How does one go about measuring the amount of light in a given area? With a Light Meter of course! Maintaining proper lighting levels can be very important in places like schools, hospitals and even your own workbench.
[Raj] over at Embedded Labs has put together an excellent tutorial on how to construct your very own light meter based upon the chipKIT platform. The chipKIT Uno32 is similar to Arduino, but boasts a much more powerful PIC32MX320F128 microcontroller. We’ve seen projects that feature the chipKIT Uno (pdf warning) here before. From playing pong to hosting several temperature sensors, it’s certainly a versatile platform.
The light meter uses an I/O shield and communicates to a BH1750FVI digital light sensor via I2C. The firmware divides the raw data coming off the sensor by a constant, and displays the light intensity data on an OLED display in Lux, foot-candles, and Watts/m^2 units. Be sure to check out the tutorial for full schematics and source.
We’re really starting to enjoy the home entertainment control hacks which use a universal receiver to act on commands from any remote. This one is especially interesting as it uses a single remote to control the system but rolls in lots of extras.
Looking at the receiver itself the white plastic dome of the PIR sensor should raise an eyebrow. Since the cable box takes a while to turn on [Ivan] included the motion sensor to switch that component on when you walk into the room. This way it’ll be ready to go by the time you sit down. It does this by sending IR signals from the PIC32 dev board. Of course the board has its own receiver to listen for the remote control commands. The remote buttons have been mapped a bit differently than originally intended. You can see in the diagram above that the normal VCR/DVD/DVR buttons have been set to control the room’s LED strips. There’s even a power consumption monitor rolled into the project. All of these features are demonstrated in the clip after the break.
This is a nearly perfect base setup. But we’d love to see it with a web interface at some point in the future.
Continue reading “Eloquent universal receiver for your home entertainment equipment”
Here’s a new take on the QR clock concept that uses an LCD display. The concept comes from the work [ch00f] put into his two versions of a QR clock (both of which used LED arrays). The time of day is encoded using the Quick Response Code standard. This version generates a new code each second which encapsulates date, hour, minute, and second information. If you look at the image on the left you’ll notice the code is not centered. Take a look at the video after the break and you’ll see that’s because it’s bouncing around the LCD like a screensaver. Watch a little longer and you’ll see the psychedelic effects shown in the image on the right.
A PIC32 is driving the display. It’s connected to a DCF77 radio module which feeds the system atomic clock data. The color plasma effects are used to show when the device has locked onto the radio signal.
Continue reading “LCD-based QR clock”
Building guitar pedals has come a long way from hooking up a few transistors and building a simple boost circuit. [Cloudscapes] has been working on a Anti-nautilus auto glitch, auto repeat pedal, and if you’re looking for something that sounds like a spaghetti western soundtrack skipping on a record player, we couldn’t think of anything better.
[Cloudscapes] was already familiar with 8-bit AVRs, but when doing real-time audio sampling, a more powerful microcontroller was in order. He turned to the MikroElektronika MINI-32 board for development purposes. This small board fits a PIC32 microcontroller into an easily breadboardable DIP-40 form factor, perfect for playing around with some very capable hardware.
For the DAC, [Cloudscapes] had some experience with the 16-bit PT8211, but finding a good 16-bit ADC in a convenient package was a bit of a challenge. He eventually settled on the 12-bit MCP3201 ADC, more than enough for a pedal that is supposed to sound lo-fi.
After [Cloudscapes] got a few boards made, he started on his DSP adventure. Unfortunately, the initial code used unsigned 16-bit words to represent each sample, meaning every time the loop repeated it would start at 0 and produce a short pop in the speaker. After a week of debugging, [Cloudscapes] realized signed integers are a much better data format for storing audio data and got rid of the problems plaguing his project.
Now [Cloudscapes] has a wonderful DSP dev board, perfect for making new and strange guitar effects. After the break you can listen to a demo of what the Anti-nautilus pedal actually does, and we’ve got to say it sounds great.
Thanks [Chris] for sending this one in.
Continue reading “Playing with DSP and building a guitar pedal”
The Atari POKEY served as the main I/O chip on the venerable Atari 400/800 and XL/XE 8-bit computers. While a chip designed to get voltages from game paddles and scanning a matrix of keyboard switches wouldn’t normally be remembered 30 years later, the POKEY had another function: generating very, very distinctive music and sound effects for those old Atari games. [Markus Gritsch] wanted a portable version of the POKEY, so he emulated one on a modern microcontroller. Now he’s able to take those old Atari chiptunes where ever he goes.
The build uses the Another Slight Atari Player by emulating a 6502 and POKEY chip inside [Markus]’ PIC32MX-based microcontroller. There’s not much physical hardware [Markus] had to deal with – the board is built on a QFP proto board [Markus] picked up with a few buttons and a jack added for some simple I/O.
This isn’t [Markus]’s first attempt at portabalizing chiptunes – last year, we saw a truly awesome portable SID player that used the same PIC32 microcontroller and an emulated 6502. Between the Atari SAP Music Archive and the High Voltage SID Collection, [Markus] has more than enough chiptunes for days of listening pleasure.
Any self-identified geek that spent some time in the 80s will tell you how they used to type out programs into their ‘microcomputer’ with BASIC. It was a simpler time when a computer’s raison d’etre was simply being a BASIC interpreter. These days are long past us now; you can’t simply turn on a computer and have it load a BASIC prompt anymore. This is where [Geoff]’s Maximite single board computer comes in. It’s a tiny little box that whose only purpose is to play around with BASIC.
[Geoff]’s used a PIC32MX microcontroller with 128k of RAM for the CPU of his Maximite. Unlike an Apple ][ or TRS-80, the Maximite version of BASIC can do floating point arithmetic out of the box. To connect to the outside world, the Maximite has VGA or composite out to display the BASIC interepreter. A PS/2 keyboard port provides the input, and a USB port and SD card can be used to load and save programs from a PC.
The Maximite includes a 20-pin breakout for whatever IO you can imagine. This is duplicated on [Geoff]’s mini Maximite that is designed to be the retro throwback of an Arduino. We though those were called BASIC stamps, but if it gets kids programming, we’ll let it slide.
Here’s a photo of the circuit board for the Maximite, a BASIC interpreter that [Geoff] built. The design idea was sparked when he was exploring the possibilities of the PIC32 family of chips. [Geoff] wanted to write about the hardware for a magazine article but needed an actual product to really show it off.
The design can utilize one of two microprocessors, a PIC 32MX795F512H or 32MX695F512H. The 32-bit chip has more than enough power to emulate BASIC, and even allows for floating point calculations. It’s VGA compatible and has a jack for a standard PS/2 keyboard, which makes it a standalone device. You can store programs on an SD card, or it can be interfaced with a computer via the USB-B port that you see next to the power jack. The microprocessor is a surface mount chip, but the rest of the components are through-hole, making this an easy kit to assemble. But if you’re not afraid to etch your own 2-layered PCBs there is board artwork available in [Geoff’s] download package.