How I Spent My Summer of 2014
by Julius von Brunk
Built originally for Star Wars Day 2014, I present to you a project that I’ve been constantly revising and making additions to since April until August 2014 — into a near-final refined form as you see now. This is a life-size replica of Han Solo’s iconic weapon à la Star Wars, recreated with LEGO bricks, and fully rigged to light up and play sound effects with triggered! This particular model — a prototype with crude electronics — may seem rough around the edges, and even uses a lot of improvised jury-rigging in its functionality, based on what LEGO pieces and electronics I had available. Building this project was a challenge to say the least, and had more electronic malfunctions than you can shake a stick at! I ran into multiple issues with the Arduino code, the problems with the breadboard parts experiments, wiring the circuit, and of course designing the physical LEGO portion itself. In making this creation, I’ve taught myself how to program with Arduino, as well as I’ve improved my electronics savvy so that subsequent electronic LEGO models of mine will be more sophisticated.
Microcontroller: ATmega328P-PU, coded with an Arduino Uno
Power: 2 AAA batteries (3 volts DC)
Production History
In March of 2014 I went to a Korean grocery store in my town in order to purchase a steam iron for ironing out the wrinkles in my cloth photography backdrops. While waiting in the checkout line, my mind began to wander as I stared at the packaging of the iron and randomly thought back to a certain moment of my early teen years. When I was 12 years old, a coveted object I wanted more than anything at the time was a toy replica of Han Solo’s iconic DL-44 Blaster pistol as seen in the Star Wars franchise. The particular toy I wanted was bright orange, and played sound effects when the trigger was pulled. After I had enough paper route money to buy one, I tested it out at the store but was devastated to find out the muzzle didn’t light up, as I falsely assumed did. It only played sounds, but flashed no lights. The other DL-44 Blaster replicas I saw around that time were either for laser tag (with no lights), or were mere squirt guns. Back in the reality of 2014, I walked out of the grocery store and thought to myself: “I kind of wish I had a replica DL-44 Blaster that actually does light up — but wait, why can’t I build a LEGO one!?”
Throughout March-April 2014, I conceptualized the inner functions of making a LEGO replica of the pistol. First I did several experiments with Technic engineering to make mockups for the trigger functionality, as well as the gun’s firing pin. Initially I assumed I could use the reciprocating spring mechanism from my giant NES controller‘s buttons, however this was implausible, which meant I soon came up with a system using small rubber bands. LEGO produces small rubber bands for certain sets, but since they’re usually hard to find and only available in limited sets, I figured those tiny rubber bands for hair could simply do the trick. I bought a pack of hundreds of small black rubber bands from Rite Aid, and rigged up a mockup with pulleys, pins, and and a sliding track.
When pulling the trigger, the gun’s firing pin slides down a track with smooth LEGO tiles and strikes a momentary pushbutton held in the front of the gun. After I built the initial mockup of the firing mechanism, I tested it by pulling the trigger dozens of times to gauge its durability. At first the rubber bands snapped off due to high tension, which meant I had to slightly rebuild it to have the rubber bands closer than before, which made the mechanism a bit looser, but also prevented the firing pin from snapping off. Once I figured out this major obstacle, the next issue was being able to illuminate the muzzle flash. For the barrel and muzzle, I ultimately used a series of round bricks with Technic pulleys, held together with a hollow pneumatic Technic hose in the middle keeping the barrel in place. The hollow hose has two wires snaked through it, which are soldered to the anode and cathode of a high-power LED. The orange tip of the gun uses transparent orange bricks and Technic pulleys, and held down with Technic pins.
