Laser Draws Weather Report

Have you ever wished that a laser could tell you the weather? If you have, then [tuckershannon] has you covered. He’s created a machine that uses a laser and some UV sensitive paper to draw the temperature and a weather icon! And that’s not all! It’s connected to the internet, so it can also show the time and print out messages.

Building on [tuckershannon]’s previous work with glow-in-the-dark drawing, the brains inside this machine is a Raspberry Pi Zero. The laser itself is a 5mw, 405nm laser pointer with the button zip-tied down. Two 28BYJ-48 stepper motors are used to orient the laser, one for the rotation and another for the height angle. Each stepper motor is connected to a motor driver board and then wired directly to the Pi.

The base and arm that holds the laser were designed in SolidWorks and then 3d printed. The stepper motors are mounted perpendicular to one another and then the laser pointer mounted at the end. The batteries have been removed from the laser and the terminals are also wired directly to the raspberry pi. The Pi is then connected to Alexa via IFTTT so that it can be controlled by voice from anywhere.

The real beauty of [tucker]’s laser drawing machine is that is will draw out the temperature and weather icon, as well as drawing the time in either digital or analog forms! We’ve seen [tuckershannon]’s work before. The precursors to this project were his clock which uses a robotic arm with a UV LED on it to draw the time and another clock which uses similar robotic arm only with a laser attached. Let’s hope we get to see the rest of [tucker]’s progress!

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Laser Cutter Turns Scrapped To Shipped

We’ll go way out on a limb here and say you’ve probably got a ridiculous amount of flattened cardboard boxes. We’re buying more stuff online than ever before, and all those boxes really start to add up. At the least we hope they’re making it to the recycling bin, but what about reusing them? Surely there’s something you could do with all those empty shipping boxes…

Here’s a wild idea…why not use them to ship things? But not exactly as they are, unless you’re in the business of shipping big stuff, the probably won’t do you much good as-is. Instead, why not turn those big flattened cardboard boxes into smaller, more convenient, shippers? That’s exactly what [Felix Rusu] has done, and we’ve got to say, it’s a brilliant idea.

[Felix] started by tracing the outline of the USPS Priority Small Flat Rate Box, which was the perfect template as it comes to you flat packed and gets folded into its final shape. He fiddled with the design a bit, and in the end had a DXF file he could feed into his 60W CO2 laser cutter. By lowering the power to 15% on the fold lines, the cutter is even able to score the cardboard where it needs to fold.

Assuming you’ve got a powerful enough laser, you can now turn all those Amazon Prime boxes into the perfect shippers to use when your mom finally makes you sell your collection of Yu-Gi-Oh! cards on eBay. Otherwise, you can just use them to build a wall so she’ll finally stay out of your side of the basement.

[Thanks to Adrian for the tip.]

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Joe Grand is Hiding Data in Plain Sight: LEDs that Look Solid but Send a Message

Thursday night was a real treat. I got to see both Joe Grand and Kitty Yeung at the HDDG meetup, each speaking about their recent work.

Joe walked us through the OpticSpy, his newest hardware product that had its genesis in some of the earliest days of data leakage. Remember those lights on old modems that would blink when data is being transmitted or received? The easiest way to design this circuit is to tie the status LEDs directly to the RX and TX lines of a serial port, but it turns out that’s broadcasting your data out to anyone with a camera. You can’t see the light blinking so fast with your eyes of course, but with the right gear you most certainly could read out the ones and zeros. Joe built an homage to that time using a BPW21R photodiode.

Transmitting data over light is something that television manufacturers have been doing for decades, too. How do they work in a room full of light sources? They filter for the carrier signal (usually 38 kHz). But what if you’re interested in finding an arbitrary signal? Joe’s bag of tricks does it without the carrier and across a large spectrum. It feels a bit like magic, but even if you know how it works, his explanation of the hardware is worth a watch!

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A Lesson in K40 Laser Repair

The K40 laser cutter has become ubiquitous in hackerspaces and well-equipped home workshops over the past few years, as a relatively inexpensive introduction to laser cutting and a machine that is readily hackable. Tokyo Hackerspace have one, but sadly their laser tube failed after relatively little use. Replacing a laser tube might be a routine component change for some readers, but it’s still worth looking at in some detail.

Their tube had failed at its output lens cooling cap, a component that is glued onto the end of the tube rather than bonded, and which had snapped off. There had been no mechanical stress upon it, but it was found  that the arrangement of their cooling system caused it to drain between uses and thus air bubbles could accumulate. The resulting cooling inefficiency caused enough thermal stress for the bond between the tube and the end piece to fail.

