Microchip’s PIC32MZ DA — The Microcontroller With A GPU

When it comes to displays, there is a gap between a traditional microcontroller and a Linux system-on-a-chip (SoC). The SoC that lives in a smartphone will always have enough RAM for a framebuffer and usually has a few pins dedicated to an LCD interface. Today, Microchip has announced a microcontroller that blurs the lines between what can be done with an SoC and what can be done with a microcontroller. The PIC32MZ ‘DA’ family of microcontrollers is designed for graphics applications and comes with a boatload of RAM and a dedicated GPU.

The key feature for this chip is a boatload of RAM for a framebuffer and a 2D GPU. The PIC32MZ DA family includes packages with 32 MB of integrated DRAM designed to be used as framebuffers. Support for 24-bit color on SXGA (1280 x 1024) panels is included. There’s also a 2D GPU in there with support for sprites, blitting, alpha blending, line drawing, and filling rectangles. No, it can’t play Crysis — just to get that meme out of the way — but it is an excellent platform for GUIs.

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32-Bit Processing For The Vectrex Arcade System

Alongside the Commodores, Ataris, Nintendos, and all the other game systems of the 80s, there was a single unique video game system that stood out from the pack. This was the Vectrex, a console with a built-in CRT meant to display vector graphics and only vector graphics. The video game crash of 1983 wasn’t kind to the Vectrex, but it still lives on with a reasonably popular homebrew scene. Still, these homebrew games are limited by the hardware itself. After thirty years, the Vectrex has an upgrade. The Vectrex32 is a coprocessor, designed for the Vectrex cartridge slot, that gives this ancient console better graphics and 32-bit capabilities.

There’s a whole site dedicated to this Vectrex add-on, and the hardware is pretty much what you would expect. There’s a fast PIC32 microcontroller on this cartridge, a USB port, and a dual-port memory chip that’s connected to the Vectrix’s native processor.

Since this add-on cartridge is effectively a computer itself,  the Vectrex32 can operate as a BASIC interpreter for the Vectrex. That’s something the original hardware couldn’t have done, and makes homebrew development much easier.

You can check out a few videos describing the functionality of the Vectrex32 below, along with a few gameplay videos of new homebrew games written specifically for the Vectrex.

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Building A Wavetable Synth

Every semester at one of [Bruce Land]’s electronics labs at Cornell, students team up, and pitch a few ideas on what they’d like to build for the final project. Invariably, the students will pick what they think is cool. The only thing we know about [Ian], [Joval] and [Balazs] is that one of them is a synth head. How do we know this? They built a programmable, sequenced, wavetable synthesizer for their final project in ECE4760.

First things first — what’s a wavetable synthesizer? It’s not adding, subtracting, and modulating sine, triangle, and square waves. That, we assume, is the domain of the analog senior lab. A wavetable synth isn’t a deep application of a weird reverse FFT — that’s FM synthesis. Wavetable synthesis is simply playing a single waveform — one arbitrary wave — at different speeds. It was popular in the 80s and 90s, so it makes for a great application of modern microcontrollers.

The difficult part of the build was, of course, getting waveforms out of a microcontroller, mixing them, and modulating them. This is a lab course, so a few of the techniques learned earlier in the semester when playing with DTMF tones came in very useful. The microcontroller used in the project is a PIC32, and does all the arithmetic in 32-bit fixed point. Even though the final audio output is at 12-bit resolution, the difference between doing the math at 16-bit and 32-bit was obvious.

A synthesizer isn’t useful unless it has a user interface of some kind, and for this the guys turned to a small TFT display, a few pots, and a couple of buttons. This is a complete GUI to set all the parameters, waveforms, tempo, and notes played by the sequencer. From the video of the project (below), this thing sounds pretty good for a machine that generates bleeps and bloops.

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Your Arm Is The Ideal Controller

With interest and accessibility to both wearable tech and virtual reality approaching an all-time high, three students from Cornell University — [Daryl Sew, Emma Wang, and Zachary Zimmerman] — seek to turn your body into the perfect controller.