Keeping the momentary pushbutton in place was pretty straightforward, as I used the same sort rigging in my illuminated mosaic Legend of Zelda portrait, which had a DC adapter female terminal held into place snug with LEGO pieces. The next phase was making an electronics box for the lights, sound, and battery, which was difficult to say the least. In fact, the electronics portion completely dwarfed the engineering and design issues. Now, as mentioned previously, this project was specifically designed to be released on Star Wars Day (May 4th) 2014, and by this point it was around early April: time was running out, and I had only a couple of weeks to figure out how to generate lights and sounds, despite my then-inferior knowledge of electronics. Trying to figure out how to create the sound box for this project, I scoured the internet for help and stumbled upon this tutorial for making prop Star Wars blasters with a Radio Shack sound recorder, plus some minor hack/mod skills. That particular tutorial is what I pretty much followed when creating the first circuit for my blaster; as you know, I made two major revisions to my gun’s circuit — the Mk.I and Mk.II — the latter being the final one shown in this article. Prior to making the Mk.II design — which had a custom Arduino circuit and sophisticated creation — the Mk.I was very crude, faulty, and merely consisted of a small Radio Shack sound recorder rigged in parallel with a timer circuit I built. The Radio Shack sound module was a unit with a small chip, a speaker, and record/playback buttons for playing tinny sounds; think of the same low-quality like a YakBack. However, they’re small, cheap modules and used mainly for educational purposes rather than as legitimate sound recorders. Basically, they were obviously marketed for the sole purpose of guys like me to hack them apart, instead of using them for something which requires high quality.
In the original tutorial, the author removed the buttons for the playback and was able to trace the contacts to have it controlled by his own pushbutton. I did likewise, and did a very crude technique to wire the sound record function into a microphone jack and send the sound effect of a DL-44 Blaster from my computer directly into the module. I actually used a sound effect of Dash Rendar’s pistol from the N64 game “Star Wars: Shadows of the Empire!” I then spent the next week or so making modifications and revisions to the little circuit to have it controlled by an external pushbutton, but unfortunately due to my shoddy soldering, I fried some of the connections thus rendering the whole recording unit obsolete. Well, that was $13 wasted. The next day I went to the Radio Shack in Great Neck, NY and purchased yet another recording module, and promised this time I won’t screw it up.
Unfortunately, the particular model of the small Radio Shack sound recorders which were made at the time of this project were designed to be difficult to hack apart. Essentially, earlier models had more of their circuits exposed which could allow easy modifications for removing/adding components and solder, whereas these newer ones had most of the vital components covered with a blob of black resin. Nonetheless, I managed to make some modifications to this new sound module. The original speaker that came with it was a small, green 10 Ohm .5 Watt speaker with a diameter of about 2 inches — too big to fit into the body of the blaster. I had limited space with cramming the sound box and speaker (and hopefully battery) into the small square magazine on the front of pistol in front of the trigger, below the barrel. Originally I intended to cram all necessary electronic parts solely into the magazine, but later when I ran out space, I had to rebuild the gun to have a hollow handle for storing the battery.
As time ran out, it was the Friday of weekend of Star Wars Day, and I had less than two days to finish this by the deadline! I ran to Radio Shack and picked up several varieties of resistors, capacitors, jump wires, and a breadboard for making a 555 IC single-shot timer LED. What that means in layman’s terms: a circuit for making an LED turn on for just a few seconds after a button is tapped, rather than keeping the LED on only as long as the button is held down. Basically, an LED that remains lit for about two seconds after a button is pressed, like a gun’s trigger. Otherwise, simply having an LED rigged up to a switch would merely only illuminate for the duration of the button’s pressing; in that case, tapping it for just a split second would only have it lit up for a split second. Using a series of resistors, capacitors, and a 555 timer, I constructed a breadboard circuit for keeping an LED lit for about an entire second after the button is released, to accurately mimic the flash of a gun. Once the circuit was functional, I used the modified Radio Shack sound box to be wired in parallel with the 555 timer circuit. Tracing the contacts of the sound module, I found out which two points of the circuit control the V+ and ground, thus I soldered two jump wires to those spots and connected them to the respective points of the 555 circuit.
