Whether you’re selling a product or just showing off your latest project, a photo turntable makes video shots a lot easier. 360° turntables allow the viewer to see every side of the object being photographed, while the camera stays locked down. Motorized turntables are available as commercial products costing anywhere from $30 to $150 or so. Rather than shell out cash, [NotionSunday] decided to create his own turntable using a few parts he had on hand and 3D printing everything else.
The motor for the turntable came from the eject mechanism of an old DVD-ROM drive. An Arduino Pro Mini controls the motor’s speed using an MX1508 H-bridge chip. Power comes from an 18650 Li-Ion battery. The whole assembly spins on the head assembly from a VCR.
Before you jump in on the comments, yes, VCR heads have motors. However, they’re typically brushless motors rated for 1,800 RPM. Running a motor like that at low-speed would mean rewinding the coils. In this case, using a DC motor and gear drive was the easier option.
[NotionSunday] 3D printed the turntable base and mount. The mount uses a magnet arrangement that makes it easy to switch between freewheeling or belt driven operation. The turntable itself is posterboard, with 3D printed edges.
What makes [mwagner1]’s Raspberry Pi Zero-based WiFi camera project noteworthy isn’t so much the fact that he’s used the hardware to make a streaming camera, but that he’s taken care to document every step in the process from soldering to software installation. Having everything in one place makes it easier for curious hobbyists to get those Pi units out of a drawer and into a project. In fact, with the release of the Pi Zero W, [mwagner1]’s guide has become even simpler since the Pi Zero W now includes WiFi.
Using a Raspberry Pi as the basis for a WiFi camera isn’t new, but it is a project that combines many different areas of knowledge that can be easy for more experienced people to take for granted. That’s what makes it a good candidate for a step-by-step guide; a hobbyist looking to use their Pi Zero in a project may have incomplete knowledge of any number of the different elements involved in embedding a Pi such as basic soldering, how to provide appropriate battery power, or how to install and configure the required software. [mwagner1] plans to use the camera as part of a home security system, so stay tuned.
If Pi Zero camera projects catch your interest but you want something more involved, be sure to check out the PolaPi project for a fun, well-designed take on a Pi Zero based Polaroid-inspired camera.
Who doesn’t love a good robot? If you don’t — how dare you! — then this charming little scamp might just bring the hint of a smile to your face.
SDDSbot — built out of an old Sony Dynamic Digital Sound system’s reel cover — can’t do much other than turn left, right, or walk forwards on four D/C motor-controlled legs, but it does so using the power of a Pixy camera and an Arduino. The Pixy reads colour combinations that denote stop and go commands from sheets of paper, attempting to keep it in the center of its field of view as it toddles along. Once the robot gets close enough to the ‘go’ colour code, the paper’s orientation directs the robot to steer itself left or right — the goal being the capacity to navigate a maze. While not quite there yet, it’s certainly a handful as it is.
As much as we’d like to have the right tools for the right job all of the time, sometimes our parts drawers have other things in mind. After all, what’s better than buying a new tool than building one yourself from things you had lying around? That’s at least what [Saulius] must have been thinking when he needed a thermometer with a digital output, but only had a dumb, but feature-rich, thermometer on hand.
Luckily, [Saulius] had a webcam lying around as well as an old thermometer, and since the thermometer had a LCD display it was relatively straightforward to get the camera to recognize the digits in the thermometer’s display. This isn’t any old thermometer, either. It’s a four-channel thermometer with good resolution and a number of other useful features (with an obvious lack of communications abilities), so it’s not something that he could just overlook.
Once the camera was mounted to an arm and pointed at the thermometer’s screen, an algorithm running on a computer detects polygons and reports its information into a CSV file. This process is made simpler by the fact that LCD screens like this are very predictable. From there, the data is imported into LibreOffice and various charts and graphs can be made.
Although perhaps not the most elegant of hacks, sometimes you have to work with the supplies that are on hand at the time. Sometimes the tools you need are too expensive, politically dangerous, or too impractical to obtain. To that end [Saulius]’s hack is a great example of what hacks are possible with the right mindset.
If you’re looking for the technology here, you won’t find much. There’s no lens, no shutter, and no electronics of any kind in [Mick Farrell] and [Cliff Haynes]’ Straw Camera. This is literally a box full of drinking straws standing on end, with a sheet of photo paper behind it. Each straw sends a spot of light that represents the average hue and luminance of its limited view of the subject directly to the film. The process of making an exposure consists of composing the scene, turning out the lights, loading the camera, and setting off a flash.
The resulting images are defocused but recognizable, like seeing familiar sights through a heavy fog. The straws make a strong texture over the ghostly image of the subject – indeed, the straws are the only thing in focus. The fact that the straws don’t form a perfect honeycomb due to settling and imperfections in the bundles is jarring at first, but as you see the images you get used to the extra texture.
When we first saw this, we wondered about the possibility of putting a simple photosensor at the bottom of each straw to capture similar images digitally. The TCS3200 would be about the right size, but given that there are about 32,000 straws in the bundle, the BOM might get a little out of hand. Still, a scaled down digital straw camera might yield some interesting images.
The ‘Pola’ in the PolaPi is a giveaway for what this Hackaday.io project is. This polaroid-like camera, created by [Muth], is a sort of black and white, blast from the past mixed with modern 3D printing. It is based on a Raspberry-pi Zero with a camera module, a Sharp memory LCD for viewing the image, and a Nano thermal printer to print the actual photo. Throw in some buttons, a battery and a slick 3D printed case and you have your own PolaPi.
