Here’s a clever hack. Simple, elegant, and eminently cost-effective: using an SMD capacitor to hold your flash media in place!

This is a hack that can pretty much be summed up with just the image at the top of the page — a carefully placed SMD capacitor soldered to a routed tab makes for an extremely cost effective locking mechanism for the nearby SD card slot. There’s just enough flexibility to easily move the capacitor when its time to insert or eject your media.

It’s worth noting that the capacitor in this example doesn’t even appear to be electrically connected to anything. But there’s also no reason you couldn’t position one of the capacitors in your existing bill of materials (BOM). This form of mechanical support will be much cheaper than special purpose clips or mounts. Not a big deal for low-volume projects, but if you’re going high-volume this is definitely something to keep in mind.

If you’re just getting started with SMD capacitors then one of the first things to learn is how to solder them. Also, if you’re hoping to salvage them then try to look for newer equipment which is more likely to have SMD components than through-hole. If you’re planning to use your capacitors for… “capacitance” (how quaint), you can start by learning the basics. And if you want to know everything you can learn about the history of capacitors, too.

Thanks to [JohnU] for writing in to let us know about this one. Have your own natty hacks? Let us know on the tipsline!

NEW PRODUCT: Adafruit Triple Matrix Bonnet for Raspberry Pi
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You can now create large, dazzling LED matrix displays with your Raspberry Pi with the Adafruit Triple Matrix Bonnet for Raspberry Pi. This boards plugs into your Raspberry Pi with 2×20 header, and makes it super easy to control three parallel strings of HUB75 RGB matrices such as those we stock in the shop and create colorful scrolling displays or mini LED walls with ease.

Unlike our single-panel Matrix Bonnet, this board can drive 3 panels in parallel, also known as “active3” pinout. This means it can handle approximately 3x as many panels/pixels. However, as a trade-off, the power management is not done on-board. Instead you will have to provide the 5V 10A+ power separately! We recommend two power distribution bus bars, they’re good for many amps and make wiring easier.

• “Bonnet” boards work on Raspberry Pi with a 40-pin GPIO header — Zero, Zero W/WH, Model A+, B+, Pi 2, Pi 3, Pi 4, Pi 5 They do not work with older 26-pin boards like the original Model A or B. Note with the Pi Zero, you may need to solder a header on the Pi board; it’s normally unpopulated on that model. For best performance we recommend a Pi 4 or Pi 5.
• For Pi 0, 2, 3, and 4 we recommend the rpi-rgb-matrix driver, with C and Python bindings. It works great, just select the standard/active3 pinout.
• For Pi 5+, we recommend using our PIO-based matrix driver which supports up to 3 panels – check the guide for the demo code for the triple bonnet
• By default the bonnet has a slim 2×20 header on it. If you need to ‘lift’ the bonnet above an enclosure, pick up a 2×20 riser header.
• If you want to get access to GPIO while the bonnet is installed, pick up a 2×20 stacking header – the pins will slide through the socket and you can plug something else on top.

This bonnet will make your mega-matrix projects super easy and avoid wiring complexity and mistakes:

• Simple design – plug in IDC cables, provide separate power to each panel, run our Python code!
• Onboard level shifters to convert the RasPi’s 3.3V to 5.0V logic for clean and glitch free matrix driving
• Fully assembled compact design no soldering required! Plugs onto any Raspberry Pi with a 2×20 connector, and you’re ready to glow.

Works with any of our 16×32, 32×32, 32×64, or 64×64 RGB LED Matrices with HUB75 connections. When using with 64×64 you can select whether the Address E pin is on the 4’th or 8’th IDC pad with an on-board switch. Want even more lights? No problem, chain multiple matrices together for a longer display. The bigger the display the harder it is on the Pi, so keep that in mind if you’re using a lower-powered Pi Zero.

Please note: this Bonnet is only for use with HUB75 type RGB matrices. Not for use with NeoPixel, DotStar, or other ‘addressable’ LEDs.

Each order comes with a fully assembled and ready to go bonnet with all parts assembled. RGB Matrix is not included, please check out our fine selection

In stock and shipping now!

Shared by greenribbit on Thingiverse:

I wanted a way to keep my DuPont wires together and organized but wasn’t a big fan of the big clunky comb-style organizers. So I made my own!

This organizer can hold about 20 to 22 wires at a time. The wires I have are about 195mm long (excluding the plastic connectors). Fully packet, the organizer has a foot print of roughly 25mm by 125 mm.

Keep in mind I print with a 0.8mm nozzle @ 0.4mm layer height. So, this model is optimized for that configuration. It should print fine if you use a different nozzle diameter and layer height, but no guarantees!

There is a slight technique to inserting the wires into the organizer. Basically, hold the organizer in one hand, and press the wire against the slot with the thumb on that hand, while using your other hand to kind of “wind” the wire around the curve. I know, I know…trust me it is easier than it sounds and it keeps your wires nice and snug!

Download the files and learn more

Every Thursday is #3dthursday here at Adafruit! The DIY 3D printing community has passion and dedication for making solid objects from digital models. Recently, we have noticed electronics projects integrated with 3D printed enclosures, brackets, and sculptures, so each Thursday we celebrate and highlight these bold pioneers!

Have you considered building a 3D project around an Arduino or other microcontroller? How about printing a bracket to mount your Raspberry Pi to the back of your HD monitor? And don’t forget the countless LED projects that are possible when you are modeling your projects in 3D!

If you have never heard of the Bellmac-32, you aren’t alone. But it is a good bet that most, if not all, of the CPUs in your devices today use technology pioneered by this early 32-bit CPU. The chip was honored with the IEEE Milestone award, and [Willie Jones] explains why in a recent post in Spectrum.

The chip dates from the late 1970s. AT&T’s Bell Labs had a virtual monopoly on phones in the United States, but that was changing, and the government was pressing for divestiture. However, regulators finally allowed Bell to enter the computing market. There was only one problem: everyone else had a huge head start.

There was only one thing to do. There was no point in trying to catch the leaders. Bell decided to leap ahead of the pack. In a time when 8-bit processors were the norm and there were nascent 16-bit processors, they produced a 32-bit processor that ran at a — for the time — snappy 2 MHz.

At the time (1978), most chips used PMOS or NMOS transistors, but Bellmac-32 used CMOS and was made to host compiled C programs. Problems with CMOS were often addressed using dynamic logic, but Bell used a different technique, domino logic, to meet their goals.

Domino logic lets devices cascade like falling dominoes in between clock pulses. By 1980, the device reached 2 MHz, and a second generation could reach speeds of up to 9 MHz. For contrast, the Intel 8088 from 1981 ran at 4.77 MHz and handled, at most, half the data in a given time period as the Bellmac-32. Of course, the 68000 was out a year earlier, but you could argue it was a 16-bit CPU, despite some 32-bit features.

It is fun to imagine what life would be like today if we had fast 32-bit Unix machines widely available in the early 1980s. History has shown that many of Bellmac’s decisions were correct. CMOS was the future. Many of the design and testing techniques would go on to become standard operating procedure across the industry. But, as for the Bellmac-32, it didn’t really get the attention it deserved. It did go on in the AT&T 3B computers as the WE 32×00 family of CPUs.

You can check out a 1982 promo video about the CPU below, which also explains domino logic. Instruction sets have changed a bit since then. You can see a 68000 and 8086 face off, and imagine how the Bellmac would have done in comparison.