475) which is mounted on a Dayton Drum Switch (https://www.grainger.com/product/DAYTON-Maintained-Reversing-Plastic-2X442, with the top cover replaced by transparent acrylics). Other than that, it consists of eight switches, one potentiometer, and two lamps, all in a Radio Shack project box (8 x 6 x 3 inches, Model Number 270-274). The labels are matching the other labels on the time machine pieces, either from a 1980's style label maker, or with a white Eurostile Bold Extended (or Microgramma Bold Extended) font on a red background.

Using the above links, one could simply buy all the pieces and get a very precise reproduction of the original prop. However, the drum switch alone costs more than $100. Like my other props, I want to build this thing from scratch, mostly using wood (plywood) and a laser cutter.

Building

I am starting by cutting all pieces from 3/16" plywood with a laser cutter.

Here are the pieces for the bottom box, together with the switches and lamps. I got all the switches and lamps from Aliexpress. While the lamps in the original prop have beautiful jewel lenses (which you can still get ... but not cheap), I used two LED lamps of similar size with simple, but good-looking plastic covers.

The box is glued and painted.

Here are the pieces for the Drum Switch.

First, the holders for the rod are painted black.

The side pieces are glued onto the base plate.

Some wires and PCB pieces are used to make the inside of the switch look interesting. 

Now, the challenge is to bend the acrylics plate to shape.

The first half went really well...

... but the second half became really ugly. The acrylics bent weirdly, and at one screw hole it broke. This will be redone later.

Some labels are made using a Dymo label maker, and the others are printed on 4"x6" photo paper. Those for the enclosure...

... and those for the Drum Switch.

Then they are glued onto the box.

This looks really nice already (remember: the warped acrylics will be replaced!).

I am planning to use the Drum Switch to actually turn on/off the while time circuits, so I need to add some functional switches. For this purpose I am adding two micro switches which are closed by a lever in the Drum Switch.

In this configuration, my Drum Switch is not an on/off switch. It is only pressing two momentary push buttons (the micro switches). The on/off effect is later done in software.

I did say that I am building everything from scratch: Here is the handle for the switch. (The ends of the switch are not angled like the ones on the original battery terminal cleaner. I did not know how to achieve this with my wood-tools.)

 And the lever can be seen here in contact with one of the micro switches.

The Drum Switch gets the original "Dayton" sticker.

Inside the TFC switch is an Arduino Pro Mini which is reading the switches and operating the lamps. Via serial connection this Arduino is communicating with the Arduinos in the other components of the Time Machine. 

After another acrylics plate was bent for the Drum Switch (this time successfully!), the TFC Switch is complete. This is how it looks from all sides.

Related:

My other blog posts on BTTF-related props and pieces:

   - Building a Flux Capacitor

   - Building the Time Circuits

   - Building the Speedometer

  - Building the Analog Gauges

   - Building a Hoverboard and Charger
   - Building BTTF clocks
   - Building a BTTF Brick Stage (featuring the smallest Flux Capacitor)

Building Props for a Back-to-the-Future Time Machine - Part 4: The Analog Gauges

My other blog posts on BTTF props:
  Part 1: Building a Flux Capacitor
  Part 2: Building the Time Circuits
  Part 3: Building the Speedometer
  Part 5: Building the TFC Switch

After building the Flux Capacitor, the Time Circuits, and the speedometer, the next logical thing were the Analog Gauges. That triangular device that fits the glove compartment on the passenger side with those three beautiful old analog gauges and the red light which signals when you are running out of plutonium.

Some Time Machine builders are really trying to get the original old analog gauges like those used in the movie prop. But this would be too expensive, and not an option for me. I decided to buy three inexpensive Voltmeters and an illuminated red push button switch, and do the rest with 3/16" plywood and a laser cutter.

I disassembled the voltmeters and the push button switch. For the push button switch, I printed he word "EMPTY" (in Eurostile Bold font).

I designed the labels for the gauges in the open-source software scribus, for printing as 4" x 6" glossy photos. Here are the source images...

... and these are the printed photos.

The voltmeters are glued to the wood, and the labels are inserted.

The combined unit is then glued to the front plate.

Small holes are drilled for mounting the LEDs (5mm straw hat LEDs, which have a wider light cone).

The LED wires are bent so that the LEDs are facing upwards.

And the LEDs are glued onto the panels.

The electronics, based on a Arduino pro mini (ATmega 168, 16MHz, 5V), is assembled on a small PCB.

Everything is painted and the acrylic front pieces are inserted and held by additional wooden pieces.

Since my version is not mounted in the DeLorean's glove compartment, I need a full enclosure. 

And that's it. Here is the final unit.

And here, again, when the front panel LEDs are illuminating the gauges.

This unit does not have a sound player. But this piece is connected to the Time Circuits module and the two are communication via a serial connection. After turning on the Time Circuits, after three seconds, it send a signal to the Analog Gauges which then turn on. At that point the Time Circuit module is playing the "turn-analog-gauges-on" sound. 

Related:

My other blog posts on BTTF-related props and pieces:

   - Building a Flux Capacitor

   - Building the Time Circuits

   - Building the Speedometer

   - Building the TFC Switch

   - Building a Hoverboard and Charger
   - Building BTTF clocks
   - Building a BTTF Brick Stage (featuring the smallest Flux Capacitor)