Real Time Video Anonymizer

If you’re wondering, Cornell is just like every other university in one respect: the grad students are starving, and wherever there is free food, students circle like vultures. The engineering and CS departments have a mailing list alerting people to free food, but a more automated solution was desired. The first web cam ever was used to notify grad students if a coffee pot was full, but Cornell shot down this idea on the basis of privacy concerns.

It’s final project time for [Bruce Land]’s courses, and a project by [Ferian Chen] and [Sean Ogden] solved the privacy concerns of a webcam in a kitchen. It’s a real-time video anonymizer, that can also be used to livestream ransom demands if you’re so inclined.

There are actually two parts to this project. The first part pixellates faces and any other skin tone, just like you’d see on a true crime TV show. This part of the project was based on an FPGA-based face detection project. ‘Skin’ pixels are defined as having a difference between the red and green channels within a certain range. With the right lighting, it works very well.

You can identify someone with their voice, too, so [Ferian] and [Sean] also made efforts to disguise hungry student’s voices as well. This was done with a phase vocoder that changes the pitch of someone’s voice, but not the spectral characteristics. The result should have been an audio channel that can’t be pinned down to one person, but is still recognizable as speech. The audio processing didn’t work as intended, with noticeable artifacts in the output. There’s still some work to be done, and now that [Ferian] and [Sean] aren’t checking the kitchen every ten minutes, the might have the time to do it.

An Open Source, DIY Digitizer

When you look at the current methods of scanning 2D and 3D objects available today, you’re basically looking at an imaging process. Either you take a picture of a 2D object, or you grab a blob of point clouds with a 3D scanner and make a 3D object that way. It wasn’t always like this – real, hardware 3D digitizers were used all the way back in the 70s, and touch probes are standard equipment on high-end CNC machines.

[Nikolaj Møbius] needed a way to record points in physical space, and not wanting to deal with the problems of images, he made an open source DIY digitizer. It’s basically a laser cut arm with rotary encoders at each joint. By reading the rotary encoders with an Arduino, [Nikolaj] can digitize a few points on a workpiece – just enough to make a bracket, or find the critical dimensions of a part.

It’s a great tool for when you need a little more information than a set of calipers can provide, and a great example of some ancient tech made useful again.

Continue reading “An Open Source, DIY Digitizer”

Hackaday Prize Entry: Density Altitude Gauge

Despite what extraordinarily overpowered quadcopters suggest, the air pressure of whatever a flying machine flys at is extremely important. Pressure is dependent on altitude and temperature, and there are hundreds of NTSB investigations that have concluded density altitude – pressure altitude corrected for nonstandard temperature variations – was the reason for a crash. Normally density altitude is computed through a slide rule or a flight computer, with the pilot entering in altitude and temperature, but somehow accidents still happen. For his entry to The Hackaday Prize, [Neil McNeight] is building an automated density altitude calculator to automate the process entirely.

Instead of having a pilot enter the altitude and temperature into a flight computer manually, [Neil]’s device grabs the current altitude from a GPS unit, and reads the temperature with a tiny sensor acquired from SparkFun. With just a little bit of math, this device will spit out the altitude an airplane or ‘copter thinks it’s at.

While the FAA won’t allow instruments that are cobbled together on a breadboard, this does have a few applications in the RC world. There are extremely high performance racing quadcopters out there now, and knowing how the craft will perform before flying it will save a few props.

The 2015 Hackaday Prize is sponsored by:

An Introduction To Valve’s Tracking Hardware

[Alan Yates] brought a demo of Valve’s new VR tech that’s the basis of the HTC Vive system to Maker Faire this year. It’s exceptionally clever, and compared to existing VR headsets it’s probably one of the best headtracking solutions out there.

With VR headsets, the problem isn’t putting two displays in front of the user’s eyes. The problem is determining where the user is looking quickly and accurately. IMUs and image processing techniques can be used with varying degrees of success, but to do it right, it needs to be really fast and really cheap.

[Alan] and [Valve]’s ‘Lighthouse’ tracking unit does this by placing a dozen or so IR photodiodes on the headset itself. On the tracking base station, IR lasers scan in the X and Y axes. By scanning these IR lasers across the VR headset, the angle of the headset to the base station can be computed in just a few cycles of a microcontroller. For a bunch of one cent photodiodes, absolute angles and the orientation to a base station can be determined very easily, something that has some pretty incredible applications for everything from VR to robotics.

Remember all of the position tracking hacks that came out as a result of the Nintendo Wii using IR beacons and a tracking camera? This seems like an evolutionary leap forward but in the same realm and can’t wait to see people hacking on this tech!

Hackaday Prize Entry: Open Source Hydroponic Monitoring System

A few months ago, [Adam] was building a controller system for a small hydroponic system he had set up in his basement. Since then, the Hackaday Prize was announced, and given the theme – saving the world one plant at a time – he’s renvisioning his garden control and monitoring system as a Hackaday Prize entry.

While the mechanical and green part of the build is exactly what you would expect from something designed from hardware store parts, the electronics are rather interesting. All the plants in either a hydroponic or dirt-based setup will have their moisture level and PH monitored by a a set of electronics that push data up to the cloud.

