Two Wire Sensors On LED Strips

December 4, 2021 by Lewin Day 7 Comments

While addressable LED strips are all the rage, [Mike] from [mikeselectricstuff] has been working on an installation using the more basic two-wire strips that are simply controlled via PWM dimming. He’s recently figured out a tidy way to send sensor signals down these strips without adding any additional cabling.

Schematic for hooking up a sensor — The circuit in question.

The build uses 24 V LED tape, which consists of gangs of 6 LEDs in series with a forward voltage of 3V. Thus, these strips don’t even begin to light until approximately 18V is across them.

By adding a 15 V Zener diode and a resistor across the MOSFET which dims the LEDs, a voltage of around 9 V can be put across the LEDs without lighting them up when the MOSFET PWM dimmer is in its off phase. A PIC10F322 microcontroller and an accelerometer can then be run from this voltage, with the aid of a 3.3 V regulator wired in parallel with the LEDs. The regulator must also be able to handle the full 24 V when the LEDs are switched on.

A transistor is also wired up, switching a 2.2 K resistor in parallel with the LEDs. When turned on by the PIC, this transistor causes roughly a 10 mA current to flow through the Zener diode and its series resistor. The voltage developed across that series resistor can be measured as the transistor is turned on and off. In this case, the pulse width used to turn that transistor on is relative to motion detected by the accelerometer on the end of the LED strip.

Turning the LEDs on at 100% duty cycle prevents the system working, as the pulse widths generated by the sensor circuit can’t be detected when the LED line is held high all the time. However, in practice, it matters not — running the LEDs at a maximum 98% duty cycle eliminates the issue.

It’s an ingenious way to send sensor signals down a two-wire LED strip, even if it does take a second to wrap one’s head around it. It also seems to do a great job of adding motion-reactive effects to the LED strips in question. It’s not the first LED project we’ve seen from [Mike], either. Video after the break.

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This Week In Security: GoDaddy, Tardigrade, Monox, And BigSig

December 3, 2021 by Jonathan Bennett 10 Comments

After the Thanksgiving break, we have two weeks of news to cover, so hang on for an extra-long entry. First up is GoDaddy, who suffered a breach starting on September 6th. According to an SEC filing, they noticed the problem on November 17th, and determined that there was unauthorized access to their provisioning system for their WordPress hosting service. For those keeping track at home, that’s two months and eleven days that a malicious actor had access. And what all was compromised? The email address and customer number of the approximate 1.2 million GoDaddy WordPress users; the initial WordPress password, in the clear; the SFTP and database passwords, also in the clear; and for some customers, their private SSL key.

The saving grace is that it seems that GoDaddy’s systems are segregated well enough that this breach doesn’t seem to have led to further widespread compromise. It’s unclear why passwords were stored in the clear beyond the initial setup procedure. To be safe, if you have a WordPress instance hosted by GoDaddy, you should examine it very carefully for signs of compromise, and rotate associated passwords. The SSL keys may be the most troubling, as this would allow an attacker to impersonate the domain. Given the length of time the attack had access, it would not surprise me to learn that more of GoDaddy’s infrastructure was actually compromised. Continue reading “This Week In Security: GoDaddy, Tardigrade, Monox, And BigSig” →

Image Credit: https://3dp.se/2018/04/17/3dmeetup-lockade-entusiaster-i-alla-aldrar/

Remembering Sanjay Mortimer, Pioneer And Visionary In 3D Printing

December 1, 2021 by Sonya Vasquez 24 Comments

Over the weekend, Sanjay Mortimer passed away. This is a tremendous blow to the many people who he touched directly and indirectly throughout his life. We will remember Sanjay as pioneer, hacker, and beloved spokesperson for the 3D printing community.

If you’ve dabbled in 3D printing, you might recall Sanjay as the charismatic director and co-founder of the extrusion company E3D. He was always brimming with enthusiasm to showcase something that he and his company had been developing to push 3D printing further and further. But he was also thoughtful and a friend to many in the community.

Let’s talk about some of his footprints.

