Mat Boards Are Spendy, So DIY CNC Tool To The Rescue

Mats are flat pieces of paper-based material that fill the space between a frame and the art within. They perform a number of aesthetic and practical functions, and they can also be expensive to purchase. Making them by hand is an option, but it’s an exacting process. [wooddragon48] felt that a CNC solution would serve this need nicely, and began designing a DIY CNC tool to do exactly that.

One of the tricky parts about cutting mat boards is that cuts are at an angle, and there is really no tolerance for overcuts or any kind of visual blemish. CNC control would seem to offer a great solution to both the need for precisely straight cuts, as well as fine control over where cuts begin and end in a way that opens the door to complex designs that would be impractical to do by hand.

[wooddragon48]’s design has an angled cutter designed to plunge perfectly on demand, surrounded by a ring — similar to that on a router — which ensures the cutting tool is always consistently positioned with the material. It’s still in the design phase, but this is a type of tool that doesn’t yet exist so far as we can tell. The ability to CNC cut mat board, especially in complex designs, would be a huge timesaver.

Art and DIY CNC have a long history of happy intersection, as we have seen with a CNC router repurposed for string art, a CNC painting robot, and even an interactive abstract sculpture generator.

Your Engineering Pad In Browser

It was always easy to spot engineering students in college. They had slide rules on their belts (later, calculators) and wrote everything on engineering pads. These were usually a light brown or green and had a light grid on one side, ready to let you sketch a diagram or a math function. These days, you tend to sketch math functions on the computer and there are plenty of people willing to take your money for the software. But if you fire up your browser, head over to and you might save a little cash.

Although it looks a lot like a Jupyter notebook, the math cells in EngineeringPaper keeps track of units for you and allows you to query results easily. Want to read more? Luckily, there is an EngineeringPaper worksheet that explains how to use it. If you prefer your explanations in video form, check out their channel, including the video that appears below.

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Google Nest Hub Teardown

Seeing the guts of devices is a fascination that many hackers share. [Txyz] tore down a 2nd gen Google Nest Hub for all of us to enjoy. The video after the break is well produced and relaxing to watch as various heat shields are removed and debug cables are soldered on.

The main SOC is an Amlogic S905D3G, a 4-core A55-based SoC. The important chips are meticulously documented, and it’s a fascinating look inside a device common in many people’s homes. One chip that’s of note is the BGT60TR13C, otherwise known as Project Soli. It is an 8x10mm chip that uses radar to detect movement with sub-millimeter accuracy. This allows the device to measure your sleep quality or recognize gestures. Luckily for us, [Txyz] has included a datasheet and a block diagram. First, the chip fills a FIFO with data samples. Once full, it will issue an interrupt to the main SoC, which empties the buffer via SPI.

The debug cables allowed him to capture traces of the SPI commands to the BGT60TR13C. [Txyz] focused on decoding the various data blocks and the configuration registers. Unfortunately, only a few registers are documented in the datasheet, and it isn’t apparent what they do.

If a hardware teardown isn’t enough for you, perhaps a software teardown to bypass Secure Boot might sate your interest.

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Automate Handwritten Postcards With Robots

As someone notorious for not doing things the old-fashioned manual way, we’re not sure by [Shane] of Stuff Made Here was thinking when he promised to send out a few hundred handwritten letters. Predictably he built an automated production line for the task. Video after the break.

With “handwritten” and “automated” not being particularly compatible, [Shane] set out to create a robot to create believable handwritten letters, which is significantly harder than it may seem at first glance. It turns out that turning your handwriting into a font is too consistent to be believable, which led down the rabbit of generated handwriting. [Shane] first spend a ridiculous amount of time trying to implement a machine learning model for the task, only to find there’s already an open source library good enough to fool a forensic handwriting expert.

On the robot side, [Shane] used a pen plotter from Amazon that’s it’s actually cheaper than building one from scratch. With the “handwriting” taken care of, [Shane] set up an automated loading system with the industrial robot arm he also used for his CNC chainsaw. The feeders for the empty and full postcards are 3D printed with a spring-loaded mechanism to keep the top card at the same height all the time.

Although this project contained less custom hardware and software than [Shane’s] other projects, it served as an excellent reminder that it’s unnecessary to reinvent the wheel when building a car. It’s easy to get caught up in the small details of a project that don’t matter much in the final implementation and usage.