The current hardware setup includes a DyIO, a very cool dev platform with 24 digital I/Os and 24 servo outputs, a Raspberry Pi, and a few module boards loaded up with ARM microcontrollers and an ESP8266. [Adam] is hitting all the hardware on this build.

So far, [Adam] has a few boards sent out to a board fab, including an analog sensor module, a digital sensor module. a WiFi module hub, and a few bits and bobs that make integration into an existing garden or hydroponic setup easier. It’s a great project for this year’s Hackaday Prize, and proof that you don’t need to come up with a new build to submit something.

The 2015 Hackaday Prize is sponsored by:

Hackaday Links: May 17, 2015

Here’s a worthwhile Kickstarter for once: the Prishtina Hackerspace. Yes, that’s a Kickstarter for a hackerspace in Kosovo. Unlike most hackerspace Kickstarters, they’re already mostly funded, with 20 days to go. If we ever get around to doing the Istanbul to Kaliningrad hackerspace tour, we’ll drop by.

Codebender is a web-based tool that allows you to code and program an Arduino. The Chromebook is a web-based laptop that is popular with a few schools. Now you can uses Codebender on a Chromebook. You might need to update your Chromebook to v42, and there’s a slight bug in the USB programmers, but that should be fixed in a month or so.

Here’s a great way to waste five minutes. It’s called It’s a multiplayer online game where you’re a cell, you eat dots that are smaller than you, and bigger cells (other players) can eat you. [Morris] found the missing feature: being able to find the IP of a server so you can play with your friends. This feature is now implemented in a browser script. Here’s the repo.

The FAA currently deciding the fate of unmanned aerial vehicles and systems, and we’re going to live with any screwup they make for the next 50 years. It would be nice if all UAV operators, drone pilots, and everyone involved with flying robots could get together and hash out what the ideal rules would be. That’s happening in late July thanks to the Silicon Valley Chapter of AUVSI (Association for Unmanned Vehicle Systems International).

SOLAR ROADWAYS!! Al Jazeera is reporting a project in the Netherlands that puts solar cells in a road. It’s just a bike path, it’s only 70 meters long, and it can support at least 12 tonnes (in the form of a ‘fire brigade truck’). There’s no plans for the truly dumb solar roadways stuff – heating the roads, or having lanes with LEDs. We’re desperately seeking more information on this one.

Vintage Computers At Maker Faire

It’s no secret that Maker Faire is highly geared toward the younger crowd. This doen’t mean the Faire is completely devoid of the historic; the Bay Area Maker Faire is right in the heart of the beginnings of the computer industry, and a few of the booths are showing off exactly how far computers have come over the last forty years.

Superboard[Vince Briel] of Briel Computers has a booth showing off his wares, mostly modern reimaginings of vintage computers. His table is loaded up with replica 1s, a board that’s much smaller but still completely compatible with the Apple I. The MicroKIM made an appearance, but the crown jewel is [Vince]’s Superboard III, a replica of the Ohio Scientific Superboard II. It’s your basic 6502 computer with 32k of RAM, but unlike just about every other modern retrocomputer out there, [Vince] put the keyboard right on the main board.

The switches are Cherry MX, the keys are from WASDkeyboards. [Vince] is actually getting a lot of interest in making modern ASCII keyboards to replace the old and busted boards that came in the home computers of the 70s and 80s. That might be a project [Vince] will release sometime in the future.

[Jef Raskin], the Swift Card, and the Canon Cat

[Steve Jobs] may have been the father of the Macintosh, but he was, by no means, solely responsible for the Mac. It was a team of people, and when you talk about the UI of the Mac, the first name that should come up is [Jef Raskin].

One of [Jef Raskin]’s finest works was the Swyft Card, an add-on to the Apple II that was basically just a ROM card that had an OS and Forth interpreter on it. The distinguishing feature of the Swyft card was the use of ‘leap’ keys, a simple way to change contexts when using the computer. We’ve seen replicas of the Swyft card before, courtesy of [Mike Willegal] at the Vintage Computing Festival East.

Woodie[Dwight Elvey] of the forum brought a few extra special items related to [Raskin] and the Canon Cat. The first was a Swyft card installed in an Apple IIe. The second was a prototype Swyft computer, with SERIAL NUMBER 1 printed on a Dymo label and fixed to the case.

The ‘woodie’, as [Dwight] calls it, has two 1.44 MB disk drives, of which half of the disk is actually usable. [Dwight] didn’t take the machine apart, but I’m 99% sure the CRT in it is the exact same tube found in early 9″ Macs.

Also in [Dwight]’s display is a production Swyft computer and a Canon Cat, the final iteration of [Jef Raskin]’s idea of what a text-based computer should be.

The vintage-computer booth also had a few interesting retrocomputers including a Commodore 128D, the Apple made, Bell & Howell branded Apple II, and an Amiga 2000. Right next door was the Computer History Museum, who brought a very kid-friendly storage medium display. Showing a 10-year-old an 8″ disk is fun.