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Korean Facial Recognition Project Faces Opposition

December 1, 2021 by Chris Lott 20 Comments

It was discovered last month that a South Korean government project has been providing millions of facial images taken at Incheon International Airport to private industry without the consent of those photographed. Several civic groups called this a “shocking human rights disaster” in a 9 Nov press conference, and formally requested that the project be cancelled. In response, the government has only promised that “the project would be conducted at a minimum level to ensure personal information is not abused”. These groups are now planning a lawsuit to challenge the project.

Facial information and other biometric data aren’t easily altered and are unique to the individuals concerned. If this data were to be leaked, it would constitute a devastating infringement upon their privacy. It’s unheard of for state organizations — whose duty it is to manage and control facial recognition technology — to hand over biometric information collected for public purposes to a private-sector company for the development of technology.

The program itself wasn’t secret, and had been publicly announced back in 2019. But the project’s scope and implementation weren’t made clear until a lawmaker recently requested documents on the project from the responsible government agencies. The system, called the Artificial Intelligence and Tracking System Construction Project, was a pilot program set to run until 2022. Its goals were to simplify the security and immigration screening of passengers, improve airport security, and to promote the local AI industry in South Korea. If the project proves successful, the plan is to expand it to other airports and ports in the country.

Current systems at the airport do one-to-one facial recognition. For example, they try to determine whether the face of the person presenting a passport matches the photo in the passport. The goal of this new project was to develop one-to-many matching algorithms, which can match one face against the plethora of faces in an airport, track the movement of a face within the airport, and flag “suspicious” activities which could be a security concern.

The groups protesting the project note that the collection and sharing of these images without the travelers’ consent is prohibited by the Personal Information Protection Act, the South Korean law which governs such things. Under this act, a project like this would ordinarily require consent of the participants. But the government’s interpretation relies on an exception in the act, specifically, Article 15 Section 3, which states:

A personal information controller may use personal information without the consent of a data subject within the scope reasonably related to the initial purpose of the collection

Basically they are saying that since the images were collected at the security and immigration checkpoints, and that the project will be using them to improve the security and immigration checkpoints, no consent is required.

Foreigners: 120 million individuals, face image, nationality, gender, age
Korean citizens: 57.6 million individuals, face image, nationality, gender, age
Other: unknown number of individuals, images and videos of atypical behavior and travelers in motion

The breakdown of the numbers above reveals that 57 million Korean citizens are in the data set, a bit surprising to many since the collection of biometric data on Korean citizens at immigration is prohibited by law. The project circumvented this by only collecting data from citizens who participate in the automated Smart Entry service, a voluntary program which uses fingerprints and facial recognition. It’s interesting to note that the number of passengers using Incheon airport since May 2019 (the program was announced 30 Apr 2019) is only 62 million, so the average passenger appears approximately three times in the data set.

Are there any similar programs in your region? How do they handle the issue of consent, if at all? Let us know in the comments below.

[Banner image: “Customer uses facial recognition as identification at TSA security checkpoint” by DeltaNewsHub, CC BY 2.0 — Yes, it’s from another country with similar problems, but much less public outcry. Discuss in the comments!]

Samsung Bricks Smart TVs

November 29, 2021 by Chris Lott 247 Comments

Earlier this Fall, a Samsung warehouse in South Africa was robbed and the thieves got away with a quantity of smart televisions. Samsung proceeded to implement a little-known feature called “TV Block” which is installed on all of their TV products. The serial numbers of the stolen TV sets are flagged in their servers, and if one of these sets tries to connect the internet in the future, it will recognize that it is stolen and proceed to brick itself, disabling all television functionality.

So while this real-life scenario makes sense, it is a bit alarming to realize the implication of such a feature — the manufacturer can reach into your TV and disable it from afar. One can assume that Samsung won’t abuse this capability, because acting otherwise would harm their reputation. In a press release, Samsung announced that any consumers whose sets were incorrectly bricked can have their sets un-bricked after demonstrating proper ownership.

