This page is part of my Model Remodel series of articles.

DISCLAIMER: If you choose to attempt any of these modifications, you assume all risks thereof. I just wanted to share my experiences here. Neither Fanhome, nor myself, are responsible for any damages that may occur.

Finishing the Saucer Wiring

Now that most of the electronics have been attached to my custom Saucer Mounts, we can create the last of the wiring harness that will power and control the functions of the Saucer section!

Wiring Diagram

To help others understand how I am wiring my Saucer, I created this wiring diagram. You can click on this image for a larger version:

At the Bench (before we need the Saucer)

MOSFET Board

I prepared my MOSFET board by soldering Trigger/PWM (red) and Ground (black) wires to it using a length of 26AWG 2-wire cable:

This board was then secured to the right Saucer Mount with two (2) 2×4 mm plastic-thread screws I had left over from a previous partwork:

Voltage Dividers

Both the HC-05 Bluetooth Module and the DFPlayer Mini are limited to a 3.3V input signal on their RX pins. As I have mentioned before, we can lower the 5V output of the Arduino IO pins to 3.3V using a voltage divider. To create them, I first twisted the leads of a 1KΩ and a 2KΩ resistor together:

Next, I twisted the stripped end of a short wire around this connection:

To ensure a solid connection, these three wires were then soldered together:

I cut off any excess wire after the solder joint and separated the two resistors as shown. Here is how we will connect this voltage divider:

To prevent any shorts, I folded the solder joint over and secured the joint with heat-shrink tubing:

We need two of these voltage dividers, so I created another one using a purple wire for the DFPlayer. The open end of the 1KΩ resistors can be trimmed shorter as they only need to attach to the Arduino. However, the open ends of the 2KΩ resistors should be left long as they will be connected together and grounded later on:

HC-05 Connections

To make connections to the HC-05 (and the DFPlayer) easier, I used sections of 2.54 mm Female Pin Header. For example, I cut a section of header 6-pins wide so it could fit on all six pins of the HC-05. I then removed the two outer pins as we will not use them. Next, I soldered a length of 26AWG 2-wire cable to the pins on the header that match the appropriate VCC and Ground pins of the HC-05.

TIP: I recommend using heat-shrink tubing to isolate and insulate connections where possible:

I soldered a short length of blue wire to the TXD pin of the HC-05 header and connected the other end to DIGITAL pin 11 of the Arduino. Then, I soldered the wire of our first voltage divider to the RXD pin of the HC-05 header and connected the 1KΩ resistor to DIGITAL pin 12.

TIP: Before connecting wires to the Arduino, I recommend ‘tinning’ the ends of any stripped wires. This involves adding a little solder along the exposed metal strands (after stripping the wire) to hold them all together.

DFPlayer Mini Connections

The pinout of the DFplayer Mini is shown below. Remember, I mounted my DFPlayer upside down, so keep that in mind when making these connections:

Using a pair of pre-wired JST PH 2-pin male plugs, I cut the wires shorter to reduce extra wire laying around inside my Saucer. These wired plugs will allow us to quickly connect/disconnect the Speakers:

Using a new 8-pin wide section of female pin headers, I soldered both ground wires of the 2-pin plugs to this second pin from the end:

Using another 8-pin wide female pin header, the positive leads of these 2-pin plugs were soldered to the SPK_1 and SPK_2 pins. I also soldered a length of 26AWG 2-wire cable to the VCC and GND pins of this second header. Finally, I soldered the purple wire of our second voltage divider to the RX pin and a short length of white wire to the TX pin.