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Hackaday Prize 2023: Scratch Made 8-Bit Educational Computer

To demonstrate the functionality of an 8-bit computer processor at a very basic level,  [Mazen Gomaa] assembled a Homemade 8-Bit Educational Computer using common CMOS logic chips, a handful of prototyping boards, and an impressive number of carefully connected wires. [Mazen] was inspired by Ben Eater’s 8-bit TTL Breadboard Computer but opted to solder the chips and other components onto proto boards instead of using solderless breadboards.

The 8-Bit computer is based on the Simple-As-Possible (SAP) computer architecture described in the book “Digital Computer Electronics” by [Paul Malvino] and [Jerald Brown]. These useful educational examples demonstrate data, computer logic, and even programming in the context of basic electronic components. Tinkering with such simple computers provides a real “zeros and ones” exposure to computation.

[Mazen] added some additional features and functionality to his computer, including an instruction keypad, an address keypad, a dot matrix memory data viewer, a Schottky diode matrix ROM, and a boot loader that initializes the RAM with data stored in ROM. With clock speeds up to 100 Hz, the computer consumes around 300-500 mA of current.

Future plans include expanding the memory and instruction set from the present 128-bit (8×16) RAM, 64-bit (8×8) ROM, and a set of ten instructions.  Already, this project is a great addition to an ever-growing catalog of homemade solderless breadboard computers, LCD snake games, and VGA video cards.

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All Your Robots Are Belong To Us: You Just Rent Them

Monthly bills. Everyone has them. Except if you go far enough back, not everyone had them. After all, you might live in a home your family has owned for generations. You might be able to produce all the basic necessities using your homestead: food from a garden, water from a well, textiles, soap, and candles. You might have to buy the occasional animal, but your recurring bills could be modest outside of the ever-present tax burden.

But as people moved to cities, they had to pay rent. Buy gas or coal and, eventually, electricity. Water and trash collection are pretty essential, too. But at some point, everyone realized that being in a position to bill you monthly is a good idea. Now we pay for the internet, movie subscriptions, meal plans, alarm monitoring, shopping clubs, cell phones, spa memberships. Soon we might be paying a monthly fee for our robots, too.

Rent To (Not) Own

In industry, this is a common occurrence. You often don’t buy a robot arm or similar device. That, after all, is a capital expense, and most tax codes require you to count it as an asset that slowly depreciates. Instead, you hire a robot from a service provider. Not only does that make it a pure expense, but the provider worries about software, repairs, and all that.

But at home, it is different. There’s no tax advantage in most places between owning a car and leasing it. Yet vendors want to adopt a rent-a-robot strategy. Case in point: a startup named Matician wants you to sign up for a robotic vacuum. For $125 a month, you get a super smart robot vacuum. You could, of course, buy a Roomba, but — according to Matician — the Matic robot uses computer vision to map your house and automatically finds messes. You can also voice command it to clean up areas. It also avoids wire and furniture. They didn’t mention if it can avoid presents left by your pets or not. It will avoid pets and kids, though.

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Open-Source AR Hack Chat

Join us on Wednesday, May 31 at noon Pacific for the Open-Source AR Hack Chat with Raj Nakaraja!

We may live in a soup of electromagnetic waves that range in wavelength from the diameter of Jupiter down to a fraction of the radius of a hydrogen atom, but our eyeballs have evolved to only let us sense a tiny slice of that spectrum. That’s too bad, really, because there’s a lot going on in the rest of the spectrum that could potentially inform our ROYGBIV-centric view of the world. Think of the possibilities of being able to see UV the way an insect does, or being able to watch the radiation pattern of an antenna and make adjustments on the fly. Sounds like a job for augmented reality.

join-hack-chatIf seeing the world with different eyes sounds as cool to you as it does to us, you won’t want to miss Raj Nakaraja’s stop by the Hack Chat. Raj is head of engineering at Brilliant Labs, an augmented reality company that’s looking to bring AR into the mainstream. They’ve got some cool ideas about AR, and we’re going to take the opportunity to talk to Raj about open-source AR in general, Brilliant’s products specifically, and how AR can be incorporated into not only our projects, but into our lives as well.

Our Hack Chats are live community events in the Hack Chat group messaging. This week we’ll be sitting down on Wednesday, May 31 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.