Next came the point where I followed my breadboard design onto an actual circuit. Since my soldering skills were still crude at that point, I spent all Saturday afternoon building the small homemade circuit with a handful of components. For with limited space inside the gun’s magazine, I needed a tiny but powerful speaker; the Radio Shack speaker originally included with the sound box was way too big. I dug through a box of junk and broken electronics from my old job at a company called Tzumi, which specialized in cheap, novelty electronics from China. Low and behold, I found a tiny 8 Ohm .25 Watt speaker about the same diameter of a quarter: it was the speaker from a novelty USB Santa Claus statue that played music and danced around! A few years previously when doing experiments with electronics for my Fireflower Airship, I broke the Santa statue apart to use some of the pieces — and the speaker was still intact and functional. Once the new homemade circuit was complete and wired into the modified sound box (with its new speaker), I tested it several times with various battery sizes/types to find out what’s necessary for powering this gun; this was how I learned about voltage and amperage variables in battery types. I also noticed that the sound quality with the tiny 8 Ohm speaker was noticeably tinnier and quieter than the original Radio Shack one; the DL-44 blaster sound effect sounded almost like a screeching CHEEE CHEEEE CHEEE noise than a laser blast.
I’m not going to deny that I poorly planned out how I’d power this gun, thus with my then-minuscule knowledge of batteries and power, I falsely assumed I could power this whole thing with tiny coin or button cells, hence I built limited space in the gun’s magazine with the intention of housing tiny batteries. As you can tell, I required something larger with significantly more kick; the Radio Shack sound box needed a 9V battery, but I also tested and figured out I could do the trick with four AAA batteries. But alas, there was no more room in the gun to contain the batteries — as the magazine was crammed full with the sound box, speaker, and 555 timer LED circuit. Now it was late Saturday night right before midnight, and I ran into a major dilemma with rebuilding the LEGO portion of the gun. Feeling despair and doubt, I did my best to figure out what I could possibly do to keep the batteries in the gun. I realized I could rebuild the gun’s handle to be hollow for housing batteries, but this would require wires to be connected from the sound box to the handle while remaining concealed. Faced with both engineering and electronics obstacles — all in all with time running out — I took a break to go to Rite Aid for energy drinks and beef jerky.
It must have been around 1 or 2 AM, and I was at Rite Aid purchasing a can of sugar-free Rockstar and a big bag of teriyaki beef jerky fuel this all-nighter. I stayed up all night well into the small hours trying to come up with a method of powering this thing with adequate battery power as well as containing them in a revised portion of the gun. I was streaming reruns of the U.S. version of Whose Line is it Anyway? as I tinkered with both electronics and LEGO. Probably around 4 AM (when I got to that episode with Colin Mochrie dancing the Asteroid Boogaloo) I tried to create a battery pack by taping four AAA batteries together in series, however I lacked the necessary parts for secure connectors — thus I had to just use a 9V battery, as I had a few 9V wire connectors. Unfortunately, the newly-hollowed out gun handle was still too small for keeping the 9V battery — hence I had to modify it yet again to have enough clearance for the battery. At this point it was probably around 7 AM, and I was falling asleep: I decided to go to bed, wake up, and rush to finish the project and subsequent photo shoot later on Sunday afternoon.
I think I woke up tired and lethargic around 1 or 2 PM on Sunday, with the whole day devoted to making the final revisions of both electronics and LEGO engineering. At this point it was already Star Wars Day, and I already missed the chance of releasing the polished project on social media for May 4th. The gun’s necessary electronics and design weren’t even complete, let alone photographed and recorded on video for the big release, yet I decided to continue working on it throughout Sunday afternoon. I managed to fix the gun’s handle in order to have room for a 9V battery, and to conceal the wires, I removed the gun’s trigger guard and replaced it with a hollow ribbed Technic hose — which was connected from a Technic brick in the gun’s magazine and connected on the other side to the gun’s handle via Technic plates. I snaked the 9V connector wire through the handle to the magazine, then wrapped the wires around the contact points of the 555 timer circuit (crude and insecure, but connected). The 9V battery was now connected and housed within the gun’s handle. Thunderbirds are go!
