Hackaday Links: December 29, 2019

The retrocomputing crowd will go to great lengths to recreate the computers of yesteryear, and no matter which species of computer is being restored, getting it just right is a badge of honor in the community. The case and keyboard obviously playing a big part in that look, so when a crowdfunding campaign to create new keycaps for the C64 was announced, Commodore fans jumped to fund it. Sadly, more than four years later, the promised keycaps haven’t been delivered. One disappointed backer, Jim Drew, decided he was sick of waiting, so he delved into the world of keycaps injection molding and started his own competing campaign. Jim details his adventures in his Kickstarter Indiegogo campaign, which makes for good reading even if you’re not into Commodore refurbishment. Here’s hoping Jim has better luck than the competition did.

Looking for anonymity in our increasingly surveilled world? You’re not alone, and in fact, we predict facial recognition spoofing products and methods will be a growth industry in the new decade. Aside from the obvious – and often illegal – approach of wearing a mask that blocks most of the features machine learning algorithms use to quantify your face, one now has another option, in the form of a colorful pattern that makes you invisible to the YOLOv2 algorithm. The pattern, which looks like a soft-focus crowd scene rendered in Mardi Gras colors, won’t make the algorithm think you’re someone else, but it will prevent you from being classified as a person. It won’t work with any other AI algorithm, but it’s still an interesting phenomenon.

We saw a great hack come this week about using an RTL-SDR to track down a water leak. Clayton’s water bill suddenly skyrocketed, and he wanted to track down the source. Luckily, his water meter uses the encoder receive-transmit (ERT) protocol on the 900 MHz ISM band to report his usage, so he threw an SDR dongle and rtlamr at the problem. After logging his data, massaging it a bit with some Python code, and graphing water consumption over time, he found that water was being used even when nobody was home. That helped him find the culprit – leaky flap valves in the toilets resulting in a slow drip that ran up the bill. There were probably other ways to attack the problem, but we like this approach just fine.

Are your flex PCBs making you cry? Friend of Hackaday Drew Fustini sent us a tip on teardrop pads to reduce the mechanical stress on traces when the board flexes. The trouble is that KiCad can’t natively create teardrop pads. Thankfully an action plugin makes teardrops a snap. Drew goes into a bit of detail on how the plugin works and shows the results of some test PCBs he made with them. It’s a nice trick to keep in mind for your flexible design work.

25 thoughts on “Hackaday Links: December 29, 2019

    1. Biggest drawback of Eagle is their limited geometry of pads and options. If you need some odd shaped pads, you are SOL. One can get by drawing, but that causes a lot of DRC errors when used in a footprint.
      Circular traces should be used for corners in flex PCB.

      Disclaimer: I haven’t bother with upgrades to autocad version due to licensing changes.

  1. If either valve in a toilet leaks, water fills and goes down the drain at a constant rate after filling the tank to overflow pipe. Food dye in tank will show tank flush valve leakage into bowl. Rise from full to overflow will show tank fill valve leakage over time. Of course both usually happen to leak. Toilets can be a big waste of water and time spent fixing them. A PITA. Why do we allow the sale of old fashioned rubber valves in tanks? They have a short life and then become wasteful. Silicone! Water waste is bad anywhere.

    In Canada they must want to register the amount of peak water usage after a local hockey game, eh?

    1. They are cheaper and smaller than the large siphon systems we used to have in the UK. These failed closed. The ball float could fail open but this was a 5 minute fix.
      The amount of wasted water in the direct seal cisterns must be enormous…

  2. ” After logging his data, massaging it a bit with some Python code, and graphing water consumption over time, he found that water was being used even when nobody was home.”

    There’s an indicator on our water meter that shows if there’s water still flowing if everything downstream is shut off. Used to show that my ‘fix’ actually fixed the problem.

  3. “often illegal – approach of wearing a mask”

    Am I the only one who is skeptical of this? Or surprised by it? How and where and when would it be illegal to wear a mask (obviously other than one intended to impersonate another with malicious intent)? Or am I just that sheltered?

    1. For example, it’s often illegal to wear a mask during a protest in the vicinity of (or, more often, while participating in) a protest. You can see how in i.e. Hong Kong, entire districts could be considered “time and place where protest is happening”.

      1. Thanks for that. Learn something every day. I had not considered the protest situations.

        However it does appear that typically there are not laws against a person simply wanting to remain quietly anonymous, and situations where masks are considered illegal are rightly weighed against people’s rights to free speech and assembly (most places).

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