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.

Astrophotography and Data-Analysis Sense Exoplanets

[David Schneider] was reading about recent discoveries of exoplanets. Simply put these are planets orbiting stars other than the sun. The rigs used by the research scientists include massive telescopes, but the fact that they’re using CCD sensors led [David] to wonder if a version of this could be done on the cheap in the backyard. The answer is yes. By capturing and processing data from a barn door tracker he was able to verify a known exoplanet.

Barn Door trackers are devices used to move a camera to compensate for the turning of the earth. This is necessary when taking images throughout the night, as the stars will not remain “stationary” to the camera’s frame without it. The good news is that they’re simple to build, we’ve seen a few over the years.

Other than having to wait until his part of the earth was pointed in the correct direction (on a clear night) at the same time as an exoplanet transit, [David] was ready to harvest all the data he needed. This part gets interesting really quickly. The camera needed to catch the planet passing in between the earth and the star it revolves around (called a transit). The data to prove this happened is really subtle. To uncover it [David] needed to control the data set for atmospheric changes by referencing several other stars. From there he focused on the data for the transit target and compared points across the entire set of captured images. The result is a dip in brightness that matches the specifications of the original discovery.

[David] explains the entire process in the clip after the break.

Continue reading “Astrophotography and Data-Analysis Sense Exoplanets”

Analog Instagram

Several decades ago, the all the punks and artsy types had terrible lenses with terrible camera that leaked light everywhere. Film was crap, and thus was born the fascinating world of Lomography, with effects and light leaks unique to individual cameras. Now, everyone has a smartphone with high-resolution sensors, great lenses, and Instagram to replicate the warm look of filters, light leaks, and other ‘artististic’ photographic techniques. The new version of this photography is purely in the digital domain, and wouldn’t it be great if there was a way to make your digital selfies analog once again? The SnapJet team has your back.

Instead of adding filters and other digital modifications to smartphone snaps, the SnapJet prints pictures onto Polaroid film. Yes, you can still buy this film, and yes, it’s exactly how you remember it. By putting a smartphone down on the SnapJet, you’ll only need to press a button, wait for the film to be exposed, dispensed, and developed. What comes out of the SnapJet is an analog reproduction of whatever is displayed on your phone’s screen, with all the digital filters you can imagine and the option to modify the photos in the analog domain; eac Polaroid can be turned into a transparency, with backlit LEDs being an obvious application:

gif

Continue reading “Analog Instagram”

Simple Thermal Imager with a Lepton Module

[Andrew] designed a simple thermal imager using the FLIR Lepton module, an STM32F4 Nucleo development board, and a Gameduino 2 LCD. The whole design is connected using jumper wires, making it easy to duplicate if you happen to have all the parts lying around (who doesn’t have a bunch of thermal imaging modules lying around!?).

The STM32F4 communicates with the Lepton module using a driver that [Andrew] wrote over a 21MHz SPI bus. The driver parses SPI packets and assembles frames as they are received. Images can be mapped to pseudocolor using a couple different color maps that [Andrew] created. His code also supports min/max scaling to map the pseudocolor over the dynamic range present in the image.

Unfortunately the Lepton module that [Andrew]’s design is based is only sold in large quantities. [Andrew] suggests ripping one out of a FLIR ONE iPhone case which are more readily available. We look forward to seeing what others do with these modules once they are a bit easier to buy.

An External Autofocus for DSLRs

Most modern DSLR cameras support shooting full HD video, which makes them a great cheap option for video production. However, if you’ve ever used a DSLR for video, you’ve probably ran into some limitations, including sluggish autofocus.

Sensopoda tackles this issue by adding an external autofocus to your DSLR. With the camera in manual focus mode, the device drives the focus ring on the lens. This allows for custom focus control code to be implemented on an external controller.

To focus on an object, the distance needs to be known. Sensopoda uses the HRLV-MaxSonar-EZ ultrasonic sensor for this task. An Arduino runs a control loop that implements a Kalman filter to smooth out the input. This is then used to control a stepper motor which is attached to the focus ring.

The design is interesting because it is rather universal; it can be adapted to run on pretty much any DSLR. The full writeup (PDF) gives all the details on the build.

How to Backup and Restore Your IP Camera Firmware

[Filipe] has been playing around with custom firmware for inexpensive IP cameras. Specifically, he has been using cameras based on a common HI3815 chip. When you are playing around with firmware like this, a major concern is that you may end up bricking the device and rendering it useless. [Filipe] has documented a relatively simple way to backup and restore the firmware on these cameras so you can hack to your heart’s content.

The first part of this hack is hardware oriented. [Filipe] cracked open the camera to reveal the PCB. The board has labeled serial TX and RX pads. After soldering a couple of wires to these pads, [Filipe] used a USB to serial dongle to hook his computer up to the camera’s serial port.

Any terminal program should now be able to connect to the camera at 115200 baud while the camera is booting up. The trick is to press “enter” during the boot phase. This allows you to log in as root with no password. Next you can reset the root password and reboot the camera. From now on you can simply connect to the phone via telnet and log in as root.

From here, [Filipe] copies all of the camera’s partitions over to an NFS share using the dd command. He mentions that you can also use FTP for this if you prefer. At this point, the firmware backup is completed.

Knowing how to restore the backup is just as important as knowing how to create it. [Filipe] built a simple TFTP server and copied the firmware image to it in two chunks, each less than 5MB. The final step is to tell the camera how to find the image. First you need to use the serial port to get the camera back to the U-Boot prompt. Then you configure the camera’s IP address and the TFTP server’s IP address. Finally, you copy each partition into RAM via TFTP and then copy that into flash memory. Once all five partitions are copied, your backup is safely restored and your camera can live to be hacked another day.

An MSP430 Clone of the Canon RC-1 Remote

For reasons we both agree with and can’t comprehend, most ‘prosumer’ SLR cameras don’t have mechanical shutter releases. Instead, IR LEDs are brought into the mix, the Canon RC-1 remote trigger being the shutter release of choice for people who didn’t choose Nikon. [Vicente] cloned the Canon RC-1, but he didn’t do it to save money; there’s a lot to learn with this project, and making his own allows him to expand it with more features in the future.

Studying the function of the Canon RC-1, [Vicente] found that some compromises needed to be made. The total power emitted by an IR LED is usually a function of its beamwidth; a smaller beamwidth means more photons reaching the IR receiver in the camera. This also means the remote must be aimed at the camera more accurately. In the end, [Vicente] decided on a higher power LED with a tighter beamwidth that’s just slightly below the optimum wavelength for the receiver. It’s all an exercise in compromise, but other components could see similar performance.

With the LED selected, [Vicente] moved on to building the actual controller. He chose an MSP430 microcontroller for its low power consumption, driving the LED with a watch battery and a transistor. Put together on a piece of protoboard, it’s actually pretty close to a TV-B-Gone. With everything soldered up, it’s good enough to trigger his camera’s shutter from about 5 meters away. Future improvements include cleaning up the code, making the timing more accurate with a crystal, and implementing low power mode on the MSP430.