[Apachexmd] wanted to do something fun for his three-year-old son’s birthday party. Knowing how cool race cars are, he opted to build his own Hot Wheels drag race timer. He didn’t take the easy way out either. He put both his electronics and 3D printing skills to the test with this project.
The system has two main components. First, there’s the starting gate. The cars all have to leave the gate at the same time for a fair race, so [Apachexmd] needed a way to make this electronically controlled. His solution was to use a servo connected to a hinge. The hinge has four machine screws, one for each car. When the servo is rotated in one direction, the hinge pushes the screws out through holes in the track. This keeps the cars from moving on the downward slope. When the start button is pressed, the screws are pulled back and the cars are free to let gravity take over.
The second component is the finish line. Underneath the track are four laser diodes. These shine upwards through holes drilled into the track. Four phototransistors are mounted up above. These act as sensors to detect when the laser beam is broken by a car. It works similarly to a laser trip wire alarm system. The sensors are aimed downwards and covered in black tape to block out extra light noise.
Also above the track are eight 7-segment displays; two for each car. The system is able to keep track of the order in which the cars cross the finish line. When the race ends, it displays which place each car came in above the corresponding track. The system also keeps track of the winning car’s time in seconds and displays this on the display as well.
The system runs on an Arduino and is built almost exclusively out of custom designed 3D printed components. Since all of the components are designed to fit perfectly, the end result is a very slick race timer. Maybe next [Apachexmd] can add in a radar gun to clock top speed. Check out the video below to see it in action. Continue reading “DIY Hot Wheels Drag Race Timer”
Many hobbyists and hackerspaces have the $500 Chinese 40W lasercutters which most of us know are about as successful at etching metals as a featherduster is at drilling. [Frankie] and [Bryan] have figured out a way to use the laser to chemically activate an etching process. See experiment part 2 as well.
First, to be clear, they are using a quality 40W Epilog Zing, not the cheap one, but40W is40W. They mixed the plaster (calcium sulfate) with Isopropyl until it resembled white ketchup. After either thinly painting or airbrushing the material onto the stainless surface (both worked), the mixture is dried with a heatgun then put into the laser. 100% power and 5% speed was what worked for them.
The result was an engrave with a noticeable bite. Something they claim had no effect at all without the mixture.
Stainless steel is an alloy of iron and some chromium – not the same as chrome-plated steel. [Frankie]’s explanation of the chemistry is that the surface layer of the stainless is a transparent chromium oxide. With the heat of the laser, the calcium and chromium swap dance partners. Calcium takes the oxygen and chromium takes the sulfate. The calcium oxide washes off but the chromium sulfate causes the etch.
Next time you’re at your local space, give this a try.
What do you get when you have a computer-controlled laser pointer and a big sheet of glow in the dark material? Something very cool, apparently. [Riley] put together a great build that goes far beyond a simple laser diode and servo build. He’s using stepper motors and a proper motion control software for this one.
The theory behind the device is simple – point a laser at some glow in the dark surface – but [Riley] is doing this project right. Instead of jittery servos, the X and Y axes of the laser pointer are stepper motors. These are controlled by an Arduino Due and TinyG motion control software. This isn’t [Riley]’s first rodeo with TinyG; we saw him at Maker Faire NYC with a pendulum demonstration that was absolutely phenomenal.
Right now, [Riley] is taking SVG images, converting them to Gcode, and putting them up on some glow in the dark vinyl. Since the Hackaday Skull ‘n Wrenches is available in SVG format, that was an easy call to make on what to display in weird phosphorescent green. You can see a video of that along with a few others below.
Continue reading “Drawing On Glow In The Dark Surfaces With Lasers”
HowToLou is back with a rather interesting build: One hundred laser diodes for hair growth.
Before you guffaw at the idea of lasers regrowing hair lost to male pattern baldness, there’s a surprising amount of FDA documents covering the use of laser diodes and red LEDs for hair growth and an interesting study covering teeth regrowth with lasers. Yes folks, it’s a real thing, but something that will never get a double-blind study for obvious reasons.
