OpenMV Cam H7: the Open Source MicroPython Powered Machine Vision Camera

via Open Electronics

The New OpenMV Cam H7 is an upgrade of the previous OpenMV Cam M7, replacing the STMicro STM32F7 micro-controller by a more powerful STM32H7 MCU clocked at up to 400 MHz and introducing removable camera modules for thermal vision and global shutter support. The OpenMv Cam aims at becoming a super powerful Arduino with a camera […]

Glowing mercury thyratrons: Inside a 1940s Teletype switching power supply

via Dangerous Prototypes


Ken Shirriff take a look inside a bulky DC power supply REC-30 rectifier, how it works and contrast it with a MacBook power supply:

We recently started restoring a Teletype Model 19, a Navy communication system introduced in the 1940s.14 This Teletype was powered by a bulky DC power supply called the “REC-30 rectifier”. The power supply uses special mercury-vapor thyratron tubes, which give off an eerie blue glow in operation, as you can see below.
The power supply is interesting, since it is an early switching power supply. (I realize it’s controversial to call this a switching power supply, but I don’t see a good reason to exclude it.) While switching power supplies are ubiquitous now (due to cheap high-voltage transistors), they were unusual in the 1940s. The REC-30 is very large—over 100 pounds—compared to about 10 ounces for a MacBook power supply, demonstrating the amazing improvements in power supplies since the 1940s. In this blog post, I take a look inside the power supply, discuss how it works, and contrast it with a MacBook power supply.

See the full post on Ken Shirriff ‘s blog.

DIY a Tiny Lego Drone With a 6-Axis Gyro & Auto-Stabilization

via Open Electronics these days has a deal on the Force Flyers DIY Building Block Drone, so you can save 14% off the normal price. It could be an opportunity to start “playing” with drones, if you haven’t already. For $42.99 you can choose between different version of this drone: Space, Army, Fire Fighter and Police. Channel your inner […]

This Pinball Game Doesn’t Come In A Box… It Is The Box


Loved these the first time I saw them @makerfaire NY a few years ago.  Recent iterations even better.

via Hackaday

Pinball still has that bit of magic that makes it stand out from first person shooters or those screen mashers eating up your time on the bus. The secret sauce is that sense of movement and feedback, and the loss of control as the ball makes its way through the play field under the power of gravity. Of course the real problem is finding a pinball machine. Pinbox 3000 is swooping in to fix that in a creative way. It’s a cardboard pinball machine that you build and decorate yourself.

We ran into them at Maker Faire New York over the weekend and the booth was packed with kids and adults all mashing flippers to keep a marble in play. The kit comes as flat-pack cardboard already scored and printed with guides for assembly which takes about an hour.

The design is quite clever, with materials limited to just cardboard, rubber bands, and a few plastic rivets. Both the plunger that launches the pinball and the flippers are surprisingly robust. They stand up to a lot of force and from the models on display it seems the friction points of cardboard-on-cardboard are the issue, rather than mechanisms buckling under the force exerted by the player.

When first assembled the playfield is blank. That didn’t stop the fun for this set of kits stacked back to back for player vs. player action. There’s a hole at the top of playfields which makes this feel a bit like playing Pong in real life. However, where the kit really shines is in customizing your own game. In effect you’re setting up the most creative marble run you can imagine. This task was well demonstrated with cardboard, molded plastic packaging (which is normally landfill) cleverly placed, plus some noisemakers and lighting effects. The company has been working to gather up inspiration and examples for building out the machines. We love the multiple layers of engagement rolled into Pinbox, from building the stock kit, to fleshing out a playfield, and even to adding your own electronics for things like audio effects.

Check out the video below to see the fun being had at the Maker Faire booth.


App note: Extending I2C communication distance with the DS28E17

via Dangerous Prototypes


App note from Maxim integrated about alternative method to extend I2C bus. Link here (PDF)

Systems are increasingly requiring greater distances for I2C buses. This article explains how the DS28E17 can be used to extend the distance of I2C devices while decreasing cost.

There Are Multiple Ways To Gesture With This Serpentine Sensor


via Hackaday

Serpentine is a gesture sensor that’s the equivalent of a membrane potentiometer, flex and stretch sensor, and more.  It’s self-powering and can be used in wearable hacks such as the necklace shown in the banner image though we’re thinking more along the lines of the lanyard for Hackaday conference badges, adding one more level of hackability. It’s a great way to send signals without anyone else knowing you’re doing it and it’s easy to make.

Collecting analog data from Serpentine

Serpentine is the core of a research project by a group of researchers including [fereshteh] of Georgia Tech, Atlanta. The sensor is a tube made of a silicone rubber and PDMS (a silicone elastomer) core with a copper coil wrapped around it, followed by more of the silicone mix, a coil of silver-coated nylon thread, and a final layer of the silicone mix. Full instructions for making it are on their page.

There are three general interactions you can have with the tube-shaped sensor: radial, longitudinal, and tangential. Doing various combinations of these three results in a surprising variety of gestures such as tap, press, slide, twist, stretch, bend, and rotate. Those gestures result in signals across the copper and silver-coated nylon electrodes. The signals pass through an amplifier circuit which uses WiFi to send them on to a laptop where signal processing distinguishes between the gestures. It recognizes the different ones with around 90% accuracy. The video below demonstrates the training step followed by testing.

Serpentine works as a result of the triboelectric nanogenerator (TENG) phenomenon, a mix of the triboelectric effect and electrostatic induction but fabrics can be made which use other effects too. One example is this fabric keyboard and theremin which works in part using the piezoelectric effect.


Fixing An IBM 1401 Computer To Get It Printing Again

via Hackaday

The IBM 1401 is a classic computer which IBM marketed throughout the 1960s, late enough for it to have used transistors rather than vacuum tubes, which is probably a good thing for this story. For small businesses, it was often used as their main data processing machine along with the 1403 printer. For larger businesses with mainframes, the 1401 was used to handle the slower peripherals such as that 1403 printer as well as card readers.

Broken germanium transistor
Broken germanium transistor

The Computer History Museum in Mountain View, CA has two working 1401s as well as at least one 1403 printer, and recently whenever the printer printed out a line, the computer would report a “print check” error. [Ken Shirriff] was among those who found and fixed the problem and he wrote up a detailed blog entry which takes us from the first test done to narrow down the problem, through IBM’s original logic diagrams, until finally yanking out the suspect board and finding the culprit, a germanium transistor which likely failed due to corrosion and an emitter wire that doesn’t look solidly connected. How do they know that? In the typical [Ken]-and-company style which we love, they opened up the transistor and looked at it under a microscope. We get the feeling that if they could have dug even deeper then they would have.

If you’re unfamiliar with the work of this team who maintain the machines at the museum, you’ll want to read up on how they recently got a 1401 to run FORTRAN II code.