[Bruce Helsen] built this dual axis solar tracker as one of his final projects for school.
As can be experimentally verified in a very short timeframe, the sun moves across the sky. This is a particularly troublesome behavior for solar panels, which work best when the sun shines directly on them. Engineers soon realized that abstracting the sun away only works in physics class, and moved to the second best idea of tracking sun by moving the panel. Surprisingly, for larger installations the cost of adding tracking (and its maintenance) isn’t worth the gains, but for smaller, and especially urban, installations like [Bruce]’s it can still help.
[Bruce]’s build can be entirely sourced from eBay. The light direction is sensed via a very clever homemade directional light sensor. A 3D printer extruded cross profile sits inside an industrial lamp housing. The assembly divides the sky into four quadrants with a light-dependent resistor for each. By measuring the differences, the panel can point in the optimal direction.
The panel’s two axis are controlled with two cheap linear actuators. The brains are an Arduino glued to a large amount of solar support electronics and the online energy monitor component is covered by an ESP8266.
The construction works quite well. If you’d like to build one yourself the entire BOM, drawings, and code are provided on the instructables page.
First there were text games, then came 2D dungeons. When Wolfenstein 3D broke out on the gaming scene, it created quite a fuss. But if all you’ve got is a strip of WS2812 LEDs, those are a few dimensions too many.
[treibair] has started up a project on Hackaday.io to start working on 1D video games to be played on a single LED strip. While the end application is something with a cool physical interface, probably driven by a microcontroller, prototyping is a lot easier on the big computer. He’s writing it in Processing, though, so that the transition to the Arduino is easier in the end.
Check out the video below.
There are a couple of other games out there in 1D, including Line Wobbler (YouTube) and, naturally, Wolfenstein 1D. We even saw a one-dimensional “snake” clone at Make Munich a few months back. (Would the author please stand up?)
We think the idea is a good one, and lining up everyone’s 1D gaming experience in one place would be a great help. So link up code and reviews in the comments!
Continue reading “Video Games In As Few Dimensions As Possible”
Building an electric motor from a coil of wire, some magnets, and some paper clips is a rite of passage for many budding science buffs. These motors are simple brushed motors. That is, the electromagnet spins towards a permanent magnet and the spinning breaks the circuit, allowing the electromagnet to continue spinning from inertia. Eventually, the connection completes again and the cycle starts over. Real brushed motors commutate the DC supply current so that the electromagnet changes polarity midway through the turn. Either way, the basic design is permanent magnets on the outside (the stationary part) and electromagnets on the inside (the rotating part).
Brushless motors flip this inside out. The rotating part (the rotor) has a permanent magnet. The stationary part (the stator) has multiple electromagnets. By controlling the electromagnets, the rotor spins. With no brushes, these motors are often more efficient, they don’t generate as much electrical noise, and there is no danger of brushes wearing out. In addition, the electromagnets staying put make the motor easier to wire and, if needed, easier to cool the electromagnets. The principle of operation is similar to a stepper motor. Steppers are usually optimized for small precise steps. Brushless motors are optimized for spinning, not stepping.
[Axbm] built a clever brushless motor out of little more than PVC pipe, some magnets, wire, and iron rods. The plan is simple: construct a PVC frame, build a rotor out of PVC and magnets, and mount electromagnets on the frame. An Arduino and some FETs drive the coils, although you could drive the motors using any number of methods. You can see the whole thing work in the video below.
Continue reading “Build Your Own Brushless Motor”
Blood glucose monitors are pretty ubiquitous today. For most people with diabetes, these cheap and reliable sensors are their primary means of managing their blood sugar. But what is the enterprising diabetic hacker to do if he wakes up and realizes, with horror, that a primary aspect of his daily routine doesn’t involve an Arduino?
Rather than succumb to an Arduino-less reality, he can hopefully use the shield [M. Bindhammer] is working on to take his glucose measurement into his own hands.
[Bindhammer]’s initial work is based around the popular one-touch brand of strips. These are the cheapest, use very little blood, and the included needle is not as bad as it could be. His first challenge was just getting the connector for the strips. Naturally he could cannibalize a monitor from the pharmacy, but for someone making a shield that needs a supply line, this isn’t the best option. Surprisingly, the connectors used aren’t patented, so the companies are instead just more rigorous about who they sell them to. After a bit of work, he managed to find a source.
The next challenge is reverse engineering the actual algorithm used by the commercial sensor. It’s challenging. A simple mixture of water and glucose, for example, made the sensor throw an error. He’ll get it eventually, though, making this a great entry for the Hackaday Prize.
In order to resolve the problem of congestion at the entrance to their hackerspace, the minds at i3Detroit installed a motion-activated mechanical iris in their door’s porthole.
Grabbing the design online (which they are now hosting on their site here), the parts were laser cut out of wood, gold leaf was added for effect, and it was relatively easy to assemble. PIR sensors detect movement on both sides of the door and an FET resistor connected to an orange LED add some old-school science fiction flair. The iris is actuated by a 12V car window motor — which works just fine on the 5V power that it’s supplied with — and an Arduino filling in as a controller. Start and stop positioning required some limit switches that seem to do the trick.
Continue reading “Door Iris Porthole is the Perfect Fix for Detroit Hackerspace”
Necessity is the mother of invention, but sometimes frustration is as good a motivator. [Maciej] does a bunch of statistics in his day job using SPSS. Like most complicated pieces of software, it can get hung, and the only way to stop it is to manually kill the running processes. Apparently, that happened one time too many for [Maciej].
He took matters into his own hands, repurposing a big red emergency-stop button for the task. It’s mounted on a jar, and the microcontroller inside is configured as a USB keyboard. When he mashes the button, it opens the “Run…” menu and types out
taskkill spssengine.exe for him.
We can totally see the therapeutic value of such a device. Plus, in case SPSS is gobbling up his system memory and everything’s approaching standstill, the vital seconds saved by the microcontroller’s quick-typing fingers could be a lifesaver.
[Sergey Mironov] sent in his SelfieBot project. His company, Endurance Robots, sells a commercial version of the bot, which leads us to believe that in a strange and maybe brilliant move he decided to just sell the prototype stage of the product development as a kit. Since he also gave away the firmware, STLs, BOM, and made a guide so anyone can build it, we’re not complaining.
The bot is simple enough. Nicely housed hobby servos in a 3D printed case take care of the pan and tilt of the camera. The base of the bot encloses the electronics, which are an Arduino nano, a Bluetooth module, and the support electronics for power and motor driving.
To perform the face tracking, the build assumes you have a second phone. This is silly, but isn’t so unreasonable. Most people who’ve had a smart phone for a few years have a spare one living in a drawer as back-up. One phone runs the face tracking software and points the bot, via Bluetooth, towards the user. The other phone records the video.
The bot is pretty jumpy in the example video, but this can be taken care of with better motors. For a proof-of-concept, it works. A video of it in action after the break.
Continue reading “Hackaday Prize Entry: Selfie Bot Let’s You Vlog Hands Free”