Multiplexing Pi Cameras

The Raspberry Pi and its cool camera add-on is a great way to send images and video up to the Intertubes, but what if you want to monitor more than one scene? The IVPort can multiplex up to sixteen of these Raspi camera modules, giving the Pi sixteen different views on the world and a ridiculously high stack of boards connected to the GPIO header.

The Raspberry Pi’s CSI interface uses high-speed data lines from the camera to the CPU to get a lot of image data quickly. Controlling the camera, on the other hand, uses regular old GPIOs, the same kind that are broken out on the header. We’ve seen builds that reuse these GPIOs to blink a LED, but with a breakout board with additional camera connectors, it’s possible to use normal GPIO lines in place of the camera port GPIOs.

The result is a stackable extension board that splits the camera port in twain, allowing four Raspi cameras to be connected. Stack another board on top and you can add four more cameras. A total of four of these boards can be stacked together, multiplexing sixteen Raspberry Pi cameras.

As far as the obvious, ‘why’ question goes, there are a few interesting things you can do with a dozen or so computer controlled cameras. The obvious choice would be a bullet time camera rig, something this board should be capable of, given its time to switch between channels is only 50ns. Videos below.

Continue reading “Multiplexing Pi Cameras”

Towards More Interesting Instant Cameras

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.

Continue reading “Towards More Interesting Instant Cameras”

Improving A Modern Instant Camera

Instant film never went away – Fujifilm has been producing instant film for decades before Polaroid ceased production. Yes, cries of a lost photographic heritage were all for naught, and you can still buy an instant camera. [Dan] picked up a Fujifilm Instax Wide camera – an instant camera that produces not-square images – and figured some electronic tinkering could vastly expand the capabilities of this camera. He took it apart and made some modifications, giving it a bulb mode for long exposures and multi-exposure capability.

[Dan] began his tinkering by figuring out how to put multiple exposures on one frame of film. The Instax Wide camera has an eject sensor, a wire for the shutter button, and a few wires leading to the motor. By adding a switch to turn off the motor and a pushbutton to bypass the ejection sensor, [Dan] can stack multiple exposures on a single frame of film.

Multiple exposures are one thing, but how about longer exposures for light painting and all those other cool things you can do with microcontrolled LEDs? Modding the camera for that is pretty easy. All you need are a few mini toggle switches. It’s just a simple matter of opening the shutter for as long as you need, painting a scene with light, and flipping a few more switches to eject the film. [Dan] is getting some pretty respectable exposures with this – somewhat impressive considering the camera’s fixed aperture.

Serial Camera, Courtesy of the STM32F4

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.

ArTICam Interfaces Game Boy Camera with TI Calculators

[Christopher Mitchell] has given Texas Instruments calculators the ability to capture images through a Game Boy Camera with ArTICam. First introduced in 1998, The Game Boy Camera was one of the first low-cost digital cameras available to consumers. Since then it has found its way into quite a few projects, including this early Atmel AT90 based hack, and this Morse code transceiver.

TI calculators don’t include a Game Boy cartridge slot, so [Christopher] used an Arduino Uno to interface the two. He built upon the Arduino-TI Calculator Linking (ArTICL) Library  to create ArTICam. Getting the Arduino to talk with the Game Boy Camera’s M64282FP image sensor turned out to be easy, as there already are code examples available. The interface between the camera sensor and the Arduino is simple enough. 6 digital lines for an oddball serial interface, one analog sense line, power and ground. [Christopher] used a shield to solder everything up, but says you can easily get away with wiring directly the Arduino Uno’s I/O pins. The system is compatible with the TI-83 Plus and TI-84 Plus family of calculators. Grabbing an image is as simple as calling  GetCalc(Pic1) from your calculator program.

So, If you have an old calculator lying around, give it a try to enjoy some 128×123-pixel grayscale goodness!

Keep Tabs on Passing Jets with Pi and SDR

Obviously Software Defined Radio is pretty cool. For a lot of hackers you just need the right project to get you into it. Submitted for your approval is just that project. [Simon Aubury] has been using a Raspberry Pi and SDR to record video of planes passing overhead. The components are cheap and most places have planes passing by; this just might be the perfect project.

We’re not just talking static frames with planes passing through them, oh no. Simon used two hobby servos and some brackets to gimbal his Pi camera board. A DVB dongle allows the rig to listen in on the Automatic Dependent Surveillance Broadcast (ADS-B) coming from the planes. This system is mandated for most commercial aircraft (deadlines for implementation vary). ADS-B consists of positioning data being broadcast from planes using known frequencies and protocols. Once [Simon] locks onto this data he can accomplish a lot, like keeping the plane in the center of the video, establishing which flight is being recorded, and automatically uploading the footage. With such a marvelously executed build we’re certain we will see more people giving it a try.

[Simon] did a great job with the writeup too. Not only did he include a tl;dr, but drilled down through a project summary and right to the gritty details. Well done documentation is itself worth celebrating!

Continue reading “Keep Tabs on Passing Jets with Pi and SDR”

An Extremely Tiny 5.8GHz FPV Transmitter

Flying RC aircraft with a first person view is the latest and greatest thing in the hobby. In a fact that I’m sure will be shocking to 90% of people, you don’t need to buy a Phantom quad fly FPV. The guys at Flite Test show how you can build a tiny 5.8GHz FPV transmitter for under $100.

The parts used for this build are pretty much jelly bean parts at this point, but [Peter] at Flite Test is going for extremely lightweight parts for this build. He found an NTSC board camera that only weighs 1g and added a wide-angle lens. The transmitter is a tiny 200mW module that only weighs about 2g.

Why are the Flite Test crew going for small and light FPV setups? They just launched a new line of planes that can be built from a single piece of foam board. If you have a small micro quad, you can easily add FPV to it with this rig.