Right now it’s already on the second iteration as [Muth]s gave the first prototype to some lucky person. As he had to rebuild the whole camera from scratch, he took advantage of what he learned in the first prototype and improved on it. The camera has a ‘live’ 20fps rate on the LCD and you can take your photo, review it, and if you like the shot, print it. The printed photo is surprisingly good, check it out in the video after the break.
Currently the software is being actively developed and the latest version has, among other things, a slit-scan mode. For those who don’t know, slit-scan photography is a technique that can create some crazy warped and psychedelic effects (in this case, as psychedelic as a black and white photo can be).
We know you want one for yourself. If you don’t want to spend the time installing and configuring your RPi Zero, [Muth] kindly shared an SD card image with everything ready.
Like any Moore’s Law-inspired race, the megapixel race in digital cameras in the late 1990s and into the 2000s was a harsh battleground for every manufacturer. With the development of the smartphone, it became a war on two fronts, with Samsung eventually cramming twenty megapixels into a handheld. Although no clear winner of consumer-grade cameras was ever announced (and Samsung ended up reducing their flagship phone’s cameras to sixteen megapixels for reasons we’ll discuss) it seems as though this race is over, fizzling out into a void where even marketing and advertising groups don’t readily venture. What happened?
A brief overview of Moore’s Law predicts that transistor density on a given computer chip should double about every two years. A digital camera’s sensor is remarkably similar, using the same silicon to form charge-coupled devices or CMOS sensors (the same CMOS technology used in some RAM and other digital logic technology) to detect photons that hit it. It’s not too far of a leap to realize how Moore’s Law would apply to the number of photo detectors on a digital camera’s image sensor. Like transistor density, however, there’s also a limit to how many photo detectors will fit in a given area before undesirable effects start to appear.
Image sensors have come a long way since video camera tubes. In the ’70s, the charge-coupled device (CCD) replaced the cathode ray tube as the dominant video capturing technology. A CCD works by arranging capacitors into an array and biasing them with a small voltage. When a photon hits one of the capacitors, it is converted into an electrical charge which can then be stored as digital information. While there are still specialty CCD sensors for some niche applications, most image sensors are now of the CMOS variety. CMOS uses photodiodes, rather than capacitors, along with a few other transistors for every pixel. CMOS sensors perform better than CCD sensors because each pixel has an amplifier which results in more accurate capturing of data. They are also faster, scale more readily, use fewer components in general, and use less power than a comparably sized CCD. Despite all of these advantages, however, there are still many limitations to modern sensors when more and more of them get packed onto a single piece of silicon.
While transistor density tends to be limited by quantum effects, image sensor density is limited by what is effectively a “noisy” picture. Noise can be introduced in an image as a result of thermal fluctuations within the material, so if the voltage threshold for a single pixel is so low that it falsely registers a photon when it shouldn’t, the image quality will be greatly reduced. This is more noticeable in CCD sensors (one effect is called “blooming“) but similar defects can happen in CMOS sensors as well. There are a few ways to solve these problems, though.
First, the voltage threshold can be raised so that random thermal fluctuations don’t rise above the threshold to trigger the pixels. In a DSLR, this typically means changing the ISO setting of a camera, where a lower ISO setting means more light is required to trigger a pixel, but that random fluctuations are less likely to happen. From a camera designer’s point-of-view, however, a higher voltage generally implies greater power consumption and some speed considerations, so there are some tradeoffs to make in this area.
Another reason that thermal fluctuations cause noise in image sensors is that the pixels themselves are so close together that they influence their neighbors. The answer here seems obvious: simply increase the area of the sensor, make the pixels of the sensor bigger, or both. This is a good solution if you have unlimited area, but in something like a cell phone this isn’t practical. This gets to the core of the reason that most modern cell phones seem to be practically limited somewhere in the sixteen-to-twenty megapixel range. If the pixels are made too small to increase megapixel count, the noise will start to ruin the images. If the pixels are too big, the picture will have a low resolution.
There are some non-technological ways of increasing megapixel count for an image as well. For example, a panoramic image will have a megapixel count much higher than that of the camera that took the picture simply because each part of the panorama has the full mexapixel count. It’s also possible to reduce noise in a single frame of any picture by using lenses that collect more light (lenses with a lower f-number) which allows the photographer to use a lower ISO setting to reduce the camera’s sensitivity.
Of course, if you have unlimited area you can make image sensors of virtually any size. There are some extremely large, expensive cameras called gigapixel cameras that can take pictures of unimaginable detail. Their size and cost is a limiting factor for consumer devices, though, and as such are generally used for specialty purposes only. The largest image sensor ever built has a surface of almost five square meters and is the size of a car. The camera will be put to use in 2019 in the Large Synoptic Survey Telescope in South America where it will capture images of the night sky with its 8.4 meter primary mirror. If this was part of the megapixel race in consumer goods, it would certainly be the winner.
With all of this being said, it becomes obvious that there are many more considerations in a digital camera than just the megapixel count. With so many facets of a camera such as physical sensor size, lenses, camera settings, post-processing capabilities, filters, etc., the megapixel number was essentially an easy way for marketers to advertise the claimed superiority of their products until the practical limits of image sensors was reached. Beyond a certain limit, more megapixels doesn’t automatically translate into a better picture. As already mentioned, however, the megapixel count can be important, but there are so many ways to make up for a lower megapixel count if you have to. For example, images with high dynamic range are becoming the norm even in cell phones, which also helps eliminate the need for a flash. Whatever you decide, though, if you want to start taking great pictures don’t worry about specs; just go out and take some photographs!
(Title image: VISTA gigapixel mosaic of the central parts of the Milky Way, produced by European Southern Observatory (ESO) and released under Creative Commons Attribution 4.0 International License. This is a scaled version of the original 108,500 x 81,500, 9-gigapixel image.)