JPEG

10 Articles

A Year Long Time Lapse Camera

December 22, 2014 by 19 Comments

All [val3tra] wanted was an RF-accessible camera. A camera that would take pictures, save them to an SD card, and occasionally send them over an RF link to a computer. This project has grown out of control, and now it has become an open-source camera that’s able to take year-long time-lapse movies.

The build started as a low power camera using an eBay JPEG camera modified for 3.3V. That’s only 640×480, but each frame averages only 48kb – small enough to store a few thousand pictures on a FAT16 formatted SD card. A $4 RF module, an ATMega, and an RTC make up the rest of the build that has a power draw of about 100 Joules per hour. A D-cell has about 60,000 Joules, and a pessimistic estimate of a battery of four in series, two in parallel gives a run time of 200 days.

This build was then improved, bringing the total battery consumption down to about 3.5-4 Joules per frame, or at one frame every 10 minutes, about 24 Joules an hour. That’s impressive, and getting this camera to run longer than a dozen or so months raises some interesting challenges. The self-discharge of the battery must be taken into account, and environmental concerns – especially when leaving this camera to run in a Moscow winter, seen in the video below – are significant.

If you don’t want to go equipment-lite you could seal your DSLR, Pi, and some serious batteries in a weatherproof enclosure.

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Towards More Interesting Instant Cameras

December 18, 2014 by 22 Comments

When [Ch00f] was getting jeans rung up at Nordstroms, he noticed how fast thermal receipt printers can put an image on a piece of paper. This observation isn’t unique to the circles [Ch00f] frequents – there are a few small receipt paper printers out there that connect to the Internet, iPhones, and a whole bunch of other Kickstarter-friendly keyword devices.

Nevertheless, a device that can make a hard copy of an image quickly and cheaply isn’t something you just stop thinking about. After rolling the concept around in his head for a few years, [Ch00f] finally came up with the perfect build – a camera.

The hardware for the build is based around an STM32F4 Discovery board. It’s a bit overpowered for this sort of application, and this is one of [Ch00f]’s first adventures in ARM-land. The rest of the hardware consists of a thermal receipt printer and a JPEG camera, the latter of which replaced a cellphone CMOS camera module that was lost in a move.

A custom camera requires a custom enclosure, and for this [Ch00f] made something remarkable. The entire enclosure is CNC milled out of a beautiful piece of figured walnut. The end result looks far too good for a prototype, but it does polish up nicely with a bit of linseed oil.

Now [Ch00f] has an instant camera that takes the idea of a Polaroid and turns it into something that produces a print for tenths of a cent. There’s a time-lapse function – just a zip tie on the shutter button – filters with the help of highlighters, and the ability to record movies in flipbook format.

It’s a great project, and also something that will make for a great crowdfunding campaign. [Ch00f] has already started work on this. He already has a sleek, modern-looking website that requires far too much scrolling than should be necessary – the first step to a winning Kickstarter. [Ch00f] also learned a lot about ARMs, DMA, dithering, gamma correction, and the JPEG format, but that’s not going to get anyone to open up their wallet. You know what will? A slick video. You’ll find that below.

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Serial Camera, Courtesy Of The STM32F4

December 4, 2014 by 47 Comments

Look around for a small, embedded camera module, and you’ll find your options are rather limited. You have the serial JPEG cameras, but they’re rather expensive and only have VGA resolution. A Raspi, webcam, and power supply is a false economy. GoPros are great, but you’re still looking at some Benjamins used.

The guys at GHI Electronics are taking a different tack. They’re using image sensors you would normally find in cellphones and webcams, adding a powerful ARM processor, and are still able to sell it for about $50. It’s called the ALCAM, and they’ve stumbled upon a need that hasn’t been met by any manufacturer until now.

On board the ALCAM is an OV3640 3-Megapixel image sensor. On the back of the board is a STM32F4 and a microSD card slot. The board can be set up for time-lapse videos, stop motion animation, or all the usual serial board camera functions, including getting images over a serial connection.

The ALCAM operates either connected to a PC though a 3.3V serial adapter cable, through a standalone mode with pins connected to a button or sensor, to the SPI bus on a microcontroller, or a serial to Bluetooth or WiFi bridge. Images can be saved to the uSD card, or sent down the serial stream.

It’s a pretty cool board, and if you’re thinking it looks familiar, you’re right: there’s a similar DSI camera/STM32F4 board that was an entry to The Hackaday Prize. Either way, just what we need to get better cameras cheaper into projects.