Once I overcame these major obstacles, it was around Sunday evening and in preparation for the photo/video shoot — but, as Murphy’s Law dictates, another problem occurred: the LED on the front of the muzzle burned out — possibly due to being used on and off with varying battery types/sizes, thus damaging it. I had to carefully remove the LED from the muzzle, but in doing so, I tore off the super-thin jumper wires that were snaked through the barrel attached to the circuit. The inside of the barrel is a thin Technic hose that barely has enough clearance for one 22 AWG wire — let alone two — hence through the hose were two strings of extremely thin 30 AWG wrap wire. Because the wires were so thin, slightly tugging on them (as in to remove the LED) tore them loose from the circuit. Feeling extremely frustrated, I spent the next hour or so constantly trying to reattach an LED as well as two new strands of 30 AWG wire. At this point I thought there would no way in hell I could finish this thing any time soon and shoot the photos/video before midnight. I was about to call quits, but decided to keep trying to carefully repair the LED and wires — which I eventually did. Now it was around 9 PM: time for the photo and video shoot.
Video demonstration of the Mk.I model. Notice the tinny, brief “CHEEE CHEEE CHEEE” sound:
The images below are the final, edited photos of the Mk.I after its completion on May 4th, 2014. The general LEGO structure is virtually identical to the Mk.II, except for a few things: the handle in this version is a bit fatter in order to house the 9V battery (the Mk.II only uses two AAAs). Also, the gun’s magazine — where the circuit is stored — opens on via a door on the port side, whereas the Mk.II has the door removed and simply has the entire port side’s face snap on and off.
The photo shoot and subsequent editing session in Photoshop lasted until around 10 PM. The actual video shoot lasted a few mere minutes, but I ran into a ton of unnecessary issues in Adobe Premiere when editing the raw footage — thus the final, polished video demonstration wasn’t successfully exported until a little bit after midnight on May 5th, 2014. To avoid disappointing my fans, I posted the photos of the gun on Instagram immediately upon editing, so that I could make the deadline, but unfortunately I didn’t post the video until the next morning. Due to the lukewarm reception of the Instagram post versus the buzz leading up to its creation, I didn’t really promote it much on social media — as quite frankly, I was disappointed with both the final version as well as the reaction. That being said, I didn’t post the demonstration video on YouTube neither — and instead decided to go back to the drawing board and rebuild the circuit to be more sophisticated. . . The Mk.II revision!
Mk.II Model Revisions
Throughout the remainder of the summer, I took a break from doing elaborate, epic LEGO creations and instead started doing simple vignette photography with my minifigures. In addition, I scoured the internet to study more about electronics and how to make significant improvements on the next circuit. As I increased my knowledge on electronic components, I tried to decide the best way to make a miniature circuit for both sound and light. I read a few tutorials online about using EEPROM chips to have sound data stored on them, but wasn’t able to figure out how to design the schematics. Then I found a few tutorials on Instructables for making custom props using ATtiny85 chips — notably this particular tutorial for making a homemade Sonic Screwdriver from Doctor Who.
This next task required usage of an Ardunio, and luckily I had an Arduino Uno model that I won in an Instructables contest just a few months prior. At this point in my experimentation, my knowledge of Arduino coding was very basic — as in, the most I could do was copy and paste a code, and connect it to the chip! The Sonic Screwdriver tutorial contains a code for playing a tiny sound clip of the Screwdriver buzzing whilst making an LED light up: I wanted to use this particular code, but modify it to have the LED stay on for a few seconds after the button had been pressed, and to play the entire clip of the blaster noise — rather than looping the buzzing sound. Unfortunately, I wasn’t able to write the code properly — in addition, I discovered the ATtiny85 didn’t have adequate memory space for keeping the blaster sound effect and the code. The blaster noise when compressed was about 16KB — exceeding the 8KB limit on the ATtiny85; this meant I needed a bigger chip, hence I started experimenting with Atmel’s larger model, the ATmega328 — which is also the exact chip used on the standard Arduino models.