That is the end goal, at least. Their prototype consists of three Kionix tri-axis accelerometer, gyroscope and magnetometer sensors (at the hand, elbow, and shoulder) to trace the arm’s movement. Relying on a PC to do most of the computational heavy lifting, a PIC32 in a t-shirt canister — hey, it’s a prototype! — receives data from the three joint positions, transmitting them to said PC via serial, which renders a useable 3D model in a virtual environment. After a brief calibration, the setup tracks the arm movement with only a little drift in readings over a few minutes.

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Motorized Camera Dolly Rolls With the Changes

Over the last semester, Cornell student [Ope Oladipo] had the chance to combine two of his passions: engineering and photography. He and teammates [Sacheth Hegde] and [Jason Zhang] used their time in [Bruce Land]’s class to build a motorized camera dolly for shooting time-lapse sequences.

The camera, in this case the one from an iPhone 6, is mounted to an off-the-shelf robot chassis that tools around on a pair of DC motors. The camera mount uses a stepper motor to get just the right shot. A PIC32 on board the ‘bot takes Bluetooth commands from an iOS app that the team built. The dolly works two ways: it can be controlled manually in free mode, or it can follow a predetermined path at a set speed for a specified time in programmed mode.

Our favorite part of the build? The camera’s view is fed to a smart watch where [Ope] and his team can take still pictures using the watch-side interface. Check it out after the break, and stick around for a short time-lapse demo. We’ve featured a couple of dolly builds over the years. Here’s a more traditional dolly that rides a pair of malleable tubes.

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This Bike Sonar is Off the Chain

On paper, bicycling is an excellent form of transportation. Not only are there some obvious health benefits, the impact on the environment is much less than anything not directly powered by a human. But let’s face it: riding a bike can be quite scary in practice, especially along the same roads as cars and trucks. It’s hard to analyze the possible threats looming behind you without a pair of eyes in the back of your head.

radar-sweep-display[Claire Chen] and [Mark Zhao] have come up with the next best thing—bike sonar. It’s a two-part system that takes information from an ultrasonic rangefinder and uses it to create sound-localized pings in a rider’s ears. The rangefinder is attached to a servo mounted on the seat post. It sweeps back and forth to detect objects within 4 meters, and this information is displayed radar-sweep-style graphic on a TFT screen via a PIC32.

Though the graphic display looks awesome, it’s slow feedback and a bit dangerous to have to look down all the time — the audio feedback is by far the most useful. The bike-side circuits sends angle and distance data over 2.4GHz to another PIC mounted on a helmet. This PIC uses sound localization to create a ping noise that matches the distance and location of whatever is on your tail. The ping volume is relative to the distance of the object, and you just plug headphones into the audio jack to hear them. Bunny-hop your way past the break to check it out.

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Cornell Students Have Your Back

Back problems are some of the most common injuries among office workers and other jobs of a white-collar nature. These are injuries that develop over a long period of time and are often caused by poor posture or bad ergonomics. Some of the electrical engineering students at Cornell recognized this problem and used their senior design project to address this issue. [Rohit Jha], [Amanda Pustis], and [Erissa Irani] designed and built a posture correcting device that alerts the wearer whenever their spine isn’t in the ideal position.

The device fits into a tight-fitting shirt. The sensor itself is a flex sensor from Sparkfun which can detect deflections. This data is then read by a PIC32 microcontroller. Feedback for the wearer is done by a vibration motor and a TFT display with a push button. Of course, they didn’t just wire everything up and call it a day; there was a lot of biology research that went into this. The students worked to determine the most ideal posture for a typical person, the best place to put the sensor, and the best type of feedback to send out for a comfortable user experience.

We’re always excited to see the senior design projects from university students. They often push the boundaries of conventional thinking, and that’s exactly the skill that next generation of engineers will need. Be sure to check out the video of the project below, and if you want to see more of this semester’s other projects, we have you covered there tooContinue reading “Cornell Students Have Your Back”