Hackaday Links: August 18, 2019

Hackaday Links Column Banner

To the surprise of nobody with the slightest bit of technical intuition or just plain common sense, the world’s first solar roadway has proven to be a complete failure. The road, covering one lane and stretching all of 1,000 meters across the Normandy countryside, was installed in 2016 to great fanfare and with the goal of powering the streetlights in the town of Tourouvre. It didn’t even come close, producing less than half of its predicted power, due in part to the accumulation of leaves on the road every fall and the fact that Normandy only enjoys about 44 days of strong sunshine per year. Who could have foreseen such a thing? Dave Jones at EEVBlog has been all over the solar freakin’ roadways fiasco for years, and he’s predictably tickled pink by this announcement.

I’m not going to admit to being the kid in grade school who got bored in class and regularly filled pages of my notebook with all the binary numbers between 0 and wherever I ran out of room – or got caught. But this entirely mechanical binary number trainer really resonates with me nonetheless. @MattBlaze came up with the 3D-printed widget and showed it off at DEF CON 27. Each two-sided card has an arm that flops down and overlaps onto the more significant bit card to the left, which acts as a carry flag. It clearly needs a little tune-up, but the idea is great and something like this would be a fun way to teach kids about binary numbers. And save notebook paper.

Is that a robot in your running shorts or are you just sporting an assistive exosuit? In yet another example of how exoskeletons are becoming mainstream, researchers at Harvard have developed a soft “exoshort” to assist walkers and runners. These are not a hard exoskeleton in the traditional way; rather, these are basically running short with Bowden cable actuators added to them. Servos pull the cables when the thigh muscles contract, adding to their force and acting as an aid to the user whether walking or running. In tests the exoshorts resulted in a 9% decrease in the amount of effort needed to walk; that might not sound like much, but a soldier walking 9% further on the same number of input calories or carrying 9% more load could be a big deal.

In the “Running Afoul of the FCC” department, we found two stories of interest. The first involves Jimmy Kimmel’s misuse of the Emergency Alert System tones in an October 2018 skit. The stunt resulted in a $395,000 fine for ABC, as well as hefty fines for two other shows that managed to include the distinctive EAS tones in their broadcasts, showing that the FCC takes very seriously indeed the integrity of a system designed to warn people of their approaching doom.

The second story from the regulatory world is of a land mobile radio company in New Jersey slapped with a cease and desist order by the FCC for programming mobile radios to use the wrong frequency. The story (via r/amateurradio) came to light when someone reported interference from a car service’s mobile radios; subsequent investigation showed that someone had programmed the radios to transmit on 154.8025 MHz, which is 5 MHz below the service’s assigned frequency. It’s pretty clear that the tech who programmed the radio either fat-fingered it or misread a “9” as a “4”, and it’s likely that there was no criminal intent. The FCC probably realized this and didn’t levy a fine, but they did send a message loud and clear, not only to the radio vendor but to anyone looking to work frequencies they’re not licensed for.

28 thoughts on “Hackaday Links: August 18, 2019

  1. ” In tests the exoshorts resulted in a 9% decrease in the amount of effort needed to walk; that might not sound like much, but a soldier walking 9% further on the same number of input calories or carrying 9% more load could be a big deal.” OK, but how much does the weight of the exoshorts (!?) degrade performance?

  2. …programmed the radios to transmit on 154.8025 MHz, which is 5 MHz below the service’s assigned frequency. Man, that sure sounds like he just screwed up the repeater offset (except, yeah, I know, 5 MHz offset is usually in UHF). I wonder if Hanlon’s law applies: “Never attribute to malice that which is adequately explained by stupidity.”

    In any case, those FCC citation letters are always a fun read.

  3. That’s good news that the media outlets got at least a slap on the wrist for misusing warning tones. The same thing should go for radio adds that use emergency service sirens.

    1. Which methods do you think would be most efficient? I’m only coming up with pressure/hydraulic bladder with some sort of turbine or a piezoelectric effect design or linear generators or maybe some sort of rocker road maybe where the rotational axis motion drives? Would be strange having a range of motion significant in a road.

      I’ve thought the best idea would be take use of the power grid infrastructure and migrate to run the power lines down just under the road in the center lane and have some sort of directional shielding that could take the losses and put to use through an induction transfer. Would be a lot of Mu metal or metglass or pure iron I guess or whatever the best cost effective shielding to direct the field is. Seems could have some sort of active cover also that would open when a vehicle was over. Streetlights could just couple to the lines I’m thinking if efficient enough and not even need to be spliced in.

    2. Probably not. Piezo produces very, very low current. If you could extract energy it would probably come at the cost of fuel efficiency. Which by the time you convert the power a few times would probably be less efficient than going back to oil lamps to light the road.

