ADC For Raspi Without Using An ADC

July 13, 2014 by Will Sweatman 22 Comments

Schematic of ACD for a raspi

With all the amazing and wonderful things a Raspberry Pi can do, it is sorely lacking a dedicated ADC chip. Sure, you can wire up an ADC via SPI or even I2C with a little work, but still. It would be nice to have access to an Analog to Digital converter without having to go through the trouble. Fortunately, [Hussam] has figured out a way to do just this.

Using a comparator, two resistors, a single capacitor and a few lines of code, [Hussam] managed to get an active ADC working on his Raspberry Pi. He’s using the PWM1 and a passive RC filter to make a DAC. He then uses the comparator along with a ‘ successive approximation algorithm’ to complete the ADC.

[Hussam] mentions that the hack is not new, and this technique has been used before for microcrotrollers that lack a built-in ADC. But we are still impressed with his attention to detail in describing how to do this on a Raspi. Be sure to check out the link for full details, code, and an awesome description on how his algorithm works.

Introducing The Raspberry Pi B+

July 13, 2014 by Brian Benchoff 208 Comments

It looks like Element 14 screwed up a single shipment, because some lucky soul just received an unreleased model of Raspberry Pi. If you can believe the silkscreen, it’s called the Raspberry Pi Model B+, and while we have no idea what the chipset is, the layout and peripherals look pretty cool.

From the looks of it, this new board features four USB ports, a new, 40-pin GPIO header, and more screw holes that will allow you to secure this to anything. The analog video out is gone, and the SD card connector – a weak point of the original design – might be replaced with a microSD connector. Oh, every Raspi case that has ever been made? They won’t work.

Without booting this Raspi B+ there’s no way of knowing what the chipset is on this new board. The smart money is on the entire SOC being the same: basically, what you’re looking at is the same as a Raspberry Pi Model B, only with a few more ports.

There is no clue when these improved Raspis will be available, but the word “soon™” will probably appear on the Raspberry Pi blog shortly.

Thanks [John] for the tip.

EDIT: [feuerrot] is smarter than me and mirrored all the images in an imgur album.

Proper Debugging For Energia Sketches

July 13, 2014 by Eric Evenchick 10 Comments

Energia is a tool that brings the Arduino and Wiring framework to Texas Instruments’ MSP430 microcontrollers and the MSP430 Launchpad development board. This allows for easy development in an Arduino-like environment while targeting a different microcontroller family.

One problem with Energia and Arduino is the difficulty of debugging. Usually, we’re stuck putting a Serial.println(); and watching the serial port to trace what our program is doing. Other options include blinking LEDs, or using external displays.

Code Composer Studio, TI’s official development tool, allows for line-by-line debugging of applications. You can set breakpoints, watch the value of variables, and step through an application one instruction at a time.

The good news is that the latest version of Code Composer Studio supports importing Energia sketches. Once imported, you can step through the code and easily debug your application. This is a huge help to people developing more complex software using Energia, such as libraries.

TI gives us an overview of the new feature in a video after the break.

[Thanks to Adrian for the tip!]

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A Fully Mechanical 3D Printer Is Mind Blowing

July 13, 2014 by James Hobson 60 Comments

mechanical 3d printer

It’s been a while since we’ve been seriously impressed with a project like this one. [Daniël de Bruin], a student at the Art Academy in Utrecht has just put the final touches on his mechanical 3D printer.

That’s right. Mechanical.

No computers, no motors, just the power of gravity. It could have been built 100 years ago.

The machine uses a 15kg weight to power the mechanism — it does need to be reset during the print, but that’s a small price to pay for this kind of mechanical automation.

He uses a type of clay in a paste extruder that slowly deposits the material on the build platform. To program the machine, there is a small guiding mechanism that follows the contour of a bent aluminum wire. This allows you to make any number of symmetrical and circular objects.

[Daniël] says he was inspired to build this machine because he loves 3D printing — but at the same time, he feels like it’s kind of like cheating. Beyond pressing the print button, there’s no real human interaction.

