DIY USB Spectrometer Actually Works

image of diy spectrometer

When we hear spectrometer, we usually think of some piece of high-end test equipment sitting in a CSI lab. Sure, a hacker could make one if he or she put their mind to it. But make one out of a webcam, some cheap diffraction grating purchased off ebay and some scrap? Surely not.

[Renaud] pulls off this MacGyver like build with a detailed knowledge of how spectrometers work. A diffraction grating is used to split the incoming light into its component wavelengths. Much like a prism would. The wavelengths then make their way through a slit, which [Renaud] made from two pieces of highly polished brass, so the webcam sensor can see a specific wavelength. While the spectrometer-from-webcam concept isn’t new,  the build is still impressive.

Once the build was complete, [Renaud] put together some software to make sense of the data. Though a bit short on details, we hope this build will inspire you to make your own spectrometer, and document it on hackaday.io of course.

A 3D(ollar) Scanner

scanner

Once you have a 3D printer, making copies of objects like a futuristic Xerox machine is the name of the game. There are, of course, 3D scanners available for hundreds of dollars, but [Joshua] wanted something a bit cheaper. He built his own 3D scanner for exactly $2.73 in parts, salvaging the rest from the parts bin at his local hackerspace.

[Josh]’s scanner is pretty much just a lazy suzan (that’s where he spent the money), with a stepper motor drive. A beam of laser light shines on whatever object is placed on the lazy suzan, and a USB webcam feeds the data to a computer. The build is heavily influenced from this Instructables build, but [Josh] has a few tricks up his sleeve: this is the only laser/camera 3D scanner that can solve a point cloud with the camera in any vertical position. This potentially means algorithmic calibration, and having the copied and printed object come out the same size as the original. You can check out that code on the git.

Future improvements to [Josh]’s 3D scanner include the ability to output point clouds and STLs, meaning anyone can go straight from scanning an object to slicing it for a 3D printer. That’s a lot of interesting software features for something that was basically pulled out of the trash.

An Automated Flappy Bird Player

game Flappy Bird has been ported to just about every system imaginable, including but not limited to the Apple II, Commodores, pretty much every version of the Atari, and serves as a really great demonstration of the TI-99’s graphics capabilities. Porting is one thing, but having a computer automate Flappy Bird is another thing entirely. [Ankur], [Sai], and [Ackerly] in [Dr. Bruce Land]’s advanced microcontroller design class at Cornell have done just that. They’re playing Flappy Bird with a camera, FPGA, and a penny wired up to a GPIO pin to guide the little 8-bit-bird through Mario pipes.

The setup the team is using consists of a webcam that records the screen of a smartphone, an FPGA, and a little bit of circuitry to emulate screen taps. Inside the FPGA, the team is looking at the video stream from the phone to detect the bird, pipes, and gaps. The ‘tapper’ unit is a US penny, placed right above the ‘tap’ button, wired to a GPIO port. This was found to be the ideal contact for a capacitive touch screen – taps that were too small weren’t registered, and taps that were too big registered as two taps.

For spending an entire semester on automating Flappy Bird, the team has a lot of knowledge to show for it, but not the high score: the bird only makes it through the first pipe 10% of the time, and the second pipe 1% of the time. The high score is three. That’s alright – getting the algorithm right to play the game correctly was very, very difficult, and to nail that problem down, they estimate it would take at least another semester.

A DIY Geomagnetic Observatory

Magnetometer observatory

[Dr. Fortin] teaches physics at a French High School, and to get his students interested in the natural world around them, he built a geomagnetic observatory, able to tell his students if they have a chance at seeing an aurora, or if a large truck just drove by.

We’ve seen this sort of device before, and the basic construction is extremely similar – a laser shines on a mirror attached to magnets. When a change occurs in the local magnetic field, the mirror rotates slightly and the laser beam is deflected. Older versions have used photoresistors, but [the doctor] is shining his laser on a piece of paper and logging everything with a webcam and a bit of OpenCV.

The design is a huge improvement over earlier DIY attempts at measuring the local magnetic field, if only because the baseline between the webcam and mirror are so long. When set up in his house, the magnetometer can detect cars parked in front of his building, but the data he’s collecting (French, but it’s just a bunch of graphs) is comparable to the official Russian magnetic field data.

Smart Hat Puts Your Head in the Game

man wearing a diy head mounted display

 

[Arvind] has dropped his hat in the game of head mounted displays. With Google Glass pushing $1,500, it’s only natural for hackers to make a cheaper alternative. [Avind’s] $80 version might not be pretty, but it gets the job done.

Using a Raspberry Pi loaded with speech recognition software, a webcam, 2.5 inch LCD display and a handful of other parts, [Arvind’s] hat mounted display allows him to view email, Google Maps, videos or just about anything he wants.

An aspheric loupe magnifier lens lets him see the display even though it sits around 5cm from his eye. No outside light is allowed in. Only the guts of the webcam were used to give him the video and microphone. We’ve seen other head mounted displays before, and this one adds to the growing collection. Be sure to check out [Arvinds] site for a tutorial on how to build your own, and catch a video of it in action after the break.

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Hacking An Old Parallel Port Webcam To Work With A Gameduino 2

connecting parallel port web camera to gameduino 2

[Andrew] couldn’t pass up a 20ish year old parallel port based webcam he saw on the shelf at a thrift store. It’s a Connectix QuickCam and was the first webcam that did not require a separate video input card to interface with your computer. Due to this feature, the webcam was extremely popular, so popular that Logitech ended up buying Connectix and marketing the camera for themselves.

It’s tough to find a newer computer that still has a parallel port, but using an old computer wasn’t [Andrew]’s plan anyways. After thinking about it, he decided to try to get the camera’s image to display on a Gameduino 2.

The hardware list is fairly minimal. The cam’s parallel connector is plugged straight into STM32 Nucleo development board by way of several jumpers. The Gameduino 2 is connected to the dev board and a USB to PS/2 adapter was made to power the camera.

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A Webcam Based Posture Sensor

Webcam based posture sensor

Even for hobby projects, iteration is very important. It allows us to improve upon and fine-tune our existing designs making them even better. [Max] wrote in to tell us about his latest posture sensor, this time, built around a webcam.

We covered [Max’s] first posture sensor back in February, which utilized an ultrasonic distance sensor to determine if you had correct posture (or not). Having spent time with this sensor and having received lots of feedback, he decided to scrap the idea of using an ultrasonic distance sensor altogether. It simply had too many issues: issues with mounting the sensor on different chairs, constantly hearing the clicking of the sensor, and more.  After being inspired by a very similar blog post to his original that mounted the sensor on a computer monitor, [Max] was back to work. This time, rather than using an ultrasonic distance sensor, he decided to use a webcam. Armed with Processing and OpenCV, he greatly improved upon the first version of his posture sensor. All of his code is provided on his website, be sure to check it out and give it a whirl!

Iteration leads to many improvements and it is an integral part of both hacking and engineering. What projects have you redesigned or rebuild? Let us know!