Building A Top-Notch Electret Microphone

November 2, 2020 by Zoe Skyforest 25 Comments

Electret microphones are capable of high-quality output, and are prized for their smooth frequency response. However, unlike other types, they can’t simply be plugged directly into a mixing desk. Instead, they require special high-impedence circuitry to extract the audio signal for recording. [DJJules] is a big fan of these microphones, and decided to build a high-quality, easy to use circuit that he has shared with the community.

The goal of the project was to create a circuit to match the TSB2555B electret capsule that could be used with phantom power, and that could be built with easily obtainable parts. [DJJules] had used FETs in the past, but grew tired of routinely having to hunt for obsolete parts. Instead, this design relies on a dual OPA1642 op-amp, with its low quiescent current meaning it’s perfect for running off phantom power. This means the microphone needs no batteries, and using a dual op-amp enables the circuit to properly drive a balanced audio connection.

The circuit is designed to fit inside a common BM700 or BM800 microphone body, and the PCB can be ordered from PCBWay for those interested in building their own. There’s also a saddle on Shapeways that’s designed to neatly mount the electret capsule within the housing.

The final results are impressive, and this project would make a great entry into the DIY microphone space for anyone eager to start building their own gear. Of course, there are simpler builds if you’re looking for an easier way to get started. Video after the break.

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Robot Sink Helps With The Dishes

November 2, 2020 by Zoe Skyforest 16 Comments

The humble kitchen sink has remained relatively unchanged over the last century. While there are now fancier mixing taps and sleeker fittings available, for most of us, there’s a nozzle that squirts water of varying temperature, and a tub in which to soak dishes. Of course, this leaves plenty of room for improvement, as [Jake] found with his robot sink build.

The sink consists of a robotic nozzle, which he refers to as a “continuum manipulator”. In essence, it’s a nozzle that can be steered with a joystick to aim the flow of water throughout the sink. To move the nozzle, motors pull on steel cables attached to 3D printed collars fastened around the hose. Combined with an on/off switch for the water flow, the sink could be a useful assistive technology for those with disabilities, as demonstrated in the project’s demo video.

We could easily imagine such hardware being combined with a simple computer vision system to further automate the cleaning of dishes. The project actually serves as a proof of concept for work [Jake] is doing to explore 3D printing concrete with similar hardware, albeit scaled up to a more industrial level. We’ve featured similar technology before, too — in the form of a DIY tentacle build that’s perfect for Halloween. Video after the break.

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Big Workshop Clock Is 3D Printing Done Right

November 1, 2020 by Zoe Skyforest 7 Comments

Time is something uniquely important to humans, and they remain the only creatures on the planet to build devices to regularly track its progress. [Ivan Miranda] is one such creature, and built a giant 7-segment clock for his workshop that really ties the room together.

The clock is a testament to [Ivan]’s design skills in the 3D printed space. Taking advantage of his large format printer, each segment consists of a front panel, large single-piece diffuser, LED carrier, and backing plate. There are plenty of nice touches, from the interlocking ridges between each digit, to integral printed arrows on the inside that guide installation of the LED strips. Fit and finish approaches the level of a commercial product, a reward for [Ivan]’s years of practice in the field.

Electronically, an ESP8266 runs the show, synchronizing the time over its in-built WiFi connection. Each segment contains 9 WS2812B LEDs, wired up in a single long strip that’s addressed by the microcontroller. This means that the segments can be lit up to any color of the rainbow, though [Ivan] is a man who best appreciates the look of classic red.

[Ivan]’s long been a proponent of big 3D-printed builds — his tank-tracked electric skateboard is a particularly good example. Video after the break.

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Burning Your Own PS1 Modchip Is Easy

November 1, 2020 by Zoe Skyforest 18 Comments

The original Sony PlayStation came out just in time for CD piracy to really start taking off. Aware of this threat to sales, Sony engineers included a copy protection and region locking mechanism that placated executives and annoyed end-users alike. [MattKC] explores how this copy protection worked, and how you can burn your own modchip at home for just a few dollars.

Sony’s method of copy protection relied on steps taken during the manufacturing process, pressing a special groove into the game media that regular CD burners couldn’t replicate, a topic our own [Drew Littrell] has covered in depth. This groove contained a four letter code that could be read by the console, corresponding to the region in which the game was sold. The console would read this groove on startup, and check that the code in the game matched the code in the console before booting. Modchips circumvent this by injecting a spoof code into the console that matches the local region, regardless of what is read off the disc. This has the effect of both allowing users to run bootleg CD-Rs, homebrew code, as well as games from other regions.