I love technology but how can I reclaim ownership of my work? Perhaps by building the machine that produces the work. Perhaps by physically powering the machine, which I built, that produces the work. in hopes of rediscovering the sense of having created something, I create.

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Pi Musicbox 0.5 Released

July 13, 2014 by Eric Evenchick 4 Comments

Have an extra Raspberry Pi kicking around? Pi MusicBox provides a way to quickly turn it into a standalone streaming device that can fetch music from tons of sources. The latest release of Pi MusicBox adds a bunch of new features.

We took a look at this software over a year ago, and noted that it made streaming Spotify easy, and had support for controlling tracks using Music Player Daemon (MPD). The newest release supports AirPlay, DNLA, Google Music, SoundCloud, and several other music sources.

Since the analog audio output on the Pi isn’t great, Pi MusicBox includes support for a variety of USB sound cards. It’s also possible to use the HDMI port for digital audio output, which can be connected into your home theatre system.

If you want to build a standalone music device, this looks like a great place to start. The user community has built a variety of projects that run this software, which are featured on the Pi MusicBox homepage.

Independent Wheel Drive R/C Car

July 12, 2014 by Adam Fabio 30 Comments

4wdRcCar

The picture above looks like a standard four-wheel drive (4WD) touring car. As one looks closer, a few strange things start to pop out. Where’s the motor? 4 electronic speed controls? What’s going on here? [HammerFET] has created this independent drive R/C car (YouTube link) as a research platform for his control system. The car started off life as a standard Schumacher Mi5 1/10th scale Touring Car. [HammerFET] removed the entire drive system. The motor, differentials, belt drive, and ESC all made for quite a pile of discarded hardware.

He replaced the drive system with 4 Turnigy brushless outrunner motors, installed at the chassis center line. To fit everything together, he had to 3D print new drive cups from stainless steel. The Mi5’s CVD drive shafts had to be cut down, and new carbon fiber suspension towers had to be designed and cut.

The real magic lies in [HammerFET’s] custom control board. He’s using an STM32F4 ARM processor and an InvenSense MPU-6050 IMU which drone pilots have come to know and love. Hall effect sensors mounted above each motor keep track of the wheel speed, much like an ABS ring on a full-scale car.

[HammerFET’s] software is created with MATLAB and SimuLink. He uses SimuLink’s embedded coder plugin to export his model to C, which runs directly on his board. Expensive software packages for sure, but they do make testing control algorithms much simpler. [HammerFET’s] code is available on Github.

Since everything is controlled by software, changing the car’s drive system is as simple as tweaking a few values in the code. Front and rear power offset is easily changed. Going from a locked spool to an open differential is as simple as changing a value from 0 to 1. Pushing the differential value past 1 literally overdrives the differential. In a turn, the outer wheel will be driven faster than it would be on a mechanical differential, while the inner wheel is slowed down. Fans of drifting will love this setting!

[HammerFET] is still working on his software, he hopes to implement electronic torque vectoring. Interested? Check out the conversation over on his Reddit thread.

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Google Cardboard VR Kit For Under $15

July 12, 2014 by James Hobson 15 Comments

Craving some virtual reality goodness? Unsure of Oculus after Facebook purchased them? Well — why not make your own then!

At last weeks Google I/O conference, those lucky enough to attend received the Google Cardboard VR kit. It’s basically just a piece of cardboard, two lenses, a few magnets, an NFC tag and some velcro — but when you slide your phone into it and download the Cardboard app — you have virtual reality, on your phone.

This inspired [Wolfgang] to make his own variation of this, except instead of a phone, it fits a tablet much nicer. It really is just a cardboard box with the lenses glued in place — but it works! Of course you could 3D print a nice housing — but if you’re super excited to try out some VR apps — cardboard will do the trick as well!

Besides the Cardboard app there’s a few more Android VR applications worth a look — Tuscany Dive (explore Tuscany from the comfort of your chair), ViewR (a voice controlled experience), and Dive Volcano VR Demo (explore a volcano!).

Only trick is finding those pesky lenses…