Hacking A $6000 Cotton Candy Machine To Fully Control It

August 7, 2026 by Maya Posch 6 Comments

Some of the cotton candy options by the machine. The Chinese text reads 'flower type'. — Some of the cotton candy options by the machine. The Chinese text reads ‘flower type’.

Having a fully automated cotton candy vending machine in your possession is a great thing, but not if you do not have full access to its software. With [Block’s Retro Repairs] getting ghosted by the manufacturer on regaining account access to the machine he bought used for $300, there was little left but to try and break into the system.

We previously covered the journey in getting the vending machine back into a state where it’d actually reliably produce cotton candy again, a process which is quite tedious and temperamental. After a lot of fiddling with sensors and temperature settings this was fixed, but still left the issue that as a vending machine it should allow the owner to set prices and such. Sadly this could only be done remotely via a special account, which access to had been left with the previous owner.

Despite the very custom exterior, the vending machine runs what is effectively an Android system, consisting of an industrial computer board wired into a lot of stepper drivers and other control boards. To the extreme delight of everyone involved, it was possible to access the Ct Terminal application with adb and its product database on the device’s storage. Unfortunately writing back a changed database file didn’t change anything in the UI, so for a few months the project languished.

After nearly bricking the system and ending up factory resetting the control software including temperatures, it actually improved the performance of the machine and produced cotton candy, so that was one win. Ultimately the solution was to modify the original app, but a combination of weak coding skills and the app being in Chinese led him to use free LLM coding chatbots to assist here.

This resulted in a custom settings menu being added with the ability to modify pricing, no need for online access any more and a very nice cotton candy vending machine for the private arcade where presumably friends and family can enjoy cheap or even free cotton candy. Finally having the machine sealed against ant intrusion was also a major improvement.

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Tearing Down Aircraft Weather Radar Avionics

August 4, 2026 by Zoe Skyforest 1 Comment

If you’re flying high in the sky, it’s useful to know if there’s turbulence, heavy rain, or other nasty weather ahead. Onboard weather radar is a useful tool that pilots use to scope out conditions ahead. [Thomas Scherrer] came into possession of a weather radar display from a vintage aircraft, and decided to tear it apart for our viewing pleasure.

The unit in question is a Bendix PPI-1 plan position indicator. This particular 1971 example was scored from a McDonnell-Douglas DC9. [Thomas] only has the display itself, not the radar that would feed it or the power supply to turn it on. Still, even just the readout unit is super interesting to look inside. Right off the bat, there’s a neat dimming filter on the front, and the case itself is really beautifully designed for service. The design is very much of its time, full of neat wire harnesses and chunky through-hole components. There are some neat surprises inside, too, like an interesting device shaped like a triangular prism whose purpose we won’t spoil here.

If you’re wondering what one of these units looks like in action, you can see such an example on YouTube. The display basically lights up in areas where there were stronger radar returns indicating weather to be avoided.

We love radars around these parts, and we feature them all the time. Video after the break.

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Duplicating Parts Using Silicone Molds

July 26, 2026 by Zoe Skyforest 18 Comments

[Do As I Do] had a simple task to complete. A couple of small parts needed to be duplicated in some quantity, with good dimensional accuracy and surface finish. There are a number of ways you might go about this, particularly if you have the original tooling or a machine shop on hand. In this case, however, the plan was to duplicate the parts with silicone molds.

The first step, naturally, was to produce the silicone molds. Doing this involved some craft supplies, with glossy paper and hot glue used to create a vessel for casting silicone around the original parts. The silicone itself was mixed carefully and poured into the vessels, and soon enough [Do As I Do] had a pair of negative molds that could be used to produce duplicates of the original. The original parts were removed, and the silicone molds were filled with resin over and over again to make as many duplicates as were needed.

This was a simple enough project with straightforward geometry that suited the process. More challenging parts would require more care in mold prep and more advanced techniques. Depending on material choice for the duplicate parts and other factors like intended final application, extra steps like degassing may be necessary, too. Still, for a quick guide on duplicating a simple plastic part, it’s hard to beat.

We’ve featured other silicone mold jobs before, like these impressive recreated tail light lenses. Video after the break.

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Delta Pen Plotter Draws In Multiple Colors

July 26, 2026 by Zoe Skyforest 15 Comments

If you’re building your first plotter, or you just like thinking in right angles, you’d probably consider a Cartesian design for your build. [András Vujovits] went another route with his project, building an impressive delta pen plotter with a useful tool changer, to boot.