Despite such good intentions, the mere existence of such a feature is worrisome. What someone hacks the system and begins bricking TVs all over the world willy-nilly? If you are concerned about this possibility, one option of course is to never connect your TV set to the internet. But in that case, it might be better to just buy a “dumb” television set instead.

Anti-theft immobilizers are not new — one system was patented over 100 years ago to thwart car thieves. Car stereo systems have also long featured technology that renders them unusable when stolen. Although this robbery brought Samsung’s “TV Block” to consumers’ attention, we wonder if other manufacturers have similar anti-theft systems which aren’t well publicized. If you know of any, please share in the comments below.

This Raspberry Pi Mini ITX Board Has Tons Of IO

November 28, 2021 by Lewin Day 27 Comments

The Raspberry Pi now comes in a wide variety of versions. There are tiny little Zeros, and of course the mainstream-sized boards. Then, there’s the latest greatest Compute Module 4, ready to slot on to a carrier board to break out all its IO. The Seaberry is one such design, as demonstrated by [Jeff Geerling], giving the CM4 a Mini ITX formfactor and a ton of IO. (Video embedded after the break.)

The Seaberry sports a full-sized x16 PCI-E port, with only 1x bandwidth but capable of holding full-sized cards. There’s also four mini-PCI-E slots along the top, with four M.2 E-key slots hiding underneath. The board then has a M.2 slot in the middle for NVME drives, and x1 PCI-E slot hanging off the side.

Ports include a USB 2.0, a Cisco-style serial console port, two HDMI ports, and a Gigabit Ethernet jack. Two seperate 12V connectors are provided allowing for a redundant power supply setup, which can be made triple redundant with the addition of the right Power-over-Ethernet hardware. Naturally, the Seaberry also features the usual 40-pin GPIO header, the 14-pin CM4 IO header, as well as the usual DSI, CSI and RTC hookups.

The Mini ITX design is a particular boon. The Seaberry can easily be slapped into a mini PC case, and the power button and activity LEDs work just like you’d expect.

In testing the board, [Jeff Geerling] filled up almost every slot, trying to see how many cards will run on an Compute Module 4 with 8GB of RAM. Throwing in an NVME SSD drive, several Coral TPUs for machine learning, multiple network cards and a SATA interface caused no problems.

Not everything worked due to driver limitations, but everything enumerated on the bus just fine. [Jeff’s] earlier work paid dividends here. His previous attempts trying to get GPUs working on the platform meant opening up an extended BAR space for PCI devices wasn’t a problem.

Further attempts involved adding in a 12-card carrier loaded up with 7 more TPUs, 5 more WiFi cards, and 3 more NVME drives. Outside of some kernel panics from excess NVME drives, the Pi CM4 was still able to detect everything, showing it can address more than 20 PCI-E devices without major issues.

Throwing so many devices at the Pi CM4 may not have an obvious application in the mainstream, but it’s sure to prove useful to someone. We’re certainly enjoying watching [Jeff] push the limits of what’s possible with the CM4, and we hope he gets GPUs working soon.

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Arduino Plays The Glasses

November 22, 2021 by Al Williams 8 Comments

Have you ever been on a city street and seen a busker playing music on glasses? Each glass has a different amount of water and produces a different note when tapped. [Cyberlab] must have seen them and created an Arduino robot to play tunes on glasses. You can see the result in the video below.

If we had done this, we might have had a solenoid per glass or used some linear component like a 3D printer axis to pick different glasses. [Cyberlab] did something smarter. The glasses go in a circle and a stepper motor points at the correct glass and activates a solenoid. The result is pretty good and it is a lot simpler than any of our ideas.

If you aren’t musically inclined, you might wonder how you’d program the songs. There’s an example of taking a music box score from a website — apparently, there are lots of these — and removing any polyphony from it. The site mentioned even has an editor where you can import MIDI files and work with them to produce a music box strip that you could then convert. Then you encode each note as a number from 0 to 6.

Of course, you also have to fill your glasses with the right amount of water. A piano tuning phone app should be useful. We’ve seen this done in a linear fashion before. You can even use a single glass for many notes with a little ingenuity.

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