Author: Gerrit Coetzee

476 Articles

Detecting Water Before It’s Too Late

November 14, 2019 by 25 Comments

[mcu_nerd] is like any engineer, which is why his problem of an occasionally leaky water heater sure looks like a research project with no end in sight. Sure there’s probably a commercial product out there that can be had for half the cost and a few clicks of the mouse, but what’s the point in actually solving the problem?

His log starts with research into detecting low battery voltages. Then it was a quick exploration in designing low-power circuits. When the Flexible PCB contest came along, he realized that there was a chance to design a better electrode, and he ended up winning one of the vouchers; which is where he’s at now.

It’s definitely a work in progress, and if anything it’s just a quick five minute read and an opportunity to commiserate with another wayward soul. We do like his clever use of a tealite candle tin as both the second electrode and case for his water detection circuit. There are also some KiCad files and code.

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Watch A 3D Printer Get Designed From The Ground Up

November 10, 2019 by 15 Comments

Too often when you see a build video, you only get to see the final product. Even if there’s footage of the build itself, it’s usually only the highlights as a major component is completed. But thankfully that’s not the case with the “V-Baby” CoreXY 3D printer that [Roy Berntsen] has been working on.

Watching through his playlist of videos, you’re able to see him tackle his various design goals. For example he’d like the final design to be both machinable and printable, which is possible, but it certainly adds complexity and time. He also transitions from a triangular base to a rectangular one at some point. These decisions, and the reasons behind them, are all documented and discussed.

Towards the end of the series we can see the final testing and torturing process as he ramps up to a final design release. This should definitely demystify the process for anyone attempting their first 3D printer design from scratch.

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Use Your Earbud’s Media Controls On Your Laptop With This Useful Dongle

November 9, 2019 by 3 Comments

[David] sends in his very nicely designed “Thumpware Media Controller” that lets your mobile phone headphones control the media playback on your PC.

We realize that some PCs have support for the extra pins on cellphone earbuds, but at least some of us have experienced the frustration (however small) of habitually reaching up to touch the media controls on our earbuds only to hear the forlorn click of an inactive-button. This solves that, assuming you’re still holding on to those 3.5mm headphones, at least.

The media controls are intercepted by a PIC16 and a small board splits and interprets the signals into a male 3.5mm and a USB port. What really impressed us is the professional-looking design and enclosure. A lot of care was taken to plan out the wiring, assembly, and strain relief. Overall it’s a pleasure to look at.

All the files are available, so with a bit of soldering, hacking, and careful sanding someone could put together a professional looking dongle for their own set-up.

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UECG – A Very Small Wearable ECG

November 8, 2019 by 16 Comments

[Ultimate Robotics] has been working on designing and producing an extremely small ECG that can stream data real time.

Typical electrocardiogram equipment is bulky: miniaturization doesn’t do much for a hospital where optimizations tend to lean towards, durability, longevity, and ease of use. Usually a bunch of leads are strung between a conductive pad and an analog front end and display which interprets the data; very clearly identifying the patient as a subject for measurement.

uECG puts all this in a finger sized package. It’s no surprise that this got our attention at Maker Faire Rome and that they’re one of the Hackaday Prize Finalists. The battery, micro controller, and sampling circuitry are all nearly packed onto the board. The user has the option of streaming through BLE at 125 Hz or using a radio transceiver for 1 kHz of data. Even transmitting at these sample rates and filtering the signal of unwanted noise the device draws less than 10 mA.

The files to make the device are all on their page. Though they are planning to produce the boards in a small run which should be the best way to acquire one and start experimenting with this interesting data.

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Bobble-Bot Teaches Modern Real-Time Robot Control

November 7, 2019 by 7 Comments

Bobble-Bot uses the standard inverted pendulum problem to teach modern robotic control using a Raspberry Pi, RT-Linux, and ROS.

We’re really impressed by the polish and design effort put into this project, and it’s no surprise that it’s a finalist in the 2019 Hackaday Prize. Bobble-Bot is a top heavy bot sitting on two BLDC motors. The brains of the operation is a Raspberry Pi running real-time Linux and ROS. This allows the robot to respond in a predictable manner to its inputs, and also allows for more control over thread priority than a regular kernel. In the past we’ve seen these inverted pendulum bots mostly being run on micro-controllers for just this reason, so it’s cool to see it make the jump to Linux.

Mechanically the bot can be printed on any consumer grade printer and assembled. We really appreciate the small details like making sure one screw size could be used to assemble the entire bot, eliminating the need for multiple tools.

They also have a simulator, and the bot’s software was built inside of that. It was a big moment when the real-world behavior finally matched the simulated performance. In fact, if you’re interested in the Bobble-Bot, you can try it out in simulation before committing to building the whole thing.

This project seems like a fun build for any hacker. We would have loved to have a project as polished and up-to-date as this one when we were learning controls in university. Video introducing it after the break.

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The Open Source Smart Home

November 6, 2019 by 27 Comments

[Tijmen Schep] sends in his project, Candle Smart Home, which is an exhibit of 12 smart home devices which are designed around the concepts of ownership, open source, and privacy.

The central controller runs on a Raspberry Pi which is running Mozilla’s new smart home operating system. Each individual device is Arduino based, and when you click through on the site you get a well designed graphic explaining how to build each device.

It’s also fun to see how many people worked together on this project and added their own flair. Whether it’s a unique covering for the devices or a toggle switch that can toggle itself there’s quite a few personal touches.

As anyone who’s had the sneaking suspicion that Jeff Bezos was listening in to their conversations, we get the need for this. We also love how approachable it makes hacking your own hardware. What are your thoughts?

Giving Sight To The Blind With A Wave Of The Hand

November 6, 2019 by 1 Comment

[Jakob Kilian] is working on a glove that he hopes will let the blind “see” their surroundings.

One of the most fascinating examples of the human brain’s plasticity is in its ability to map one sense to another. Some people, for example, report being able to see sound, giving them a supernatural ability to distinguish tones. This effect has also been observed in the visually impaired. There are experiments where grids of electrodes were placed on the tongue or mechanical actuators were placed on the lower back. The signals from a camera were fed into these grids and translated in to shocks or movement. The interesting effect is that the users quickly learned to distinguish objects from this low resolution input. As they continued to use these devices they actually reported seeing the objects as their visual centers took over interpreting this input.

Most of these projects are quite bulky and the usual mess you’d expect from a university laboratory. [Jakob]’s project appears to trend to a much more user-friendly product. A grid of haptics are placed on the back of the user’s hand along with a depth camera. Not only is it somewhat unobtrusive, the back of the hand is very sensitive to touch and the camera is in a prime position to be positioned for a look around the world.

[Jakob] admits that, as an interaction designer, his hardware hacking skills are still growing. To us, the polish and thought that went into this is already quite impressive, so it’s no wonder he’s one of the Hackaday Prize Finalists.

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