The next few weeks consisted of doing hundreds of various experiments with codes and electronics components — only for failed results. I was gradually figuring out the ins-and-outs of writing Arduino code, yet my knowledge was still at a beginner level. My intended code was simple in theory, but difficult in execution:
- Tap a button to activate a sound effect stored in 8-bit data
- Simultaneously make an LED flash for 1-2 seconds
- Put circuit to sleep immediately after the cycle, to prevent battery draining
All three of these tasks combined required knowledge of how to control the device with external buttons, how to activate sound files stored on the chip, how to control LED output, and finally how to activate a standby function. For the sound portion, I found a basic Arduino open source code for playing small sound effects from the chip, after a sound file is converted to binary code and uploaded into the microcontroller. In this particular code, the sound effect plays once each time power is sent to the unit; I tinkered with dozens of button techniques and variables to have the sound activated by an external switch, which was of course ultimately successful. Onto the blinking LED portion: I merely used one of the preexisting standard codes for controlling an external LED — hence I incorporated the code to work simultaneously with the sound effect, so that it would blink throughout the duration of the blaster noise. Since the standard Arduino DC power is about 5.5 Volts with its voltage regulator, the output sound and lights were significantly more power on the Arduino unit compared to the actual breadboard prototype with my ATmega328. This meant I needed stronger speakers, but not too powerful as it would damage my microcontroller.
“. . . I accidentally built a radio!”
The little speakers I used in the first experiments (as well as the final project) were 8 Ohm .1 Watt — about the size of a quarter, purchased from Radio Shack at an unnecessary markup — and worst of all, only like one store near me sold them, and I needed several for my experiments in case I’d accidentally damage one when giving incorrect power levels. I had to frequently go back and forth to the Radio Shacks throughout Bayside, Great Neck, and Manhattan just to track down these damn things — all in all, the dumbfounded teenage store employees looked at me like I was speaking some kind of foreign language when asking for a model number from their website. “Huh? Resistor? Piezo transducer? Capacitor? I don’t know what that is. Can I interest you in a new Samsung Galaxy or a pair of Dr. Dre headphones!?” As much I hate delays and shipping costs, I realized it was better to purchase everything online from Digi-Key, JameCo, and eBay — since I knew specifically what I wanted. I then purchased several tiny speakers off Digi-Key, each of various sizes and values; some the size of a dime, some with 1 Watt of power — none of which were usable. Unfortunately, the little Radio Shack speakers were the best option, and would eventually be used in the revised Mk.II blaster.
The sound was still way too weak when experimented on the breadboard, as opposed to the super loudness on the Arduino. The next major dilemma spanned over a period of two weeks: trying to make the sound loud enough, without damaging parts by increasing power. Too much electricity? Fried resistors and hot parts. Not enough electricity? Quiet muffled of a blaster sound effect. This meant I either needed an external amplification device, or an acoustic sound modification (such as a paper cone to increase the output). I managed to find an LM386 amplification chip from Radio Shack, and spent a whole weekend making various configurations of it along with capacitors to increase the sound output — all with failed results. At some point around 4 AM on Sunday, I slapped together a configuration of wires and parts along with the LM386 on my ATmega328 breadboard, and suddenly began hearing voices. “That’s odd — I turned off my music during this experiment in order to hear the blaster sound effect. Perhaps it’s the neighbors downstairs talking?” The voices sounded muffled, as if from outside. Just then I put my ear close to the breadboard, and realized the voices were coming from the speaker. Apparently, my backwards configuration turned the amplifier chip into a radio receiver; one of the jump wires on the breadboard came loose, and while still connected to a random pin of the chip, it acted as an antenna. . . I accidentally built a radio!
Eventually I scrapped the LM386 and came up with the idea of using transistors, resistors, and diodes in the proper configuration. After another day of experimenting, I correctly solved how to amplify the sound loud enough without damaging the parts, by using precise resistor values in conjunction with a tiny transistor. With this obstacle now solved, the final task was programming the code to shut off the entire circuit when the cycle is complete, to avoid draining the battery. I was debating having a simple kill switch on the gun, however I wanted to keep the configuration simple by just having the gun’s trigger as the only button. This required scouring the internet for multiple tutorials on how to install a shut off command in the Arduino code. I found this particular article for having various levels of “shut off mode”, such as idle, power save, standby, and power down — the latter of the set wouldn’t shut off the microcontroller completely, but instead would only allow it to draw a tiny fraction of a percent of electrical power while connected to the battery. When incorporating this code into the master code, I added a call function to make a second LED blink in synch with the microcontroller being in full-power mode — almost like an “ON/OFF” indicator.
