PhotoTransistor Based Eye-Tracking

eyetrack

The applications of eye-tracking devices are endless, which is why we always get excited to see new techniques in measuring the absolute position of the human eye. Cornell students [Michael and John] took on an interesting approach for their final project and designed a phototransistor based eye-tracking system.

We can definitely see the potential of this project, but for their first prototype, the system relies on both eye-tracking and head movement to fully control a mouse pointer. An end-product design was in mind, so the system consists of both a pair of custom 3D printed glasses and a wireless receiver; thus avoiding the need to be tethered to the computer under control . The horizontal position of the mouse pointer is controlled via the infrared eye tracking mechanism, consisting of an Infrared LED positioned above the eye and two phototransistors located on each side of the eye. The measured analog data from the phototransistors determine the eye’s horizontal position. The vertical movement of the mouse pointer is controlled with the help of a 3-axis gyroscope mounted to the glasses. The effectiveness of a simple infrared LED/phototransistor to detect eye movement is impressive, because similar projects we’ve seen have been camera based. We understand how final project deadlines can be, so we hope [Michael and John] continue past the deadline with this one. It would be great to see if the absolute position (horizontal and vertical) of the eye can be tracked entirely with the phototransistor technique.

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Webcam Eye-tracking Moves Robot-powered Skittles Candy

robot-powered-skittles

This is a great hack, and it’s an advertisement. We wish this were the norm when it comes to advertising because they’ve really got our number. Skittles enlisted a few engineers to build a web interface that moves robot-powered candies.

When we started looking into this we figured that a few robots were covered with over-sized cases that looked like Skittles. But that’s not it at all. What you see above is actually upside down. The top side of the white surface has one tiny wheeled robot for each candy. A magnet was embedded in each Skittle which holds it to the underside of the surface. The user interface was rolled out on a Facebook page. It uses a common webcam for eye tracking. When you move your eyes, the robot controlling your assigned candy moves in that direction. See for yourself in the cllip after the break.

So we say bravo Mars Inc. We love it that you decided to show off what’s behind to curtain. As with the Hyundai pixel wall, there’s a whole subset of people who might ignore the ad, but will spend a lot of time to find out how it was done.

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Tracking Eye Movement By Measuring Electrons In The Eye

[Luis Cruz] is a Honduran High School student, and he built an amazing electrooculography system, and the writeup (PDF warning) of the project is one of the best we’ve seen.

[Luis] goes through the theory of the electrooculogram – the human eye is polarized from front to back because of a negative charge in the nerve endings in the retina. Because of this minute difference in charge, a user’s gaze can be tracked by electrodes attached to the skin around the eye. After connecting eye electrodes to opamps and a microcontroller, [Luis] imported the data with a Python script and wrote an “eyeboard” application to enable text input using only eye movement. The original goal of the project was to build an interface for severely disabled people, but [Luis] sees applications for sleep research and gathering marketing data.

We covered [Luis]’ homebrew 8-bit console last year, and he’s now controlling his Pong clone with his eye-tracking device. We’re reminded of a similar system developed by Atari, but [Luis]’ system uses a method that won’t give the user a headache after 15 minutes.

Check out [Luis] going through the capabilities of his interface after the break. Continue reading “Tracking Eye Movement By Measuring Electrons In The Eye”

Get Statistical About Your Pet With This Cat Tracking Dashboard

Cats can be wonderful companions, but they can also be aloof and boring to hang out with. If you want to get a little more out of the relationship, consider obsessively tracking your cat’s basic statistics with this display from [Matthew Sylvester].

The build is based around the Seeedstudio ReTerminal E1001/E1002 devices—basically an e-paper display with a programmable ESP32-S3 built right in. It’s upon this display that you will see all kinds of feline statistics being logged and graphed. The data itself comes from smart litterboxes, with [Matthew] figuring out how to grab data on weight and litterbox usage via APIs. In particular, he’s got the system working with PetKit gear as well as the Whisker Litter Robot 4. His dashboard can separately track data for four cats and merely needs the right account details to start pulling in data from the relevant cat cloud service.

For [Matthew], the build wasn’t just a bit of fun—it also proved very useful. When one of his cats had a medical issue recently, he was quickly able to pick up that something was wrong and seek the help required. That’s a pretty great result for any homebrew project. It’s unrelated, too, but Gnocci is a great name for a cat, so hats off for that one.

