DIY Bass Drum Microphone Uses Woofer Cone As Diaphragm

Anyone into audio recording knows that recording drums is a serious pain. Mic setup and positioning can make or break a recording session. One particular hurdle is getting a great sound out of the bass drum. To overcome this, [Mike] has built a microphone using an 8″ woofer in an attempt to capture the low-end frequencies of his bass drum. Using a speaker as a microphone isn’t a new idea and these large diaphragm bass drum mics have taken commercial form as the DW Moon Mic and the now-discontinued Yamaha SubKick.

The project is actually quite simple. The speaker’s positive terminal is connected to Pin 2 of a 3-pin XLR microphone connector. The speaker’s negative terminal is connected to the connector’s Pin 1. [Mike] made a bracket to connect the woofer to a mic stand, which in turn was cut down to position the woofer at bass drum height. The setup is then plugged into a mixer or pre-amp just like any other regular microphone.

[Mike] has since made some changes to his mic configuration. It was putting out way too hot of a signal to the preamp so he added an attenuation circuit between the speaker and XLR connector. Next, he came across an old 10″ tom shell and decided to transplant his speaker-microphone from the open-air metal rack to the aesthetically pleasing drum shell. Check out [Mike’s] project page for some before and after audio samples.

Self Powered Camera Powers Itself

Cameras sense light to create images, and solar cells turn light into energy. Why not mash the two together and create a self-powered camera?

The Computer Vision Laboratory at Columbia built this unique camera, which harvests power from its photodiode sensors. These photodiodes also act as an array of pixels that can recover an image. The result is a black and white video camera that needs no external power supply.

The energy harvester circuit charges up a supercap that provides power to the system. The frame rate of the camera is limited by the energy that can be harvested: higher frame rates require more juice. For this reason, the team developed an algorithm that varies the frame rate based on available energy.

The MC13226V microcontroller that was used for this build features an internal 2.4 GHz radio. The group mentions wireless functionality as a possibility feature in the future, which would make for a completely untethered, battery free camera.

RetroPie Meets Game Gear, Again

If you’re a fan of video game systems of yesteryear then you are probably familiar with RetroPie. For those who aren’t, RetorPie is a collection of software and video game emulators that can run on a Raspberry Pi. The package makes it easy to get your fix of old games without having to own a bunch of consoles or loose your breath blowing on cartridges.

[brooksyx] already had a broken Game Gear, Raspberry Pi and a 4.3 inch LCD screen kicking around so he thought it would be a good idea to put them together into a handheld RetroPie. Clearly, the new screen was not going to fit in the old screen’s place. The Game Gear’s case was cut and the bezel from the new LCD screen was epoxied in place, gaps filled and finally sanded.

RetroPie Game Gear

 

The screen is not the only modifications done to the case. Down on the bottom right of the case front [brooksyx] added 4 buttons for the N64 C-buttons. Out back the battery compartments and cartridge slot were filled in.

This project isn’t done yet and we are excited to see how it comes out. If you’re digging this RetroPie portable, you may like this Game Gear with an unmodified case or this large-screened Game Boy.

VCF East X: The Quarternet Steering Committee

Today was the first day of the Vintage Computer Festival East X. As is the tradition, the first day was packed with talks and classes about various retrocomputing ephemera, with this year featuring a great talk from [David Riley] about 8-bit computer music, a class on system architecture from our own [Bil Herd] (video coming soon), and a talk about vintage teletypes. One of these talks was about creating new hardware: [Jim Brain]’s steering committee on a networking solution for vintage microcontrollers. It’s called Quarternet: a two-bit solution for an eight bit world.

While minicomputers are easily networkable, designed around multi-user operating systems, and have the hardware for a lot of networking hardware, 8-bit micros are the exact opposite. That doesn’t mean 8-bitters don’t have networking; you can get an Ethernet cart for a C64, and just about everything can connect to a BBS. [Jim]’s talk was about whittling down the use cases for the Quarternet to something that could be implemented easily, but still give the most capability.

During the talk, the audience settled on using a serial connection from the micro to the outside world; this makes sense, as everything has a serial port. A ‘lightweight API’ was suggested to take up the software side of the problem, but there wasn’t much agreement over what that API would actually do.

[Jim]’s idea is for a box that plugs into the serial port of any old microcomputer and would connect to the Internet somehow. Ethernet, WiFi, or even a modem isn’t out of the question here. That takes care of connecting to the Internet, but there’s also the question of the cooler side of networking – network drives, file sharing, and the like.