From left to right in this photograph, the second 8-pin header was wired as follows:

• VCC = red wire of the 26AWG 2-wire cable (power)
• RX = purple wire of our second voltage divider
• TX = white wire towards Arduino DIGITAL pin 3
• The middle two pins are not needed
• SPK_1 = red wire of one of the two 2-pin plugs towards the Speakers
• GND = black wire of the 26AWG 2-wire cable (power)
• SPK_2 = red wire of the other two 2-pin plug towards the Speakers

These two 8-pin headers were then attached to the DFPlayer Mini as shown. I also temporarily connected the nearby Speaker to verify the wiring would reach OK:

I connected the other Speaker as well to make sure its wiring would also reach OK:

At the Arduino, I connected the 1KΩ resistor of the DFPlayer RX voltage divider to DIGITAL pin 2 and the white wire from DFPlayer TX pin to DIGITAL pin 3. I also connected the open ends of both 2KΩ voltage divider resistors together and grounded them (arrow below):

5VDC Power Connections

I connected another length of 26AWG 2-wire cable to the 5V and GND pins of the Arduino to provide power to it:

Then, I disconnected all of the component wiring so far and laid it out on my work surface. I brought all of the positive (+) red power wires together (from the Arduino, HC-05, and DFPlayer) and wrapped them to the positive wire end of a 5.5mm male barrel plug connector. The same was done with all of the negative (-) black wires (from the Arduino, HC-05, DFPlayer, as well as the Ground wire from the MOSFET trigger cable). This barrel plug wire is the opposite end of the matching power connector I already installed into the Battle Section Neck:

These were all soldered together and connected to the VIN+ (red wire) and VIN- (black wire) terminals of the MOSFET. Since the MOSFET drives the LED Strip for the Windows, I wanted it to have priority access to the available current from the thicker 18AWG wire of this main power connector. Because this point is where the main power will feed into our Saucer electronics, ensure these two connections are well insulated from each other (and anything else):

This completed the wiring harness for my Saucer electronics:

As I began to re-install the wiring harness to the electronics, I secured the MOSFET board back into place:

The pin headers were re-connected to the HC-05 and DFPlayer, and the Speaker plugs routed towards the ‘front’ (away from the MOSFET):

Finally, the TX/RX wires for the HC-05 and DFPlayer were reconnected and the red Trigger/PWM wire from the MOSFET was attached to DIGITAL pin 9 (arrow below):

USB Cable Connection

This cable is entirely optional, but I thought it might be useful to be able to reprogram the Arduino even after it is closed up inside the completed Saucer. As I know we will have two removable magnetic panels on the bottom of the Saucer that are meant to allow access to the battery boxes, I decided to add a short USB Type-B Extension Cable to the Arduino’s USB port:

I popped this extension cable into the USB port of my Arduino. It will be held in place by the nearby Speaker once installed. Hopefully, I will be able to access the end of this cable through the battery box opening later on!

Into the Saucer

Mounting the Electronics

I secured my custom Saucer Mounts into the Saucer using the original PCB mounting points and FM screws. The slots I added to the mounts worked out great by allowing for some adjustability to make sure the holes all line up correctly:

LED Strip Connection

The 12″ length of cable I left attached to the LED Strip was shortened, stripped, and attached to the OUT+ and OUT- terminals of the MOSFET board. I ran this cable through the open space at the unused middle pins of the far DFPlayer pin header so it would fit nicer:

Lighting Ground Connections

I connected the two negative (-) Ground bundles from the Saucer Lights to these two GND terminals of the Arduino:

Lighting Power Connections

The positive (+) cables from the various Saucer Lights were then connected to the Arduino, as shown:

• Pin 4 = Forward/Side Formation Lights
• Pin 7 = Bridge Nav Beacon Light
• Pin 8 = Impulse Engine Lights
• Pin 10 = Rear Formation Lights

Speakers

Finally, I secured the Speakers to the Custom Mounts using spare 2×4 plastic-threaded screws and connected them to the DFPlayer:

You can see here how this left Speaker keeps the USB Extension Cable from falling out:

Main Umbilical Power Cable

I ran the barrel plug Power Cable under the inner LED Strips and out towards where it will later connect to the Battle Section Neck:

That’s it! My Saucer section is now wired and ready to go! Here is what it all looks like from above:

Reflective Tape

Finally, to help maximize the effectiveness of the LED Strip, I cut pieces of shiny aluminum tape and attached them to the inside surface of the various exposed U2-xx Deck Panels. This should reflect light inside the saucer and help brighten up the Windows in both the upper and lower hull surfaces:

I also placed strips of this tape along the inner surfaces of the shorter Skeletal Supports:

Next Section

LOWER SAUCER – Modifying the Lower Saucer panels (Coming Soon)