We’ve featured some other fun cat-tracking projects over the years, too. If you’re whipping up your own neat hardware to commune with, entertain, or otherwise interact with your cat, don’t hesitate to let us know on the tipsline.

Animatronic Eyes Are Watching You

If you haven’t been following [Will Cogley]’s animatronic adventures on YouTube, you’re missing out. He’s got a good thing going, and the latest step is an adorable robot that tracks you with its own eyes.

Yes, the cameras are embedded inside the animatronic eyes.That was a lot easier than expected; rather than the redesign he was afraid of [Will] was able to route the camera cable through his existing animatronic mechanism, and only needed to hollow out the eyeball. The tiny camera’s aperture sits nigh-undetectable within the pupil.

On the software side, face tracking is provided by MediaPipe. It’s currently running on a laptop, but the plan is to embed a Raspberry Pi inside the robot at a later date. MediaPipe tracks any visible face and calculates the X and Y offset to direct the servos. With a dead zone at the center of the image and a little smoothing, the eye motion becomes uncannily natural. [Will] doesn’t say how he’s got it set up to handle more than one face; likely it will just stick with the first object identified.

Eyes aren’t much by themselves, so [Will] goes further by creating a little robot. The adorable head sits on a 3D-printed tapered roller bearing atop a very simple body. Another printed mechanism allows for pivot, and both axes are servo-controlled, bringing the total number of motors up to six. Tracking prefers eye motion, and the head pivots to follow to try and create a naturalistic motion. Judge for yourself how well it works in the video below. (Jump to 7:15 for the finished product.)

We’ve featured [Will]’s animatronic anatomy adventures before– everything from beating hearts, and full-motion bionic hands, to an earlier, camera-less iteration of the eyes in this project.

Don’t forget if you ever find yourself wading into the Uncanny Valley that you can tip us off to make sure everyone can share in the discomfort.

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Open Source Tracker Keeps An Eye On Furry Friends

Most of the time, you’ll know where your cats are — asleep on the bed about 23.5 hours a day and eating or pooping the rest of the time. But some cats are more active than others, so there’s commercial options for those who want to keep tabs on their pet. Unfortunately, [Sahas Chitlange] didn’t like any of them, so he designed and built his own open source version: FindMyCat.io.

The system is in two parts: a module that fits onto a cat collar, and a home station that, well, stays at home. It offers a variety of tracking modes. In home mode, the home station signals the collar every 10 seconds, which stays in a deep sleep most of the time. If the collar doesn’t get a signal from the home station, it switches to ping mode, where it will wait for a signal from the FindMyCat over the LTE-M connection and report its location.

Finally, the app can set the collar to Lost Kitteh mode, where the collar will send a location to the app every seven minutes or thirty seconds. The collar also supports a direction-finding feature, using the ultra wideband (UWB) feature of recent Apple iPhones to point you in the direction and distance of the tracked cat.

The collar is built around a Nordic Semiconductor NRF-9160, a System in a Package (SiP) that does most of the heavy lifting as it includes GPS, an LTE-M modem, and an ARM processor. One interesting feature here: [Sahas] doesn’t make his antennas on the PCB, but instead uses an Ignion NN03-310, an off-the-shelf antenna that is already qualified for LTE-M use. That means this system can be connected to almost any LTE-M network without getting yelled at for using unqualified hardware and making the local cell towers explode.

The collar also includes a DWM3001CDK ultrawideband (UWB) module used for the locator feature. The accompanying app uses this and Apple’s UWB support to show the user which direction the cat is in, and how far away it is. The app isn’t in the Apple App Store yet, so you’ll need to sign up for an Apple Developer account to use it. We’d love to hear from anyone who takes it for a test drive with their own pet.

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A ginger cat, wearing a blue harness with a brass and wooden box on its back

Handmade GPS Tracker Keeps An Eye On Adventurous Cats

One of the most convenient things about having cats is their independent lifestyle: most are happy to enjoy themselves outside all day, only coming back home when it’s time for dinner and a nap. What your cat gets up to during the day remains a mystery, unless you fit it with a GPS collar. When [Sahas Chitlange] went searching for a GPS tracker for his beloved Pumpkin, he found that none were exactly to his liking: too slow, too big, or simply unreliable. This led him to design and build his own, called Find My Cat.

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