Although the Mk.I was rushed as I raced against the clock to release the project by Star Wars Day, this new revision was also racing against a deadline — the Instructables Toy Block Contest of 2014 — a contest which ended in mid-August. At this point in the experiments, it was around late July, and though I still needed more work done to complete this project, I was confident in releasing it and entering the contest before closure.
Baron von Brunk Shot First
With the deadline for the contest drawing near, I was putting my skills into overdrive in an attempt to complete the Mk.II revision. I was running back and forth to Radio Shack so frequently, that I was becoming a store regular for the Bayside and Great Neck locations; in retrospect, this was during the final days of the store’s lifespan anyway, hence I may have seriously been the only customer at either location. I kept damaging LEDs, resistors, and speakers during my numerous experiments, and also I’d buy random transistors and diodes in an attempt to fix any issues with sound/light output. For electrical power, in the early breadboard stages of the standalone ATmega328, I’d power it with three or four AAA batteries, but with the voltage regulator they were stepped down to 5.5 Volts DC. The battery source I planned on using for the final circuit in the gun itself was a makeshift pack of beefy 3 Volt coin cells that I scoured from the internet. These batteries were about as wide as a quarter, but as thick as a stack of four or five quarters — each one delivering 3 Volts, thus two of them linked together in series would deliver 6 Volts before being stopped down in the voltage regulator. Their amperage discharge was I believe 1,000 mAh, thus one little coin cell was had about the strength of two whole AAA batteries with a fraction of the size. At this stage in my electronics knowledge, I only knew of the voltage and milliamps per-hour — I knew nothing about maximum discharge rate, which is a crucial variable often neglected on most battery packaging.
I believe it was on a Friday night of the weekend right before the deadline for entries to the Instructables Toy Block Contest 2014, which was on Monday night at 11:59 PM pacific time. At this point in the construction, I had successfully written a functional Arduino code for making the light flash in synch with an audible sound effect when a button is tapped, with the chip shutting down after the series of tasks. I also successfully transferred the data onto my ATmega328-PU chip and ran numerous experiments on a breadboard. Now, Friday night’s major task was using my soldering iron and components to construct a homemade circuit based on my breadboard schematic. My soldering skills were a bit below intermediate at this point, but I was making improvements. I stayed up all night building the completed and functional mess of wires and contact points onto a single perforated prototype circuit board — after ruining two previous circuit boards by placing the components on the incorrect spots, using too much solder, or burning the electronics parts with incorrect solder techniques.
With the third and final chip completed at last, I tried to fit it inside the magazine of my gun — but alas, lacked the necessary room to keep it inside. I had to slightly adjust the design to have the circuit’s voltage regulator separate from the rest of the chip, and instead stored inside the battery compartment in the gun’s handle. With this design, the battery would be wired into the voltage regulator and capacitors, and the output power would run through two wires snaked through the gun’s trigger guard pipe and to the magazine with the central circuit.
Samuel Colt couldn’t have done a better job himself.