The in-depth analysis of what caused the failure and step-by-step description of the procedure should be of interest to any K40 owner. Little things such as ensuring that the tube is rotated to the right angle for all air bubbles to make their way out of it, or making sure that when the pump is switched off the water isn’t all pulled out of it by gravity seem obvious, but these are traps that will have caught more than one K40 owner.

We’ve covered many K40 stories over the years, but a good place to start for the novice might be this commissioning story, or even this tale of a hackerspace’s modifications to their model.

Hacking a Cheap Laser Rangefinder

When a new piece of technology comes out, the price is generally so high that it keeps away everyone but the die hard early adopters. But with time the prices inch down enough that more people are willing to buy, which then drives the prices down even more, until eventually the economies of scale really kick in and the thing is so cheap that it’s almost an impulse buy. Linux SBCs, Blu-ray lasers, 3D printers; you name it and the hacker community has probably benefited from the fact that it’s not just the hacker community that’s interested anymore.

Which is exactly what’s started to happen with laser rangefinders. Once almost exclusively a military technology, you can now pick a basic “laser tape measure” for less than $40 USD from the normal overseas suppliers. Unfortunately, as [iliasam] found, they aren’t particularly well suited other tasks. For one there’s no official way of getting the data out of the thing, but the other problem is that the sample rate is less than one per second. Believing the hardware itself was promising enough, he set out to reverse engineer and replace the firmware running on one of these cheap laser rangefinders (Google Translate from Russian).

His blog post is an absolute wealth of information on how these devices operate, and a must read for anyone interested in reverse engineering. But the short version is that he figured out a way to reprogram the STM32F100C8T6 microcontroller used in the device, and develop his own firmware that addresses the usability concerns of this otherwise very promising gadget.

With some minor hoop jumping, the laser tape measure PCB can be hooked up to an ST-Link programmer, and the firmware provided by [iliasam] can be used to enable an easy to use serial interface. Perfect for pairing with an Arduino or Raspberry Pi to get fast and accurate range data without breaking the bank.

It probably won’t surprise you to see this isn’t the first time [iliasam] has gotten down and dirty with a laser rangefinder. This extremely impressive build from last year allowed for incredibly accurate 3D scans of his room, and before that he created his own rangefinder from scratch.

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Gorgeous NickelBot Serves Up Lasered Wooden Nickels

[bdring] just recently completed his absolutely fantastic NickelBot, which is a beautifully made unit that engraves small wooden discs with a laser like some kind of on demand vending machine, and it’s wonderful. NickelBot is small, but a lot is going on inside. For example, there’s a custom-designed combination engraving platform and hopper that takes care of loading a wooden nickel from a stack, holding it firm while it gets engraved by a laser, then ejects it out a slot once it’s done.

NickelBot is portable and can crank out an engraved nickel within a couple of minutes, nicely fulfilling its role of being able to dish out the small items on demand at events while looking great at the same time. NickelBot’s guts are built around a PSoC5 development board, and LaserGRBL is used on the software side to generate G-code for the engraving itself. Watch it work in the video embedded below.

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Laser projector ditches galvanometer for spinning drum

Laser projectors like those popular in clubs or laser shows often use mirror galvanometers to reflect the laser and draw in 2D. Without galvos, and on a tight budget, [Vitaliy Mosesov] decided that instead of downgrading the quality, he would seek an entirely different solution: a spinning mirror drum.

He fires a laser at a rotating drum with twelve mirror faces, each at a different adjustable vertical angle. The laser will hit a higher or lower point on the projection surface depending on which mirror it’s reflecting off – this creates resolution in the Y direction.

Timing the pulsing of the laser so that it reflects off the mirror at a certain horizontal angle provides the X resolution.

As you can already tell, speed and timing is critical for this to work. So much so that [Vitaliy] decided he wanted to overclock his Arduino – from 16 MHz to 24.576 MHz. Since this changes the baud rate, an AVR ISP II was used for programming after the modification, and the ‘duino’s hardware serial initialization had to be hacked too.

For the laser itself, [Vitaliy] designed some nifty driver circuitry, which can respond quickly to the required >50 kHz modulation, supply high current, and filter out voltage transients on the power supply (semiconductor lasers have no protection from current spikes).

On the motor side of things, closed loop control is essential. A photo-interrupter was added to the drum for exact speed detection, as well as a differentiator to clean up the signal. Oh, and did we mention the motor is from a floppy disk drive?

We’ve actually seen builds like this before, including a dot-matrix version with multiple lasers and one made apparently out of Meccano and hot-glue that can project a Jolly Wrencher. But this build, with its multiple, adjustable mirrors, is a beauty.  Check it out in action below.

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