Taking pictures in the 21st century is incredibly easy. So easy in fact that most people don’t even own a dedicated camera; from smartphones to door bells there are cameras built into nearly electronic device we own. So in this era of ubiquitous photography, you might think that a very slow and extremely low resolution camera wouldn’t be of interest. Under normal circumstances that’s probably true, but this single pixel camera built by [Tucker Shannon] is anything but normal.
[XenonJohn] dabbles in cryptocurrency trading, and when he saw an opportunity to buy an RGB color sensor, his immediate thought — which he admitted to us would probably not be the immediate thought of most normal people — was that he could point it to his laptop screen and have it analyze the ratio of green (buy) orders to red (sell) orders being made for crypto trading. In theory, if at a given moment there are more people looking to buy than there are people looking to sell, the value of a commodity could be expected to go up slightly in the short-term. The reverse is true if a lot of sell orders coming in relative to buy orders. Having this information and possibly acting on it could be useful, but then again it might not. Either way, as far as out-of-left-field project ideas go, promoting an RGB color sensor to Cryptocurrency Trading Advisor is a pretty good one.
Since the RGB sensor only sees what is directly in front of it, [XenonJohn] assembled a sort of simple light guide. By enclosing the area of the screen that contains orders in foil-lined cardboard, the sensor can get a general approximation of the amount of red (sell orders) versus green (buy orders). The data gets read by an Arduino which does a simple analysis and sends alerts when a threshold is crossed. He dubbed it the Crypto-Eye, and a video demo is embedded below.
Digital photo frames these days require you to manage the photos stored on it or the cloud-based service tied to the frame’s manufacturer. [Henric Andersson] realized that he and his wife take a lot of photos but find little time to go through them — like photo albums of days past — and add them to any photo frame-like appliance or service. Since Google photos can do a lot of the sorting for them, he decided to incorporate that into a digital photo frame.
Using his wife’s old Viewsonic 24” 1080p monitor, he cracked it open and incorporated the screen into a 24×16 distressed wood frame — reinforcing it to account for the bulky, built-in power supply with pieces of HDF and a lot of glue. The brains behind this digital photo frame is a Raspberry Pi 3 he received from a friend. To turn the whole on/off, he built a small circuit but it turned out it wasn’t strictly necessary since everything started just fine without it.
While functionally complete, it needed one more addition. A little thing called ‘color temperature calibration’ — aka white balance.
Finding the TCS34725 RGB color sensor by Adafruit — and readily available code for easy integration — [Andersson] puzzled over how to add it to the frame. To disguise it while retaining its effectiveness, he had to glue it to the rear of the frame after drilling a hole in the top piece and sticking a plastic stick through the hole to let light through to the sensor.
To get the photos to display, [Henric Andersson] says all he did was add a few queries to Google Photos and it will display all your relevant photos that have been synced to the service. For a breakdown of that side of this hack, check out his other post with the details.
While Google Photos deftly displays photos of various orientations, sizes, and aspect ratios, we’ve featured a digital photo frame that handles the task a little differently.
With so many ways to capture images from paper, do we really need another one? Especially one that takes 15 minutes to capture a 128×128 pixel image? Probably not, but building a single-pixel RGB scanner is pretty instructive, and good clean fun to boot.
We have to admit that when [Kerry Wong] scored an ancient Hewlett-Packard X-Y chart recorder a while back, we wondered if it would lead to anything useful. One may quibble with the claim that the Lorenz attractor plotter he built with it is useful, and this single pixel scanner is equally suspect, but we like the idea. Using an Arduino to drive the X- and X-axis of the recorder through a raster pattern over the bed and replacing the pen with an RGB sensor board, [Kerry] was able to collect the color data for each pixel and reconstruct the image. It wouldn’t be too hard to replicate this if you don’t have an analog X-Y recorder, which just goes to show that not everything needs to be steppers and digital to get something useful done. Or at least semi-useful.