In the video game Metro 2033 and its subsequent sequels, players fight their way through a post-apocalyptic version of Russia using improvised weapons and tools cobbled together from the sort of bits and bobs the survivors of a nuclear war might be able to scavenge from the rubble. One of the most useful devices in the game is known as the “Universal Charger”: a hand-operated dynamo that the player must use periodically recharge their electrical devices.
Being a fan of the series, [Nikola Petrov] wanted to build his own version of the Metro 2033 charger; but rather than going for an exact screen replica, he decided to explore the mechanism itself and see if he could 3D print a functional device.
As demonstrated in the video after the break, his charger manages to produce enough energy to light an LED on each squeeze of the trigger. Though if we were packing our gear to go fight mutated beasties in alternate-future Moscow, we might look for something with a bit more kick.
Beyond the 3D printed parts, the charger uses a couple short pieces of 8 mm rod, a NEMA 17 stepper motor, and a one-way bearing that’s usually used for pull starting small gasolene engines.
Interestingly, [Nikola Petrov] is no stranger to 3D printed electrical generation. If you’re interested in getting some real power out of a NEMA 17 stepper, his fantastic printed wind turbine is a must-see.
Hand cranked dynamos seemed to be popular in USSR pre-apocalypse, though one could regard the revolution or subsequent Stalinism as pretty apocalyptic in effect, resulting in sparse commodity dry cell supplies, hence the popularity of these as flashlights. I guess you don’t come across that many in North America, where in the 70s they might have been a few imported as novelties for token trade. They seem to be somewhat available used, if you get past all the “rare, rare, rare” and “I know what I’ve got” and probably more plentiful in the former communist countries. Anyway, this one is near identical to one I picked up a whil back https://youtu.be/13gU_3dXfkI Though I don’t know if I’d call it tactical, they’d hear you coming a mile off with the whirrr whirrr whirrr noise you’d be making. Gives you a view of what you’d expect to find in one for modification. Seeing the AC waveform come out of it though, if you were modernising it as a flashlight you’d maybe want to stick 4 LEDs in a bridge rectifier configuration to make the most out of your output. Probably pretty easy to find some module or IC that will take a somewhat variable output and give you a nice clean and steady 5.1 V or so for USB charging.
Here in the west we’ve had similar devices as products, I have a Totes Weatherworks emergency cell charger kit with various adapters, I keep meaning to get round to splicing something a bit more modern than mini USB to one of the less useful adapters like micro USB at least.
I had a similar flashlight years ago, I was planning to convert it from incandescent to LED. But, my toddler found it…
Something that utilizes our walking motion.
humans are terribly inefficient at converting food into energy, even without factoring in the energy required to make food. Look at it this way: a hamburger costs the same as a gallon of gas. Which has more stored energy? Not even close. This is why we invented motors and engines to power stuff instead of using humans.
Right, use captured zombies.
You work out too much, N. Your average person isn’t caring around a gallon of fuel and a generator in a backpack or purse every day. Ostracus is probably looking for an emergency generator for a phone or flashlight, not a daily use charger.
Sure, but unlike gasoline, food literally grows on trees.
…which are grown, transported, and prepared for consumption using gasoline and other fossil fuels.
That’s the reason why a hamburger costs as much as a gallon of gasoline – the price reflects the necessary consumption of resources to make it available, and that’s ultimately going to be some form of energy. Mostly not sunshine.
My food grows in my garden, and is available for purchase at more places than gas stations.
But hang on. You, like a petrol engine are a heat engine, take fuel, burn it and exploit the difference between the hot and cold sides. Your entire system works at near equilibrium an 37C, a petrol engine works between about 90-100C and 350C, and yet your muscles work at about the same efficiency as a petrol engine.
Biology is amazing, much more flexible and reliable than technology in almost all circumstances. Often surprisingly efficient.
Ian
Sure if you want to live at 1850’s level life style. But I don’t see any geeks wanting to get by on sheer muscle power alone.
Try powering your refrigerator and A/C with your own muscles all day. Ohh that’s right you can’t. Or even powering your toaster while keeping the iights on in your apartment.
