Marimbatron: A Digital Marimba Prototyping Project

The Marimbatron is [Leo Kuipers] ‘s final project as part of the Fab Academy program supervised by [Prof. Neil Gershenfeld] of MIT’s Center for Bits and Atoms. The course aims to teach students how to leverage all the fab lab skills to create unique prototypes using the materials at hand.

The final polyurethane/PET/Flex PCB stack-up for the sensor pad

Fortunately, one of the main topics covered in the course is documentation, and [Leo] has provided ample material for review. The marimba consists of a horizontal series of wooden bars, each mounted over a metal resonator tube. It is played similarly to the xylophone, with a piano-type note arrangement, covering about five octaves but with a lower range than the xylophone. [Leo] converted this piano-type layout into a more logical grid arrangement. The individual pads are 3D printed in PETG and attached to a DIY piezoresistive pressure sensor made from a graphite-sprayed PET sheet laid upon a DIY flexible PCB. A central addressable LED was also included for indication purposes. The base layer is made of cast polyurethane, formed inside a 3D-printed rigid mould. This absorbs impact and prevents crosstalk to nearby sensors. The sensor PCB was initially prototyped by adhering a layer of copper tape to a layer of Kapton tape and cutting it out using a desktop vinyl cutter. While this method worked for the proof of concept, [Leo] ultimately outsourced the final version to a PCB manufacturer. The description of prototyping the sensor and dealing with over-moulding was particularly fascinating.

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2024 Business Card Challenge: Adding Some Refinement To Breadboard Power Supplies

For small electronics projects, prototyping a design on a breadboard is a must to iron out kinks in the design and ensure everything works properly before a final version is created. The power supply for the breadboard is often overlooked, with newcomers to electronics sometimes using a 9V battery and regulator or a cheap USB supply to get a quick 5V source. We might eventually move on to hacking together an ATX power supply, or the more affluent among us might spring for a variable, regulated bench supply, but this power supply built specifically for breadboards might thread the needle for this use case much better than other options.

The unique supply is hosted on a small PCB with two breakout rails that connect directly to the positive and negative pins on a standard-sized breadboard. The power supply has two outputs, each of which can output up to 24V DC and both are adjustable by potentiometers. To maintain high efficiency and lower component sizes, a switch-mode design is used to provide variable DC voltage. A three-digit, seven-segment display at the top of the board keeps track of whichever output the user selects, and the supply itself can be powered by a number of inputs, including USB-C or lithium batteries.

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Sandwizz Promises To Reinvent The Breadboard

The solderless breadboard is perhaps the electronic hobbyist’s most commonly used tool, but let’s be honest, it isn’t exactly anyone’s favorite piece of gear. Even if you’ve got an infinite supply of jumpers in just the right size, any mildly complex circuit quickly becomes a nightmare to plan out and assemble. To say nothing of the annoyance of trying to track down an intermittent glitch, only to find you’ve got a loose wire someplace…

The Sandwizz Breadboard hopes to address those problems, and more, by turning the classic breadboard into a high-tech electronics prototyping platform. The Sandwizz not only includes an integrated power supply capable of providing between 1.8 and 5 volts DC, but also features an array of integrated digital and analog components. What’s more, the programmable connection system lets you virtually “wire” the internal and external components instead of wresting with jumper wires.

To configure the Sandwizz, you just need to connect to the device’s serial interface with your favorite terminal emulator and work your way through its text-based menus. You can also export a netlist file from your KiCad schematic and upload it into the board to make all the necessary connections automatically. This lets you make the leap from concept to physical prototype in literally seconds.

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No Solder! Squeeze Your Parts To The PCB

What’s solder for, anyway? It’s just the stuff that sticks the parts to the PCB. If you’re rapid prototyping, possibly with expensive components, and want to be able to remove chips from the board easily when you spin up the next iteration, it would be great if you didn’t have to de-solder them to move on. If only you could hold the parts without the solder…

That’s exactly the goal behind [Zeyu Yan] et al’s SolderlessPCB, which uses custom 3D printed plastic covers to do the holding. And it has the knock-on benefit of serving as a simple case.