On Saturday afternoon, I assembled the gun and attempted to do the photo shoot. When putting the whole shebang together and taking some test shots with my camera, the gun’s circuit randomly stopped working. Sometimes I’d pull the trigger, and the LED would inadequately blink, and the sound would be choppy to the point of shutting off — it was as if the batteries randomly died on me. After attempting in vain to find out what the hell was causing the problem, I yanked out the coin cell battery pack and inserted a battery case of three AAAs. The circuits worked fine — and it appeared that the problem was that the two coin cells weren’t providing adequate power. Despite each one being 3 Volts and offering a whopping 1,000 mAh, they should have provided enough kick to power this — therefore I checked online to look up the batteries’ data sheet from the manufacturer. Unfortunately these batteries were of an obscure, uncommon brand typically not sold in the U.S. — in fact, I bought these from eBay from a sender in Thailand — in other words, these sure as hell weren’t common Duracells or Energizers. I found a data sheet of their type and information, and it was then I discovered a third variable in battery power: maximum discharge rate — the amount of charge a battery can draw at any given moment. Small batteries like button or coin cells typically have a tiny discharge rate of .10 to .20 milliamps — whereas a common AA battery can discharge an entire amp at once. In layman’s terms, my coin cells technically had the physical strength to power the gun’s circuit, but were only capable of sending a tiny fraction of that power. My only option was to use a whole battery rig based on stronger batteries — which couldn’t fit inside the gun (I needed four AAAs to get the 6 Volts).
I assumed perhaps if I attached a capacitor to the the point on the circuit where electricity goes into the voltage regulator, it could help draw more of a charge. This almost worked in execution: using large 200 uF capacitors prior to the voltage regulator actually caused the gun to function normally and smoothly. I squeezed the trigger dozens of times throughout the minute until the lights and sound started flickering again — and I noticed smoke coming off the coin cell battery pack. I peeled off the tape and saw acid leaking out: these damn things truly weren’t meant to have any significant discharge power — they were just slightly larger wristwatch batteries. I spent all Saturday night researching battery types and trying to figure out what I could do to substitute. As mentioned previously, there was barely any room in the gun’s handle, hence I could only fit two AAA batteries at the most, which would only get me 3 Volts DC. I tried to see if Radio Shack made any obscure batteries for phones and cameras that I could use, which would have all four variables for using in my Blaster:
- Size: small enough to fit in the gun’s handle. No bulky batteries or battery packs.
- Strength of 6 Volts DC as the sum of power: e.g., two small 3 Volt batteries connected in a series.
- An hourly discharge rate of around 1,000 mAh.
- A maximum discharge rate to deliver sufficient power.
At this point it was after 10PM, and Radio Shack and any other electronics store were closed. Best Buy in Union Square was open, in case I wanted to schlep there — but according to their website, their battery types were pretty basic yet expensive (such as $20-40 batteries for Nikon cameras). I decided then that I must go to Radio Shack first thing on Sunday morning and find the next best thing for a replacement — either an obscure battery type, or even if they had special holders for three AAA batteries; the common battery holds for three AAA batteries were only flat, and thus too wide for the handle. I could have theoretically taped three AAA batteries together tightly and crammed them inside the handle, but I wasn’t able to design a method of having three AAAs rigged together with just wires without them coming loose — I needed a real battery holder. After staying up until the small hours, I thought to myself, “This circuit requires 5.5 Volts DC to operate loudly and brightly — what happens if I remove the voltage regulator, and instead power it with just 3 Volts from two AAA batteries?”
Ergo, I tore off the section of the circuit with the voltage regulator and capacitors, and simply wired the two AAAs into the power source. I pulled the trigger a dozen times, and everything worked just fine — albeit with the LEDs slightly dimmer and with the sound slightly quieter. I laughed and thought to myself, “Damn it, I didn’t even need the freakin’ voltage regulator — all I needed was 3 Volts.” Unfortunately, the circuit had specific resistors soldered into it with the intention of using 5.5 Volts — hence, I was unable to remove them to use smaller resistors, and thus had to deal with weaker light/sound from the small power of 3 Volts. Oh well, at least I had a solution to the power issue.
I walked to Rite Aid that late that night for my obligatory energy drink and beef jerky recharge, and picked up a small camera battery from their minuscule electronics section for flashlights and whatnot. I believe the battery had about 3 Volts and 1,000 mAh, but I wasn’t sure of its discharge rate — ergo I never even bothered testing it. It was a mere impulse buy that I purchased in case I felt like using that as the primary source. The next morning I ignored going to Radio Shack, since I fixed the power obstacle, and instead tried to shoot the photos. During Sunday afternoon’s photo shoot, suddenly the unthinkable happened: the gun would randomly stop working in mid-blast. Out of anger and frustration, I turned off my camera and fell back onto the floor, facing the ceiling.
