Author: Gerrit Coetzee

476 Articles

DIY Scalar Network Analyzer

December 25, 2019 by 1 Comment

[Steven Merrifield] built his own Scalar Network Analyzer and it’s a beauty! [Steve]’s SNA has a digital pinout matching a Raspberry Pi, but any GPIO could be used to operate the device and retrieve the data from the ADC. The design is based around a few tried and true chips from Analog Devices. He’s taken some care to design it to be nice and accurate which is why he’s limited it to 1kHz to 30Mhz. We think it’s quite a fetching board once the shielding is in place.

We’ve covered network analyzers and their usefulness before. If you want to know how, for example, a mystery capacitor from your junk bin will respond to certain frequencies, a network analyzer could tell you. We’ve even taken a stab at hacking together our own.

There is more documentation on his website as well as some additional example curves. The board is easily ordered from OSHpark and the source code is available for review.

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Listen To Your Feet, They Have A Lot To Tell You

December 22, 2019 by 8 Comments

[Umar Qattan] is in tune with his sole and is trying hard to listen to what it has to say.

At a low level, [Umar] is building an insole with an array of force sensors in it. These sensors are affixed to a flexible PCB which is placed in a user’s shoe. A circuit containing a ESP32, IMU, and haptic feedback unit measure the sensors and send data back to a phone or a laptop.

What’s most interesting are the possibilities opened by the data he hopes to collect. The first application he proposes is AR/VR input. The feedback from the user’s feet plus the haptics could provide all sorts of interesting interaction. Another application is dynamically measuring a user’s gait throughout the day and exercise. People could save themselves a lot of knee pain with something like this.

[Umar] also proposes that an insert like this could record a user’s weight throughout the day. Using the data on the weight fluctuation, it should be possible to calculate someone’s metabolism and hydration from this data.

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Building A Limitless VR Desktop

December 21, 2019 by 44 Comments

[Gabor Horvath] thinks even two monitors is too little space to really lay out his windows properly. That’s why he’s building a VR Desktop straight out of our deepest cyberpunk fantasies.

The software runs on Windows and Android at the moment. The user can put up multiple windows in a sphere around them. As their head moves, the window directly in front grows in focus.  Imagine how many stack overflow windows you could have open at the same time!

Another exciting possibility is that the digital work-spaces can be shared among multiple users. Pair programming isn’t so bad, and now the possibility of doing it effectively while remote seems a little more possible. Even pair CAD might be possible depending on how its done. Imagine sharing your personal CAD session on another user’s screen and seeing theirs beside yours, allowing for simultaneous design.

Overall it’s a very cool tech demo that could turn into something more. It makes us wonder how long it is before tech workers on their way to lunch are marked by a telltale red circle on their face.

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DIY Lawnmower Doesn’t Cut Grass Short

December 21, 2019 by 81 Comments

[nodemcu12ecanada] is serious about saving water, which is why they built this strange lawnmower that can cut grass taller.

Short lawns are one of those clever marketing victories, like convincing people to eat a lot of sugar, that’s been doing more harm than good ever since the victory was won. Short grass is weak grass, with shallow roots, weakness to weeds, and a lot of water requirement. On top of that the grass is always in a state of panic so it grows extra fast to get to a more “natural” height. It’s great if you want to sell fertilizer, seeds, and lawnmowers. Maybe not so great for the environment.

Most lawnmowers can’t even be set high enough for healthy grass so [nodemcu12ecanada] took three electric weed whackers and bolted them to an angle iron frame. It has a lot of advantages. It’s light. You don’t need to sharpen a blade. It’s quiet. It’s electric. It’s strange appearance will scare your neighbors off from borrowing any of your tools. We love it!

Interactive Core Memory Shield Helps Explains The Past

December 19, 2019 by 9 Comments

[Andy Geppert] sends in his incredibly clever interactive core memory shield. 

In a great display of one hacker’s work being the base for another’s, [Andy] started out with [Jussi Kilpelainen]’s core memory shield for Arduino.  As he was playing with the shield he had a desire to “see” the core memory flipping and got the idea to add an LED matrix aligned behind the individual cores.

The first iteration worked, but it only showed the state that the Arduino believed the core memory to be in. What he really wanted was a live read on the actual state. He realized that an Adafruit Featherwing 8×8 matrix display also fits behind the core memory. Now the LEDs update based on the read state of the core memory. This allows him to flip the individual bits with a magnetic stylus and see the result. Very cool.

You can see a video of it working after the break.

Continue reading “Interactive Core Memory Shield Helps Explains The Past” →

A Box With A Pocket Sized Boom

December 19, 2019 by 7 Comments

[Discreet Electronics Guy] sends in his very pocket sized boom box.

One thing we love about [Discreet Electronics Guy]’s projects is how they really showcase that a cool hack is possible without access to 3D printers, overnight PCB services, and other luxuries. Everything in this board is hand made by electronics standards. The board is etched, the vias are wires, and even the case seems to be a modified plastic mint container.

The boombox itself uses an ATiny85 at its core which plays .wav files from an SD card. This is routed through an audio amp which powers two small speakers. We love the volume knob being a board mount potentiometer. The device even features its own small LiON battery pack. If you don’t want to enjoy the deep sound of the two small speakers there’s a headphone jack.

He’s got a great write-up on the circuit design on his website and you can see a video of him presenting the project here or after the break.

Continue reading “A Box With A Pocket Sized Boom” →

Replace Your Smartphone With These Arcane Amulets

December 19, 2019 by 17 Comments

It’s hard not to feel the constant pull on our limited attention from the very interesting rectangles in our pockets and packs. [Antoine Pintout] is fighting against it with three interesting pendants.

The three objects each have functions. Sablier, tells time, but rather than giving the numerals it vibrates on a set interval to give a relative sense of the passage. Boussole is a compass like device which doesn’t tell the cardinal directions. Instead it tells you which way to go in order to get to a pre-set location. The last, Sifflet, is a pager, but rather than sending a text it plays a melody reflecting the sender’s mood.

We love the look of the objects. The circuits are beautifully laid out and showcased in well machined brass cases. Small details abound; in Sifflet for example, the coil antenna is symmetrically presented with its own cutout in the board. Laying out a board is hard enough, but taking this much care in component placement easily doubles the time.

All the files and models are available,  though we’re not sure we possess the craftsmanship to reproduce these to the same standard.

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