The build relies on a unique motion system, wherein two NEMA 17 stepper motors drive either side of the linkage to control the position of the end effector—in this case, a pen carriage. By controlling the position of each side of the mechanism, it’s possible to move the pen through XY space. Running the show is an Arduino Nano, fitted with a GRBL shield and appropriate stepper motor drivers.

The magnetic tool changer is particularly nifty, too. It allows the plotter to grab a different ink at will to add more color to the drawing. It’s well-designed, with the plotter able to change inks without losing accuracy or otherwise fumbling the switchover. The plotter uses Muji ball point pens, which are available in a range of colors and draw with slick, clean lines. It’s also quite a fast plotter, thanks in part to [András]’s efforts to keep the pen carriage light by using a smart mechanism to offload the pen lifting actuator to the main body.

[András] has plans available, but you’re going to have to pay for them. Still, it’s always nice to see a new machine in the wild. Video after the break.

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Building A Fencing Scoring Box

July 25, 2026 by Zoe Skyforest No comments

The sport of fencing requires keeping score, just like so many other similar pastimes. When their club’s existing scoring rig broke, [jc0025] stepped up to build a scoring box of their own, using the typical tools of the maker trade.

The brains of the operation is an Arduino Nano, running the venerable ATmega328P. It’s set up to drive a pair of 8×8 WS2812B addressable LED panels. It’s also hooked up to a pair of fencing socket blocks, which hook up to the lamé (jacket), weapon, and guard of each player for electronically scoring hits. The Arduino is thus programmed to respond to various conditions, lighting the LEDs in turn. For example, the tip of one player’s weapon hitting the other player’s lamé will fire a colored light, allowing the hit to be scored. Meanwhile, a tip hitting the floor will fire a white light, indicating off-target. There’s also a buzzer for sonic indication, as well. Everything is wrapped up in a tidy 3D-printed housing, while power is courtesy of a USB-C charger hooked up to the unit.

If you’re looking to replace some old broken fencing scoring gear on the cheap, this project is probably a good place to start. We’ve featured some other great scoreboard projects over the years, too. Meanwhile, if you’re whipping up your custom own gear for your local sporting club, we might like to hear about it on the tipsline.

A Train Departure Board For The Home

July 23, 2026 by Zoe Skyforest 10 Comments

Trains are a great way to get around. You just have to make sure you’re across the schedule if you intend to get where you’re going in a timely manner. Train departure boards exist for that very purpose. As a train fan, [Jon] always wanted such a thing, so decided to build one for himself.

The build started, as so many do, with a Raspberry Pi 4, with [Jon] deciding on the 1GB model. Hooked up to either an Adafruit RGB Matrix Bonnet, or an Electrodragon 3-port RGB Matrix board, it’s then possible to get the Pi running three to four HUB75E LED matrixes. Each matrix consists of 128 x 64 pixels, so stacking up a bunch of them can make a nicely-sized departure board that’s easily readable. [Jon] was sure to hook up a nice, juicy 5-amp 5-volt power supply to ensure there wouldn’t be any surprise brownouts under normal usage conditions. From there, it’s simply a matter of having the Pi query the Rail Data Marketplace in order to get the relevant schedule data to display on the board.

If you want to get information on your local rail services at a glance, or just want to impress your fellow foamers at your next railfan gathering, a build like this is a great way to go. We’ve seen similar builds before, too. Video after the break.

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Mic Jammer Relies On Ultrasound

July 23, 2026 by Zoe Skyforest 15 Comments

Today’s phone microphones are perfectly adept at picking up sound in all sorts of conditions, and they’re backed by all kinds of processing techniques to filter out noise and capture clean audio. [mcore1976] has been working on a device to jam phone microphones that might be listening in, however, countering fancy processing techniques in turn.

The build uses a microcontroller brain to control an array of ultrasonic transducers. [mcore1976] has created many revisions of the project, each time improving its ability to jam microphones in modern hardware. The latest revision uses an RP2040 microcontroller and a MOSFET drive stage to control 20-80 ultrasonic transducers. They’re driven with a PWM signal generated from the RP2040 itself. The signal output is specifically modulated to try and confuse the automatic gain control systems used in many modern phones in order to make it difficult for them to record clear audio when the jammer is running. As [mcore1976] demonstrates with an iPhone 17, his voice is completely lost amidst unintelligible garbled noise while the jammer is switched on.

It’s a niche idea, and perhaps most interesting because it affects phone microphones while being largely inaudible to the human ear. We’ve featured other interesting jamming devices of late, too. Video after the break.

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