    3. You could device something, but it would be incredibly inefficient. You are making a car generate motive power in a very inefficient way (about 30-35%), and then transferring it to the road via rubber tyres (also not very efficient).
      You will just shift the bill to the driver. The cars will consume more gasoline/diesel and pollute more. It’s not unlike driving up a slight gradient.
      It is MUCH more efficient to put that fuel in an actual generator and generate the lighting power with it. Or to just hook it up to the national grid ;)

      1. How about turning it upside down, hook the road to national grid and make it appear as always driving downhill? If it seems ridiculous, it just goes to show that amount of energy extracted from the vehicle, if we cannot spot any macroscopic change in how it feels to drive over such roads, is also ridiculously faint, so if it would solve some logistics issue, and if the energy would be used sparingly, perhaps the overall total losses would be worth our while.

    4. One of my housemates was working on something like that for his dissertation project for university. He described it as essentially free energy. I couldn’t work out a way to explain that it was more akin to making cars drive up hill constantly, he just didn’t get the physics.

    1. I think those loose cables are for sensors, not the things providing force. In order to provide any force to the legs they’d have to be very tight to the body, and also not shaped like wires.

    2. They do look sloppy, flapping in the breeze when not tensioned, but look at them carefully, especially the easily-visible rear ones. When un-tensioned (when the leg swings back) they are not retracted, and go very slack. When assist is required (when the leg is forward and beginning the footfall and swing back), the cable tightens quickly, pulling the leg backward.

      I imagine being slapped on the ass by a cable on every step will grow old quick for most people not in a certain scene, but it’s obvious how it works when you looks closely at it.

      I appears the tension is actually provided by the spool-like devices on the pack, operating through a Bowden-like arrangement.

  4. There isn’t a pairing offset in VHF like in UHF and competent 2 way shops know this so it couldn’t be attributed to trying to put the radios on a talk around channel. It is hard to know what may have happened, but just as a falling hammer always seeks glass, they wound up programming the radios 5 Khz from a public safety frequency. ( Cops, fire, ambulance, etc). Not good.

    1. I’m not aware of any offset convetion, fot land mobile radios regulated by the FCC, the evidence I have seen says there isn’t. My speculation for that is so, because that may give those who manage frequency assignments a better chance to manage the spectrum to serve the maximum number of users.

      1. Depending on the frequencies there are specific frequency pairings for mobile to mobile which is simplex and not offset, and specific frequency spacing for various purposes of 5 MHz for UHF, 45 MHz for 800 and 900 MHz for repeater/mobile duplex splits, various others for VHF marine , 3.65 GHz etc, but there are no specific standards for VHF landmobile radio.

  5. The EAS tones thing really is important. EAS is the last ditch alert when everything else, terrestrial fiber and cable, satellites, point to point common carrier microwave etc is dead and gone. EAS consists (believe it or not) of multiple redundant threads of distribution of audio tones and messages that are relayed and Daisy chained between terrestrial broadcast stations where each radio or TV station is monitoring another group of other stations and constantly decoding any of the tones received from an EAS alert. Each station in the monitored group is a member of a totally independent alert thread. As an example: a station in New Orleans may be assigned to monitor an AM station in Mississippi, an FM station in Arkansas and another AM station in Louisiana. Another station in New Orleans would be assigned totally different stations to monitor. There would be maybe 10 other radio stations in other towns that might be assigned to monitor the first New Orleans station as one of its assigned stations and 2 other stations in other locations. All of this decoding and retransmission is totally automated with no human interaction.

    SO.. if a movie or TV show played the EAS tone coding sequence which indicated some large disaster or nuclear take cover and this was properly decoded by a station in the critical path it could activate a national false alarm, alerting cops fire municipalities etc. It is almost a sure thing that a nationwide activation would cost millions before it is shut down.
    At the level of Kimmel, the networks have the very best white stockinged DC law firms who constantly provide programming compliance training for the networks and all affiliates. They know better and I know their chief engineers know better.
    I’ve got absolutely no sympathy for the fine amount. Probably should be more.

    1. I remember watching “The Day After Tomorrow” way back in the 1980s, the TV movie about a full-scale nuclear exchange and the aftermath. Just before the missiles flew, kids had their after school cartoons interrupted by That Sound. It had never occurred to me until I watched that scene that I could someday hear that tone for real, not just in a test, and that if I did, it would probably be one of the last things I ever heard.

  6. When it comes to solar roadways, I always thought the positional for pavement to collect heat is being over look, particularly in cities. During Winter they could supply supplemental heat to building lining the street. or heating the transfer fluid from another heat source for ice and snow removal.

    Of course the FCC should not miss any chance, to adise about the regualtion

      1. Having a large heat build up when the energy isn’t used isn’t really the same as there being a lot of energy. Imagine a battery with a high open circuit voltage, but with a very low current limit. Or a very tall tube of water, but very thin.

  7. In other news – being sedentary is rising as one of the major preventable causes of death.
    How soon before they do something like that exosuit to increase the effort required in
    walking/running, so you can exercise faster.

  8. Note that in the Netherlands, there is a “solar highway” project, which does not use the roads, but sound screens around the highway (which are quite common here)
    Much better idea, as there is no stress on them other then the wind.

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.