Hackaday Links: August 16, 2015

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[Matt] created an animated gif of New Horizon’s Pluto flyby. The source images were taken from the the raw LORRI images, modified so the background star field could be seen, and assembled with OpenCV. Because Pluto and Charon orbit each other around a point above Pluto’s surface, simply putting Pluto in the center of each frame wouldn’t work. It’s the best visual explanation of this weird arrangement yet, all brought to you by the magic of OpenCV and Python.

On the subject of Kickstarter creators that don’t understand the conservation of energy, I present this.

We don’t know exactly what’s going on with this one, but here’s a swimming pool covered with RGB LEDs. It’s controlled by two Rainbowduinos, and looks like the coolest disco floor you’ve ever seen.

[Frank]’s 2011 Hundai Santa Fe wasn’t cool enough, so he added an F16 flight stick to his shift knob. The choice of joystick is paramount here: Saitek joysticks look too techy, Logitech ones are too expensive, and the Warthog H.O.T.A.S costs $400. Joysticks are extremely niche peripherals these days, it seems. He ended up strapping an old F16 joystick from the 90s on his shift knob, and it looks close enough to the real thing.

Two bodgers are stuffing the engine from a Toyota Celica into a 1980 Mini, and they’re trying to make it look stock. We’ve seen their project before, and now there’s a new episode. In this episode: the pedal box, the steering wheel, and figuring out how to make the car drive straight.

42 thoughts on “Hackaday Links: August 16, 2015

  1. Gonna make myself look stupd here but why would the wind turbine hingy not save energy? I know there is no free energy, no perpetual motion or anything like that. Is it because the AC would have to push the air out harder because of the resistance from the turbine? Or am I missing something?

    1. I must be stupid too, because I don’t think you are missing something. The turbine is far enough above the AC condenser unit so as not to reduce its airflow, so it has no negative consequences. He isn’t adding heat to the condenser, so it doesn’t reduce it’s efficiency. It’s just power that would be wasted anyway, so you may as well grab it.
      An alternate setup would use the waste heat from the condenser to boil a fluid, like in a organic Rankine cycle setup, to spin a turbine / generator setup. But that would be more complicated and not as efficient.

      1. Well, he’s confusing volts & energy, so that’s an immediate fail.

        His video shows some sort of electronic load on the output (a plus as he’s not measuring open circuit voltage) but doesn’t give any numbers around what the load is actually doing. Fail number two.

        As always, when the backyard genius inventor trots out his new & shiny, what’s the current status? He claims 350w, here’s a commercial 350w unit: http://www.offgridbatteries.com.au/superwind-350w-24v/


        There are a bunch of wind energy calculators online, his claims are a little fanciful.

        Will it work?

        Sure. Reclaiming low-level waste energy is nothing new (eg Stirling engines), but it’s rarely worthwhile from a return on investment point of view.

          1. The only measurements he gives is when he cuts bits off his blades, the output voltage goes up by 0.8V to 2V.

            Uh huh.

            What he’s done is find a 350W generator that states “if you spin this at X RPM it will produce 350W”. So he’s plonked his fan onto the AC exhaust, and found it spun at X/3 RPM. No worries, toss in some 3:1 gearing, job done.

            Then he’s noticed that the faster it goes, the more volts he gets, and as we all know volts = energy.

            So the lighter he makes his blades, the more volts and thus more energy. Awesome.

            He really should read up on torque one day.

    2. I guess the guy would need to measure the power draw and temperatures of the condenser unit with and without his turbine setup to verify the device does not increase the power draw or temperature of the condenser coil.

      1. Yeah I am pretty sure that in order for the turbine to move it must put move pressure on the AC fan, Just imagine there was a “hypothetical chain” connecting the two in order to move the turbine mass the AC fan has to work harder to have the same level of efficiency. It was because they were not touching that it confused me for a little. The air is not waste it is being moved not wasted.

        1. Sure, but the air that exits the top of the condenser unit has already passed through the condenser coil, picked up some heat and is being exhausted out the top by the fan. So, if, by some miracle, the addition of his turbine did not load the condenser fan, then one could argue the power produced by his turbine would have been wasted anyway.

          1. Yep, if he enclosed it he’ll get more power out.


            At that point that whole “no free lunch” starts to come into play as that’s the point where he really does start putting a larger load onto the AC fan, making it draw more power.

            One thing to remember is the AC fan only uses a small fraction of the total AC power, so the extra load may be lost in the noise. He claimed adding his device made no difference, that’s why.

            It will kinda sort work, but in order to get 350W out the AC fan itself would need to something like a 2,000W unit once you take into account all of the losses, eg there’s at least 5% lost in that 3:1 belt drive.

            It’s just stupid. It’s like having a solar power lamp, where the lamp shines on the panel to recharge itself. That’ll work just fine, for a very tiny amount of extra run time.

            The best idea is as [RÖB] said, put in on your neighbours AC unit.

    3. It will add resistance to the air flow, so, for the same condenser fan, there will be either less heat rejected at the condenser coil (lower performance), the same heat rejected at the condenser coil, but at a higher temperature (lower efficiency) or some combination of the two.

      Also, those fans on a residential condenser unit are nowhere near big enough to be scavenging 350W from the flow with a turbine like that- that’s like 1/2 (or more) of the energy that the fan is consuming in the first place.

      But, as others have said, it might pay for itself if you put it on your neighbor’s condenser unit.

    1. You and I saw Episode 10 the day it went up, of course, but there are still people out there who haven’t yet encountered Project Binky and all its Cardboard-Aided Design, expert-angle-grinder-wielding goodness. I salute Hackaday’s public service.

