Category Archives: Electronic

Projects that involve some type of electronics hardware.

Cheap, Simple Hyperdrive Lights for the Lego Millennium Falcon

Kaiden finally received his long-awaited Lego Star Wars Millennium Falcon from Santa. By the next day, all 1,254 pieces were assembled. Pretty good for a 5 year old who stopped to play while he was building.

As we flew the ship around the living room one evening, the blue Christmas tree lights gave me the idea to install some LEDs in the back of the Falcon to light up the hyperdrive. I remembered that I had some small, bright blue LEDs left over from a robot project and we got straight to work. Below is a walk-through of what we did as well as a few alternative options to consider if you plan to do this yourself.

Hyperdrive Lights

Stuff You Need

You may not need all of these tools and parts, but here’s what we used:


  • Wire cutterTools
  • Wire stripper (optional, but I love my wire stripper)
  • Crimping tool
  • Soldering iron and solder (you can get cheaper ones, I’ve had this Weller for many years)
  • Helping hands (mini-vise to hold parts while soldering)
  • Rotary tool (if you need to modify the Lego parts, my 20 year old Dremel still works like a charm)


  • 4×LEDs (bright blue or white)Parts
  • 4×2032 3V coin cell batteries
  • momentary push-button switch (or a toggle switch if your 5 year old always remember to turn it off… yeah, right.)
  • 6×2-pin header connectors (see picture)
  • 1×4-pin header connector
  • 4×male header pins
  • 12×female header pins

Notes on header connectors and pins:

  • You could do without the headers and pins and crimping and just solder wires and LEDs which would be much quicker. I like to build things so that I can re-use the parts later when (not if) my son finds something more interesting. My Railroad Crossing Signal is a good example and we’ll be leveraging the sound chip from that for some sound effects in the Falcon later!
  • You can buy 100 of each type of pin quickly with Amazon prime (male, female), spend 10× less on eBay (male, female), or buy a smaller quantities of connectors and pins at places like Futurlec. If you have a local electronics store, like Jameco or Anchor, please support them!)


  • I modified a couple of parts, but there a million options for securing buttons, LEDs, and batteries since it’s Lego!
Lego Parts
Parts to cut and drill
Battery box

How We Did It

  1. Decide on a layout. Choose whether you want the LEDs in parallel or in series. This determines what your battery pack looks like as well as whether the entire things stops working if one LED bites the dust (series). The blue LEDs have a typical forward voltage of 3.5V so to keep everything simple, I used 4 3V coin cell batteries in series with 4 LEDs. So the circuit is very simple.
    Thruster Lights schematic 1 You also need to decide how to connect the various components. Based on the ease of making a small, square battery box and the use of header connectors which let us easily replace individual LEDs, we went with the serial option. If you solder parts instead of using connectors, consider how you’ll make repairs. This is also a good time to disassemble the back of the ship and identify where everything will go.
    Falcon Hyperdrive
  2. Build the battery box. Kaiden designed the box out of Lego parts and we adjusted the height to fit 4 coin cell batteries with just a little space remaining. The parts shown include decorative pieces at the top of the picture.
    Our battery box parts
    Our battery box parts

    Click here for a video on assembling the battery box:

    Battery box video

    To attach leads to the battery, I just used the same 22 gauge wire, stripped off extra insulation, and created my own springs. Once the top panel of the battery box was closed, it created a tight connection that has not come loose since.
    Battery Box connector 1
    Battery Box connector 2
    Battery Box connector 3
    Battery Box connector 4
    Battery Box connector 5

  3. Crimp or solder the wiring. Measure wire lengths based on your decisions in the first step. You might consider soldering components or using fewer connectors, for example, on the battery pack and switch. The reason I put connectors on those parts is because I thought I might later add a microcontroller to flash the lights. I also have quite a few of these connectors in my parts box. Here’s my schematic with the connectors shown.
    Thruster Lights schematic 2Here is good video tutorial on crimping if you’ve never done it before. The video covers more than just one type of connector and pin and shows how easy it really is.
  4. Prepare the button. I used a single 2×2 brick to house a push button that could be easily attached to the underside of the ship and that worked out nicely. Choose a brick to match your button or switch or find another place to mount it. I had to drill out the middle of the brick a little so that the button would be flush with the edge. I also drilled a small hole in the side for the wire connecting the switch to the rest of the circuit. The momentary push button also ensures that none of us will forget to turn off the lights when we are docked at the space port at dinner time.
    Push button 0
    Cut or drill out some of the block so the switch fits inside and also drill a small hole for your wires to go through.