Actually, a good engine under an optimum load is twice as efficient as the human.
Hmmm. Did you really just compare the efficiency of different energy conversion systems using the cost of fuel as the only metric? … Unfortunately, it drove you to the wrong conclusion. Living organisms are BLINDINGLY EFFICIENT at converting food into energy. Can any plane in existence use as little energy as a bird to sustain flight? Not in your wildest dreams. And I can bike to work ten miles using less than the half the chemical energy content of a candy bar. (Yes, I did the math years ago… it is the depressing reality of weight-loss). I’m afraid no mechanical contrivance ever invented can match that efficiency. We only invented engines so we could use distilled dead organisms as fuel. They are for applications where we lack the peak power capacity and stamina engines provide. That, and we’re lazy!
Can any bird carry a human? No.
You need a fossil fuel powered aircraft to do it. A glider could but it’s limited to where and when it can be flown and it takes a fossil fuel tow plane to get it in the air.
Sure ride a bicycle to work, which is a nice office environment with central heat and air to keep you nice and comfy all year around. And when you need to carry a lot of heavy stuff, well you hire a pickup truck.
And you certainly don’t take your date on a bike unless it’s a Harley or Indian.
>” Living organisms are BLINDINGLY EFFICIENT at converting food into energy.”
Not really.
https://openoregon.pressbooks.pub/bodyphysics/chapter/human-metabolism/
[N], I disagree.
First, I will acknowledge facts you point out:
Fossil fuels have higher energy density than food.
The cost per unit energy is far lower in fuel than food.
However, neither of those have bearing on efficiency.
Assume a passenger car gets 32MPG and weighs 2,885lbs.
Also assume that you need to travel 47.06mi. You consume 1.47gal using 193MJ of energy.
That is ~1.42kj per pound per mile.
On a recent ride on my bike I traveled 47.06mi using 5,602KJ and weigh 150lbs.
That is ~0.79kj per pound per mile.
Therefore, from a pure efficiency standpoint, the human is almost twice as energy efficient as the car.
Now, with that information, let’s talk economics.
A human can literally survive on a diet of beans ($1/lb dry) and rice ($0.38/lb dry). Which supply energy at a quantity of Beans 6,453kj/lb, Rice 6,940kj/lb, meaning we use the energy equivalent to 0.42lbs of rice and beans.
Therefore, the 47.05 mile trip above would require $5.48 in fuel in a car (local gas station is $3.73/gallon) or around $0.29 worth of food.
(I realize my analysis is incomplete and makes a lot of assumptions on absorption/completeness of fuel burning, but am confident that those will still support the conclusions)
>”Therefore, from a pure efficiency standpoint, the human is almost twice as energy efficient as the car.”
You forgot to add in the increase in your base metabolic rate after exercise, for repairing the tissue damage. Depending on the level of exercise, that can double your energy consumption.
Also, food calories are measured by a bomb calorimeter where the food is incinerated and the temperature rise is calculated to derive the total chemical energy in the food. What your body extracts out of the food is actually less than that.
What your exercise program tells you is the approximate amount of work you’ve performed, adjusted upto calories by multiplying with some constant coefficient derived by the Stetson & Sleeve method – in other words pulled out of a hat. Most likely you need to eat more food than you’ve calculated to replace the energy anyhow.
>”A human can literally survive on a diet of beans ($1/lb dry) and rice ($0.38/lb dry).”
For a short while. After about a month, you become protein deficient and anemic, so your wounds and muscles no longer heal, and some time later your teeth will start to fall off due to lack of vitamin C.
You need more than 10% protein in your diet to remain healthy enough to be able to exercise – but if you stuff yourself with beans to gain it, the high lectin content of the beans acts as an anti-nutrient and stops the absorption of iron. You need to spend considerable energy to boil the beans in order to get rid of (most of) the lectin, or you have to ferment the beans to make tofu which does the same thing, but loses some of the energy contents. All in all, in terms of protein intake, you actually gain more protein in your diet by feeding the beans to chicken and then eating the chicken, with none of the adverse effects.
But have you ever tried to use gasoline to fuel your body?
Plundervolt…