[Lou] is building his hat with 100 laser diodes, most of which were sourced from Amazon. These diodes were implanted in a piece of foam flooring, a rather interesting solution that puts dozens of diodes in a flexible module that’s pretty good for making a wearable device.
The lasers are powered by three AA batteries, stuffed into a four-slot battery holder that was modified to accommodate a power switch. [Lou] has been wearing a nine-diode hat for a month now, and if the pictures are to be believed, he is seeing a little bit of hair growth. At the very least, it’s an interesting pseudo-medical build that seems to be producing results.
Hats like these are commercially available for about $700. [Lou] built his for about $60. We’re calling that a win even if it doesn’t end up working to [Lou]’s satisfaction. Just don’t look at the lasers with your remaining eye.
Continue reading “Using Lasers for Hair Growth”
MIDI instruments are cool, but they’re not laser cool. That is, unless you’ve added lasers to your MIDI instrument like [Lasse].
[Lasse] started out with an old MIDI keyboard. The plan was to recycle an older keyboard rather than have to purchase something new. In this case, the team used an ESi Keycontrol 49. They keyboard was torn apart to get to the
creamy center circuit boards. [Lasse] says that most MIDI keyboards come withe a MIDI controller board and the actual key control board.
Once the key controller board was identified, [Lasse] needed to figure out how to actually trigger the keys without the physical keyboard in place. He did this by shorting out different pads while the keyboard was hooked up to the computer. If he hit the correct pads, a note would play. Simple, but effective.
The housing for the project is made out of wood. Holes were drilled in one piece to mount 12 laser diodes. That number is not arbitrary. Those familiar with music theory will know that there are 12 notes in an octave. The lasers were powered via the 5V source from USB. The lasers were then aimed at another piece of wood.
Holes were drilled in this second piece wherever the lasers hit. Simple photo resistors were mounted here. The only other components needed for each laser sensor were a resistor and a transistor. This simple discreet circuit is enough to simulate a key press when the laser beam is broken. No programming or microcontrollers required. Check out the demonstration video below to see how it works. Continue reading “MIDI Keyboard with Frickin’ Laser Keys”
[Pierce Brosnan]-era James Bond had a beautiful Omega wristwatch. Of course as with any Bond gadget, it couldn’t just tell time; it needed to do something else. This watch had a laser, and [Patrick] figured he could replicate this build.
This is apretty normal 1.5W laser diode build, stuffed into a wrist-mountable device that will kill balloons. This is really a watch, though: press a button and this thing will tell time.
In the video below, [Patrick] goes over what damage this watch can do. He manages to pop some black balloons, burn holes in a CD case, light a few matches, cut cellotape, and put tiny burn marks in his wall. The battery won’t last long – just a few minutes – but more than enough to propel [Patrick] into Youtube stardom.
There are no plans or tutorials for the build, but the teardown [Patrick] shows is pretty impressive. To stuff a laser diode, battery, and clock into a watch-sized compartment, [Patrick] needed to turn down the metal buttons to fit everything into his watch case.
Because the comments for this post will invariable fill up with concern trolls, we’re just going to say, yes, this is incredibly unsafe, no one should ever do this, and it probably kills puppies.
[Jon] a.k.a. [Pedantite] recently added small-scale laser cutting to his business and thought about using that laser cutter to add some value to some of the many project designs he creates. Yes, this means custom laser cut enclosures, but how to go about it? [Jon] loves automation, and that can only mean automated design of laser cut enclosures by reading the board files from his project library.
The idea of automating the design of plastic enclosures was to read the design files, figure out the dimensions of the board and where the mounting holes go, and generate a file for the laser cutter. The weapon of choice was OpenSCAD, a design language that can be highly parameterized, read external design files, and spit out proper DXF files for laser cutting.
[Jon] set up his toolchain as a Python script that reads design files, sends parameters off to a .SCAD file, and generates a DXF for the laser cutter. There’s also a bit that generates enough data for Blender to render a 3D image of the finished product, all only from gerbers, a drill file, and a few user variables.
The source for these files haven’t been released yet, but that’s only because it’s in a proof-of-concept stage right now. You can check out an example of a render of one of the cases below.
Continue reading “Automated CAD Design for Enclosures”