Today, we’re blessed with the Internet and cheap hardware. As [MattKC] demonstrates, it’s no longer necessary to mail-order a chip from a dodgy ad in the back of a games magazine; instead, one can download source code and flash it to a commodity PIC microcontroller for just a few bucks. With the chip soldered in to the relevant points of the PS1’s motherboard, you’re good to go.

As far as console modding goes, the PS1 is a great platform to start with — simple to work on, and also the best selling console of all time, so the stakes are low if you mess up. Video after the break. Continue reading “Burning Your Own PS1 Modchip Is Easy” →

Fuel Cell Drone Aims For Extended Flight Times

October 31, 2020 by Zoe Skyforest 15 Comments

The RC world was changed forever by the development of the lithium-polymer battery. No longer did models have to rely on expensive, complicated combustion engines for good performance. However, batteries still lack the energy density of other fuels, and so flying times can be limited. Aiming to build a drone with impressively long endurance, [Игорь Негода] instead turned to hydrogen power.

The team fitted a power meter to the plane, aiming a camera at it to measure power draw during flight.

With a wingspan of five meters, and similar length, the build is necessarily large in order to carry the hydrogen tank and fuel cell that will eventually propel the plane, which uses a conventional brushless motor for propulsion. Weighing in at 6 kilograms, plenty of wing is needed to carry the heavy components aloft. Capable of putting out a maximum of 200W for many hours at a time, the team plans to use a booster battery to supply extra power for short bursts, such as during takeoff. Thus far, the plane has flown successfully on battery power, with work ongoing to solve handling issues and determine whether the platform can successfully fly on such low power.

We’re eager to see how the project develops, particularly in regards to loiter time. We can imagine having a few pilots on hand may be necessary with such a long flight time planned — other drones of similar design have already surpassed the 60-minute mark. Video after the break.

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Self-Driving RC Truck Is A Master’s Thesis In Cybernetics And Robotics

October 31, 2020 by Zoe Skyforest 7 Comments

RC cars are a fun pastime, but for many hackers, taking things to the next level involves making the cars drive themselves. For his Masters thesis, [Jon] did just that, building a self-driving robot truck that confidently cruises the floor of his laboratory.

The truck is based on a 1/14th scale Tamiya chassis, and had been fitted out by a prior group with an inductive charging system. On top of this platform, [Jon] added a Jetson TX2 to act as the brains of the system, hooking it up with a Slamtec RPLIDAR scanner to map its surrounding environment. There’s also a Teensy microcontroller onboard which handles synthesizing PWM signals for the radio control hardware that drives the truck, and a Logitech webcam up front for machine vision. The truck is capable of operating in a variety of modes, from full manual operation, to driving based on LIDAR mapping or with an AI controlling the truck based on camera data. The truck is programmed to drive a route including an inductive charging pad so it can keep its power levels up without human intervention.

It’s a great blueprint for a self-driving system, and [Jon]’s thesis goes into great detail on how everything works at the base level (available on this page as a 67 MB PDF). His Code is on Github for the curious. We’ve seen similar projects before too, like this robot that navigates its builder’s house using LIDAR. Video after the break.

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School Project Turns Plastic Waste Into Bricks

October 31, 2020 by Zoe Skyforest 66 Comments

Many plastics are, in theory at least, highly recyclable. Unfortunately, in reality, most plastic ends up as waste instead, harming the environment and providing no ongoing value to society. Wanting to investigate possible ways to repurpose this material, [Rehaan33] built a rig to create bricks out of waste plastic for a school project.

The aim of the project is to take waste plastic, in this case high-impact polystyrene, and reform it into a brick that could be used as a low-cost building material. The material is shredded, before being packed into a steel mould and heated to 270 degrees in an oven. As polystyrene is a thermoplastic, it can readily be heated in this way for reforming without harming the material’s properties. Once heated, the mould is placed into the press rig, which uses parts of an old drill press to force down a steel plate, helping shape the final form of the brick.

While you’re unlikely to see old soda bottles used to build a skyscraper in New York any time soon, such techniques could be a good way to help eliminate plastic waste in impoverished areas and stem the flow of plastic into the world’s oceans. The project served as a useful learning experience, allowing [Rehaan33] to pick up skills in metalworking, machine design, and working with thermoplastics. Recycling plastics is a key area of interest for many, particularly in the 3D printing space, with many exploring ways to reuse thermoplastics in more efficient ways. If you’ve got your own project turning waste plastics into useful material, be sure to let us know!