“WHY, DAMN IT!? EDISON!? FRANKLIN?! TESLA!? FORD!!!? MARCONI!?? WHAT THE HELL’S WRONG WITH ME!!?”
Throughout the afternoon and evening, I examined the circuit and tried to see if something came loose, or that if one of my components was poorly-soldered. After hours of troubleshooting, I realized one of the random jump wires to the ground rail came loose, so I had to reattach it. I used my voltage regulator some more on every contact point, and found the problem: the terminal screw block [where the batteries were connected to] was faulty, and its connectors weren’t sufficiently making contact with the V+ and ground terminals. The terminal block was soldered down pretty strong, and couldn’t be removed — so I had to solder in two female header pins and create a bypass to its counterparts on the circuit. This actually worked fine, thus I placed it back in the gun to continue where I left off in the photoshoot. However, more problems randomly occurred out of left field: the header pins for the two wires of the gun’s switch/trigger kept coming loose, and wouldn’t stay in. Next, the two wires for the speaker also kept falling loose from its head pins, and wouldn’t stay down. Hell, I believe even the muzzle flash’s LED wires were coming loose as well. Sometimes I’d pull the trigger and only the lights would blink with no sound, or vice versa. Since I dislike permanently attaching interchangeable parts (such as LEDs, speakers, and switches), I refused to glue down those pieces — after all, if the speakers would randomly die, I’d want to replace them — hence why I used header pins and terminal blocks in the first place. Finally, I just shoved all of the components into their header pins, taped them down with electrical tape, then crammed it back into the gun’s magazine. The show must go on.
I shot all of the photos and recorded the video well until around Sunday night, and stayed up until 2 AM editing all of the media. I had to get up and go to work in a few hours. Later on Monday evening, I had less than six hours to completely write the tutorial on Instructables and publish the entry by 11:59 PM for the contest deadline. I had to write an absurd amount of text to go into graphic detail of building the electronics, and had to make some last minute illustrations and photos for the instructions. I think it was around 11:30 or :45 PM that I hit “publish” and finished the tutorial. I somehow pulled it off.
The whole project was released on social media the next day — to lukewarm reaction, surprise surprise. I noticed something was inherently wrong when the work-in-progress photos in Instagram and Facebook got more likes and comments than the final refined project. Something definitely wasn’t right. I subsequently created an entry for this on LEGO Ideas, which is kind of like Kickstarter: people can submit ideas for original LEGO creations, and when 10,000 votes are reached, the company will personally review the idea and potentially make arrangements for marketing it as a real toy. Of course, you don’t have to pay any money — people simply have to log in and vote. I’m hoping LEGO Group will eventually pick this up as a real product to sell, with some improvements, mind you. Naturally, I wouldn’t recommend using this as an actual prop gun or a movie replica for conventions (like the Force FX Lightsabers), rather this would make a good display model to keep on a shelf in a glass case. Don’t run around playing with this in the backyard — you’ll probably break it. I’m pretty sure this even qualifies as being an assault rifle in the state of California.
Looking back, I don’t regret seemingly wasting my entire summer of 2014 perfecting this project. I was certainly a unique learning experience, which paved the way for further electronics creations such as the Super Mario Power-ups. Not to mention, prior to learning how to use Arduino and build circuits I’d do everything very poorly and crude — such as my giant NES controller. Now that I have a further understanding of microcontrollers and how to assemble small circuits, I plan on rebuilding the innards of the NES controller to be more sophisticated and stronger. I also look forward to getting my own circuit boards printed and manufactured, rather than having to painstakingly build them from scratch. Perhaps I’ll get some kind of universal barebones Arduino circuit made in bulk, so I can create a variety of electronic LEGO trinkets using the same sort of technology as my Blaster’s inner brain.
-Baron von Brunk
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