    Before and after cutting and drilling
    Before and after cutting and drilling

    Insert the wires and solder them to the button.
    Push button 1
    Attach the button to the ramp.
    Push button 2
    Push button 3

  5. Install the LEDs. We needed another “custom” Lego part to hold the 2 LEDs in the middle in place. It may be an actual Lego part, but we didn’t have one so I found a Technics piece that I could just cut in half.
    Lego Parts Modified
    These pieces are used to hold the 2 LEDs in the middle in place like this:
    LED holder
    A little more disassembling might be in order…
    Installation 5
    The 3mm LEDs fit nicely inside the blue tubes and here is how we assembled these.
    LED install 1
    Installation 3
    Installation 4
    We ended up having wires strewn about the ship, but if I recall, the Falcon was a bit messy inside anyway so we won’t waste time trying to hide any wires.
    Installation 2

    Final test before reassembly
    Final test before reassembly

I may change the configuration later when we add more lights, but for now, it’s a nice, simple and cheap setup. The next logical addition is to add forward flood lights so stay tuned.


Control Panel with Buttons, Switches, and Lights part 2

Adding the lights and switches to the Master control panel.

First thing on the agenda, especially since Phase 1 of the Master Control Panel stretched out so long, was a second trip to the flea market for more buttons! We also scored a very cool “Video Commander” control station with a dozen buttons, a joystick, and a couple of rotary control knobs. That’s put aside for a future project since we’re moving right along…

All the buttons and a couple of the toggle switches required little more than the right sized drill bit, which Kaiden is now an expert at selecting. The rectangular toggle switches required filing and sanding and more effort than they seemed to be worth, but I quickly forgot about that when I saw my boy’s smile at the addition of the LEDs!

A few years ago, also at the Electronics Flea Market, I spent $10 to get a 30 drawer storage cabinet. The elderly gentlemen who sold it to me said I could keep any parts in side and he offered me a deal on a second cabinet, but I declined since it had a few cracked plastic drawers. Well, when I put the cabinet in the car and took a better look inside the drawers, I realized the value of the deal I had gotten. That cabinet was full of LEDs, sockets, connectors, and some parts which I have yet to identify. In total, it was worth far more than $10 and by the time I raced back, the second cabinet was sold. Anyway, we used several of the LEDs in this project.

The key switch is something I pulled off a broken cash register many years ago so I hope it works! I have several keys to go with it and they allow the switch to turn either 2 clicks, 3 clicks, or 4 clicks. We decided that Mom would get the Level 2 key, I would get the Level 3 key, and Kaiden would get the Master Level 4 key. So Kaiden said to me, “Dad, if you ever need to use a function on level 4, but I’m at school, you’ll have to wait until I come back to turn it on for you.” I really hope that switch works and probably should have tested it before we installed it. We’ll find out soon enough.

When we first installed the key switch, it didn’t look that great. So I took an old lid and some tin snips and made a small metal plate to cover up the hole. Kaiden helped with the tin snips, but gave up after a while since it took so long to make any progress.

installing buttons and switches
Installing buttons and switches
key switch and tin snips
Tin snips at work to fix key switch

Now, it’s really starting to look like a Master Control Panel!

wrapping up phase 2
Phase 2 wrapping up!

We’re thinking about putting in a speaker in the lower center instead of hiding it inside and deciding what top secret instructions or codes to put in the blank space in the middle right.

The project list keeps getting longer so we’ll see how soon we can get to Phase 3.

Build A Custom Control Panel with Buttons, Switches, and Lights

It’s taken me a couple of years to get around to this project, but it still seems to be a hit today.

The Plan

Being cautious about unfinished projects (and we have a list of those already), Kaiden and I decided to build the Master Control Panel in phases.