In their paper, they document some clever topologies to make sure that the parts are held down firmly to the board, with the majority of the force coming from screws. We especially like the little hold-down wings for use with SMD capacitors or resistors, although we could absolutely see saving the technique exclusively for the more high value components to simplify design work on the 3DP frame. Still, with the ability to automatically generate 3D models of the board, parts included, this should be something that can be automated away.

The group is doing this with SLA 3D printing, and we imagine that the resolution is important. You could try it with an FDM printer, though. Let us know if you do!

This is the same research group that is responsible for the laser-cut sheet-PCB origami. There’s clearly some creative thinking going on over there.

What The Artisan 3-in-1 CNC Offers (If One Has The Table Space)

I never feel like I have enough space in my workshop. The promise of consolidating tools to make the most of limited space drew me to the Snapmaker Artisan, a plus-sized 3-in-1 tool combining 3D printer, laser engraver, and CNC machine.

Smaller than three separate tools, but still big.

Jacks of all trades may be masters of none, but it is also true that a tool does not need to be a master of its functions to be useful. For many jobs, it enough to simply be serviceable. Does a machine like the Artisan offer something useful to a workshop?

Snapmaker was kind enough to send me an Artisan that I have by now spent a fair bit of time with. While I have come to expect the occasional glitch, having access to multiple functions is great for prototyping and desktop manufacturing.

This is especially true when it allows doing a job in-house where one previously had to outsource, or simply go without. This combo machine does have something to offer, as long as one can give it generous table space in return.

What It Is

The Artisan is a large dual-extrusion 3D printer, CNC router, and diode-based laser engraver. To change functions, one physically swaps toolheads and beds. Very thankfully, there are quick-change fixtures for this.

Driving the Artisan is Snapmaker’s software Luban (GitHub respository). Named for the ancient Chinese master craftsman, it is responsible for job setup and control. For laser and CNC work, there are convenient built-in profiles for a variety of paper, plastic, leather, and wood products.

The unit is enclosed, nicely designed, and — while I have come to expect the occasional glitch — serviceable at all three of its functions. The size and stature of the machine warrants some special mention, however.

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Supercon 2022: Carrie Sundra Discusses Manufacturing On A Shoestring Budget

Making hardware is hard. This is doubly true when you’re developing a niche hardware device that might have a total production run in the hundreds of units instead of something mass market. [Carrie Sundra] has been through the process several times, and has bestowed her wisdom on how not to screw it up.

The internet is strewn with the remains of unfulfilled crowdfunding campaigns for tantalizing devices that seemed so simple when they showed of the prototype. How does one get something from the workbench into the world without losing their life savings and reputation?

[Sundra] walks us through her process for product development that has seen several products successfully launch without an army of pitchfork-wielding fiber crafters line up at her door. One of the first concepts she stresses is that you should design your products around the mantra, “Once it leaves your shop IT SHOULD NEVER COME BACK.” If you design for user-serviceability from the beginning, you can eliminate most warranty returns and probably make it easier to manufacture your widget to boot. Continue reading “Supercon 2022: Carrie Sundra Discusses Manufacturing On A Shoestring Budget”

What Does It Take For A LEGO Car To Roll Downhill Forever?

Cars (including LEGO ones) will roll downhill. In theory if the hill were a treadmill, the car could roll forever. In practice, there are a lot of things waiting to go wrong to keep this from happening. If you’ve ever wondered what those problems would be and what a solution would look like, [Brick Technology] has a nine-minute video showing the whole journey.

The video showcases an iterative process of testing, surfacing a problem, redesigning to address that problem, and then back to testing. It starts off pretty innocently with increasing wheel friction and adding weight, but we’ll tell you right now it goes in some unexpected directions that show off [Brick Technology]’s skill and confidence when it comes to LEGO assemblies.

You can watch the whole thing unfold in the video, embedded below. It’s fun to see how the different builds perform, and we can’t help but think that the icing on the cake would be LEGO bricks with OLED screens and working instrumentation built into them.

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