For this, [Jim] is imagining a box with a serial port on one end, and a network port on the other. In the middle would be a cartridge slot for any hardware imaginable. If you want to plug in an Apple II disk drive, just insert the right cartridge and you’re good to go. If you need network access to a Commodore 1541 drive, just insert another cartridge, and it’ll just work.

It’s an interesting idea, but [Jim] is really interested in getting even more feedback for a networking system for old microcomputers. If you have any ideas, leave a note for him in the comments.

Energia Multitasking uses RTOS on MSP432

We keep wondering where the Arduino world is headed with the hardware getting more and more powerful. If the IDE doesn’t keep up what’s the point? Now we have at least one answer to that problem. Energia is the Arduino-like-framework for Texas Instruments based boards. They just came out with a multitasking system built into Energia targeted at the ARM Cortex-M4F based MSP432 Launchpad which we covered a few weeks back.

The announcement post gives a couple of examples of uses for multitasking. The simplest is blinking LEDs at different rates. If you wanted to do this closer to the metal you’re talking about multiple timers, or multiple compares on a single timer, perhaps a interrupt-driven-system-tick that has a high enough resolution for a wide range of your blinking needs. But these are not always easy to set up unless you are intimately comfortable with this particular architecture. The Energia multitasking will handle this for you. It’s upon the TI Real Time Operating System (TI-RTOS) but wraped in the familiar IDE.

The UI divorces you from thinking about the hardware at all. You simply launch a new tab and start coding as if you’re using a completely separate piece of hardware. The announcement post linked above mentions that these Sketches are running “in parallel”. Well… we know it’s not a multi-core system like the Propeller but we’ll let it slide. It is certainly easier than building your own scheduler for this type of hardware.

[Thanks MycoWx]

“Easy Bake” Vacuformer

One of our favorite things about Hackerspaces is people tend to spend a lot of time building tools, or repairing/upgrading older ones. This is a case of the former. The vacuum former.

[Adam] wrote in to tell us about this vacuum forming machine which he and few other members built for FizzPOP, a hackerspace in Birmingham, England. The device is used to suck hot sagging plastic around a mold. This is accomplished in two parts, the vacuum table and the heating mechanism to put the sheet of plastic into that sagging state.

vacuum-forming-signThe vacuum part of these tools has been easy to DIY for a long time. Pegboard makes for a very good table surface, with some type of vacuum motor (usually a shopvac or two) in an enclosure below the surface. This design adheres to that common formula.

On the other hand, the heating mechanism is more difficult to solve. The plastic is unwieldy and fragile when hot so a frame is very common. Following the example of commercially available models, the FizzPOP crew built a frame that slides along four vertical rails (envision table legs) extending above the vacuum surface. These legs also hold up the heating element. Often this is a nichrome wire array, but not this time. They went with an array of 70 halogen bulbs in a 10×7 orientation. A PCB was milled for each, with a system of bus-bars connecting them all. The trial run showed that the intensity of the bulbs made hotspots directly below each. But a bit more testing helped them solve the issue by keeping the frame further from the array in the heating phase.

The team’s 13-seconds of fame are found after the break. A black sheet of High-Impact Polystyrene (HIPS) is formed around a compilation of tools spelling out the name of the hackerspace.

Continue reading ““Easy Bake” Vacuformer”

You Betta’ Recognize the Aluminum Beverage Can

He’s back, [Bill Hammack] aka The Engineer Guy. He has a habit of revealing how the ordinary is extraordinary with a meticulous unveiling of all the engineering that goes into a thing. This time around it’s the aluminum beverage can. You might know it as a soda can, a beer can, or a salt-free air can. But we challenge you find someone who isn’t intimately familiar with these containers.

We know what you’re thinking: you already saw how these come into being on an episode of How It’s Made. You’re wrong. We saw that episode too. But just give [Bill] a few minutes of your time and he’ll suck you in for the rest of the episode. Now the die-forming of the base and side-wall, we’ll give it to you that you know what that’s all about. But then [Bill] busts into the history of these containers, citing the aluminum savings through reducing the top diameter of the can. He rounds it out with a celebration of the ingenuity of the modern “stay-on” tab which should make your glasses fall off with excitement.

If this is your first time hearing of The Engineer Guy you have a delightful weekend ahead of you. Binge watch his entire back cataolog! Our favorites include an analysis of a mechanical Fourier computer and the concepts involved in color anodization. We even read his book.

Continue reading “You Betta’ Recognize the Aluminum Beverage Can”