  1. Build the main box
  2. Add hardware (buttons, switches, and lights)
  3. Add electronics and code so the buttons, switches, and lights all do something

Stuff You Need

  • A wooden box or wood to build a box (top, bottom, and sides)
  • If building from scratch, 4 short pieces of square dowel help join and support the box
  • 8 wood screws to hold the top and bottom panels in place (removable panels are necessary for further upgrades)
  • 4 rubber feet for the bottom of the box (so Mom will allow it on the kitchen table)
  • Wood saw
  • Drill
  • Screwdriver
  • Ruler or tape measure
  • Pencil
  • Small T-square
  • Wood glue
  • Small clamps
  • Buttons and switches and lights – yes, this is phase two, but start collecting now if you don’t have enough!

How To Make It

Phase 1, building the box, took longer than expected since a) I have a wood saw and an old-school wood sanding block and b) Kaiden was in charge of the layout and he helped to sand the pieces. We also had limited time between work and dinner, but since we had to let glue dry in between, it worked out well.

I used an extra piece of board I had left over from a kitchen-shelf project and Kaiden selected the wood screws. We measured, I cut, we sanded, I glued, we clamped, and we waited. A trip to the San Jose Electronics Flea Market scored some awesome buttons, most of which were $1. Kaiden was in dreamland just trying to decide what color buttons he wanted to use.

control panel boards
Boards cut, sanded, and ready for assembly
buttons and switches
Buttons and switches; flea market gold!

Clamping and gluing the base. I got overzealous with the clamps at one point, tramadol trying to get done faster, but it all worked out.

board assembly
Gluing and clamping
clamping boards
Note: glue 2 pieces at a time, not 3

Phase 1 complete and Kaiden’s first pass at the layout for Phase 2.

control panel base
Almost ready for the hardware
designing the layout
Kaiden’s first pass at the layout

Stuff We Learned

While I worked on the box, Kaiden spent time playing with the switches (and planning more projects that could benefit from the addition of a blue switch or two). He got to learn about normally open and normally closed switches (at least in theory) as well as momentary push-buttons vs. toggle switches. He’s spent time at my workbench in the past learning about tilt switches and rotary switches and he’s used momentary and slide switches in his Snap Circuits Jr. kit so there wasn’t much to cover. Also, when the switches are hooked up to the lights and speaker, there will be a better appreciation for how they function.

On a side note, I would highly recommend Snap Circuits sets for beginning electronics. Because Kaiden is advanced for his age in some areas, I personally always ignore the very conservative recommended age ratings on most products. With proper supervision and instruction, almost any child can enjoy and learn from these sets well before the 8 year old rating. I’ll write more about Snap Circuits later.

Kaiden got a chance to practice his wood working skills, including sanding and drilling. I drilled the screw holes for the box, but gave him his own small cordless driver with a few drill bits to practice on a scrap piece of wood. The biggest lesson was on ways to extract a stuck drill bit without getting Dad to do it every time!

Whew! That too longer than planned, but so far, we’re pleased with the progress. Stay tuned for Master Control Panel Phase 2.

Make a Railroad Crossing Signal with Lights, Sound, and Action

My son likes rail road crossings so for his third birthday, I decided to build one. I made it from scratch with supplies from a crafts store and some electronics. There is a small speaker in the bell at the top, a pair of jumbo LEDs for lights and a servo motor to move the bar.

The parts were all quite cheap, except for the sound chip which I selected for convenience since I was running short on time. In the next version (if I ever get around to it), I’ll replace the sound chip and I’ll design a printed circuit board. I may also lower the base so it can work with actual train sets. We use the ramped tracks from his wooden train set to go over the back of the base or he just plays with the signal on its own.

For his actual birthday anti anxiety party, we rented a caboose and took a ride with friends through Niles Canyon and I baked and iced a RRXing cake. The crossing signal topped off the busy day and he loved it, but planning the party, making the cake and icing from scratch, and building the railroad signal was an insane amount of work to do in my spare time.

I don’t think I’ll post a formal set of instructions, but here are some details…

railroad crossing signal electronics
Testing the electronics
railroad crossing signal parts
Wood parts: box, discs, balsa, dowel
railroad crossing bell
Speaker inside hollowed out wooden disc
railroad crossing lights
Jumbo straw, jumbo LEDs and black paint
railroad crossing signal lights and bell
Mounting the lights and bell
Final assembly the night before the party
Final assembly the night before the party

Oh, and here’s the tasty part…

railroad crossing signal cake
The letters are chocolate cookies :)