  2. seems like the air conditioner generator should work, condensers are not perfect heat gatherers to begin with so there might not be that much lost as far as loss of cfm through the radiator. The biggest complaint I have is the legality of the system with the plugging in a microinverter to the wall like he is suggesting. That is illegal as far as I know, at least in the u.s.. So I don’t think you are ever going to get a ul listing on this device.

      1. Why store it for later use if your grid power is reliable? Batteries cost money, charge controllers cost money, maintenance costs go up. 90% of all pv projects I’ve installed in the last 5 years have been direct grid tie systems with no batteries in the system.

    1. This is nothing new. Stick gen on fan. Measure Voltage and Current and the calculate power. FAIL number 1) because you are measuring ‘power’ that is coming from energy store as momentum in the generator and the actual constant power output would be much lower. So when you base all the other calculation on this incorrect calculation you end up with the proverbial ‘over unity’ impossibility.

      The only energy that is is possible to retrieve from this ‘waste’ without drawing more energy from the original system is the kinetic energy from the thermal convection of the heated air.

      The whole problem comes from the fact that [momentum = mass * velocity] and [kinetic energy = (mass * velocity^2)/2] Just like the newtons cradle, you must balance both in any equation.

        1. Exactly this, it’s simply a recapture of waste heat I don’t see any over unity claims or free energy claims. I think it’s a dumb idea anyway as it will not be efficient or worthwhile nor can you dump this back into your house legally without risk of fire.

          1. The over unity claim is here – “It is capable of putting 350 watts of power back into your home anytime your air conditioner is running”

            Why stop there? You could get a 10,000 watt electric motor and connect it to a 10,000 watt generator and then put a massive 10,000 watts back into your home! Wouldn’t that be much better?

            *Face palm*

          2. How is that a claim of “over-unity”? It is just a claim of capturing 350 Watts that would have been dumped into the atmosphere. He make no claim of generating power that magically appeared. He makes no claim of that power being enough to run the AC unit.
            How much thermal energy is being dumped into the atmosphere from that condenser unit? What is the air temperature before and after the condenser coil with and without the turbine unit, what is the electrical power draw with and without the turbine unit, and what is the mass flow of air with and without the turbine unit? Those are the things we need to know to make a judgement of usefulness.

          3. @Mark

            You have a box. There some wires going into the box and some going away to a load. You measure the power to the load and it is 1000 Watts, you measure the power going into the box and it is 1000 Watts. No bigy. You come back to the box another day and now there is a second load. You measure the first load and it is still 1000 Watts, you measure the second load and it’s 250 Watts. Now what are you going to see when you measure the power going into the box? Will it still be 1000 Watts?

            Then you mentioned the heat coming out.

            You have an electric probe. It is energised to 16 gazillion volts. You have a second electric probe, it is also 16 gazillion volts. You tough them together. Do you get a massive explosion because they’re 16 gazillion volts? No, not at all because there at the same voltage. So you need a difference in voltage to transfer energy. The same applies to heat: you need a difference.

            Here’s a way to convert the heat to energy that’s easy since you already have a cool room. Remove one window of the air conditioned room and replace it with a peltier, now point the heated exhaust at the petlier from outside. You get 5000 Watts from the peltier. Of course the room heats up a little in the process but no bigie just increase the air conditioning power by 5000 Watts and it will come back to what it was before you put the peltier in.

            Electronics is an amazing thing. It promotes people to understand and rationalise things that can never be seen. If you get confused by all these changes in the state of energy just think of it the same way you would with electronics. ie what’s going into the box and what’s coming out. Just ignore the energy state transitions because energy is always conserved no matter how may transitions it goes through.

          4. Despite what the clueless Had-It’s-Day editor wrote, this doesn’t violate the laws of physics.

            You can extract energy from the air unit’s exhaust, that’s the basis of this persons claim.

            The real debate is how much, and is that enough to make it worthwhile. (Hint, no it’s not)

            As an aside, I’ve no idea of what [RÖB] is on about. What heat? As [alfiesauce] say it’s a windmill; air comes out, it spins. Who cares how hot it is?

            And it’s not a closed system, so eh?

          5. @Rob
            It’s a 3 ton Lennox system. It draws ~4.5KW, if he can re-claim 300 Watts or more of that, there is no reason why not too. It breaks no laws, it is just physics. It’s not some nutjob “over-unity” claim.

          6. @Mark

            I suggest you go and google what a 350 watt fan looks like.

            I’ll put it this way. If you bolt the second fan to the AC unit. Seal up every gap so that every molecule of air moved by the AC fan *HAS* to pass by the second fan, and strip out everything from the AC that can get in the way of air flow like the radiator and compressor, then, and only then, you would get the maximum output conversion and that would likely be about 50 Watts or less by the looks of the add on fan.

            By the way the fan in the aircon is probably about 150 Watts.

            Someone mentioned the brand model so I will go google.

            You know, just to prove that energy conservation is a thing, lol like a law of physics much?

          7. @Rob
            No-one except the author of the video is claiming 350 Watts. Proper measurements would need to be made of power output.
            The increase in air volume due to the temperature difference between the intake air and exhaust air would also need to be calculated to determine the power available properly.
            The condenser fan on that unit draws 750 Watts (it is a 1 horsepower single phase motor with starter capacitor for rotor field). So even if it were coupled directly to a generator, the best one could hope for is about 650 watts of power.
            The best way to measure the usefulness of such a device is to measure the temperature increase in the condenser coil with the turbine device installed. This would allow you to determine the effect on the efficiency of the air conditioning system. An increase in coil temperature would cause the system to run longer to cool the building to the thermostat set temperature, and would use more electricity while doing so, and would negate any yield in power from the turbine device.

  3. Years ago my brother-in-law bought an original Mini-Cooper and rally raced it. He paid about $3K for it. Then the new Mini came out and the value of his old one increased by ten fold. He didn’t want to risk damaging it on the track after that…

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