How do you get 16-bit audio out of an 8-bit microcontroller. We’ll give you a hint: two pins are used. Not helping? Here it comes: two 8-bit DACs PWM outputs are used on this chip, the ATmega1284. One is used for the lower eight bits, the other handles the upper. The two are combined using carefully calculated precision resistor values and the results are beyond what you imagine. This is produced at a bitrate of 44077.135, slightly off from the 44100Hz standard but we challenge you audiophiles to tell the difference. The wave files are served from an SD card read by the chip using the Petit-FatFs library.
There are so many great things about this project. First off, following [Wancheng Zhou’s] example will let anyone with even basic microcontroller skills build a digital audio player for an [Andrew Jackson] and a couple of [Washingtons]. Secondly, those with a medium uC skill level will want to take the idea and implement/debug it for themselves. Bringing it home, [Wancheng] shows how to gauge the quality of the audio output using FFT.
If you didn’t figure it out by the time of year, this is yet another example of a Cornell ECE 4760 final project. Shout out to [Bruce Land] for inspiring awesome projects and requiring extensive documentation of the projects which itself promotes deeper understand all around.
So you got CHDK working on your camera, and the histograms, raw image files, variable shutter speeds and other added functions are amazing, but stereo imaging is what you really want. If you have two or more CHDK-ready cameras, it’s cheap and easy to run StereoData Maker, a system that synchronizes the shutter and flash of multiple cameras.
The first step in getting SDM to work is installing the software on your SD card. You’ll need to find the correct version for you camera; a list is available on the main SDM page. If you are running Windows XP or Vista, run the installer in the zip file. Otherwise, load the files on the SD card and run the installer directly from the camera. Then decide whether this will be the right or left camera and repeat the steps for your second camera.
Next, you’ll need to prepare a switch unit, essentially a set of synchronized USB remotes. There are many ready made commercial units available, but building one on your own shouldn’t be much trouble, and a few ideas are provided on the SDM instruction page.
You’re basically ready to start shooting stereo images, just take a few test shots to get used to it and to customize the configuration on the cameras.
The WiFi uploading Eye-Fi SD card made a big splash when it was first introduced, but now Eye-Fi has a whole line of different products. The top of the line is the Eye-Fi Explore, which supports geotagging without using a GPS. Instead of GPS hardware, it uses the Skyhook Wireless Wi-Fi Postitioning System, which correlates the position of the Eye-Fi’s access point to GPS locations, creating virtual GPS functionality. This allows photos taken with the Eye-Fi to be be geotagged. Of course, the accuracy of the system is noticeably lower than true GPS and seems to be affected by a number of external factors, but it is still accurate enough to tag the photo within the immediate vicinity of where it was taken.
WiFi positioning is great feature, but certainly not limited to photography. Since the Eye-Fi is at its core SD storage media, you could probably have it geotag data saved to the card, even if it wasn’t created by a digital camera..