4 ms·

Yea, totally, but this all assumes you can get ammo too. That's way harder than making a gun. Maybe a 3D printed taser would actually be more accessible?

duncan_bayne 11y ago
Given the amount of energy in a typical smartphone battery, I've wondered about making some sort of replacement back, loaded with supercapacitors and a couple of contacts, so the entire phone could double as a stun-gun ...
- jacquesm 11y ago
  With a little bit of creative re-wiring it might even double as a grenade.
  - duncan_bayne 11y ago
    Hah! My wife owns one of the Samsung S3s with the 'swelling battery' problem; those things are almost grenades out of the box :)
    - jacquesm 11y ago
      People really underestimate the potency of a cell phone battery. It always makes me laugh how the airline security check will confiscate bottles with baby milk and water but lets through a couple of hundred high energy batteries without a problem (laptops, cellphones, tablets). Now what could a creative terrorist do with a few phone batteries and some wire. Might even be enough to burn through the cockpit door of an airliner.
      - duncan_bayne 11y ago
        I don't know about that, but you could probably make some sort of thermite-phone, with a flammable body ignited by the energy in the battery. If done carefully, you could possibly have the thing behave like a fully functional phone until ignited. Doubt it'd bring down an airliner but it'd cause no end of panic and chaos onboard.
        jacquesm 11y ago
        Being somewhat practical oriented I've half a mind to try to see what kind of a 'bang' one could get out of a cellphone or laptop battery but I have two worries: the first that it will succeed, the second that it will succeed a bit too well resulting in people no longer being allowed to bring laptops and cellphones on board of airliners and I have enough enemies as it is ;) It's strange that nobody tried this to date (or at least, I can't find any hard evidence about people trying to blow stuff up with cell phone or laptop batteries).
        duncan_bayne 11y ago
        A fully charged 1000mAH 3.7V battery contains ~ 13kJ of energy. One gram of TNT gives you ~4kJ. So at best - assuming you had some way of efficiently exploding a smartphone battery - you'd get a couple grams of TNT yield. I suspect shocking, burning or smoking would be a better route to weaponising a smartphone. Edited: for comparison, the muzzle energy for a .50BMG round is ~15Kj. Bearing in mind you get ~4kJ from a gram of TNT, this explains why being shot hurts so much :)
        jacquesm 11y ago
        Laptop batteries do 200-400 Kj, that's 50 to 100 grammes of TNT. I'm not sure how much damage one could do with 100 grammes of TNT but surely you could find more than just one laptop battery to work with. Working grenades use anywhere from 50 grammes or more of TNT filler. The damage would very much depend on how fast you can liberate that energy and how well you could focus the blast.
      - jsmeaton 11y ago
        At least a few of you are currently being added to the no fly list. Also, relevant https://xkcd.com/651/ https://xkcd.com/651/
        jacquesm 11y ago
        > At least a few of you are currently being added to the no fly list. As long as they don't add me to the 'no drive list' I'm fine with that. > Also, relevant https://xkcd.com/651/ https://xkcd.com/651/ That's pretty much word-for-word, funny!
        duncan_bayne 11y ago
        I should have been added to that after I broke a light aircraft learning how to land them ;)
      - TeMPOraL 11y ago
        Two things: 1. Don't give them ideas. I have a bunch of LiPols I want to get back home with next week. 2. I've heard and repeated that fact, but come to think of it it still makes me wonder - do hand grenades really have so little energy?
        jacquesm 11y ago
        The trick of a grenade is not the amount of energy that it packs, it is the duration over which it releases that energy. Compare with a balloon. You blow it up with a little bit over atmospheric pressure over a large amount of time. But when you puncture the balloon all the energy is released over a very short amount of time. This is also why relatively harmless firecrackers become a lot more violent when you constrain them using duct tape or some fracturable container.
        duncan_bayne 11y ago
        Re. 2, yes, but much https://en.wikipedia.org/wiki/Explosive_material#Brisance https://en.wikipedia.org/wiki/Explosive_material#Brisance
        TeMPOraL 11y ago
        Thanks, didn't know that word before!

duncan_bayne 11y ago

Given the amount of energy in a typical smartphone battery, I've wondered about making some sort of replacement back, loaded with supercapacitors and a couple of contacts, so the entire phone could double as a stun-gun ...

jacquesm 11y ago
With a little bit of creative re-wiring it might even double as a grenade.
- duncan_bayne 11y ago
  Hah! My wife owns one of the Samsung S3s with the 'swelling battery' problem; those things are almost grenades out of the box :)
  - jacquesm 11y ago
    People really underestimate the potency of a cell phone battery. It always makes me laugh how the airline security check will confiscate bottles with baby milk and water but lets through a couple of hundred high energy batteries without a problem (laptops, cellphones, tablets). Now what could a creative terrorist do with a few phone batteries and some wire. Might even be enough to burn through the cockpit door of an airliner.
    - duncan_bayne 11y ago
      I don't know about that, but you could probably make some sort of thermite-phone, with a flammable body ignited by the energy in the battery. If done carefully, you could possibly have the thing behave like a fully functional phone until ignited. Doubt it'd bring down an airliner but it'd cause no end of panic and chaos onboard.
      - jacquesm 11y ago
        Being somewhat practical oriented I've half a mind to try to see what kind of a 'bang' one could get out of a cellphone or laptop battery but I have two worries: the first that it will succeed, the second that it will succeed a bit too well resulting in people no longer being allowed to bring laptops and cellphones on board of airliners and I have enough enemies as it is ;) It's strange that nobody tried this to date (or at least, I can't find any hard evidence about people trying to blow stuff up with cell phone or laptop batteries).
        duncan_bayne 11y ago
        A fully charged 1000mAH 3.7V battery contains ~ 13kJ of energy. One gram of TNT gives you ~4kJ. So at best - assuming you had some way of efficiently exploding a smartphone battery - you'd get a couple grams of TNT yield. I suspect shocking, burning or smoking would be a better route to weaponising a smartphone. Edited: for comparison, the muzzle energy for a .50BMG round is ~15Kj. Bearing in mind you get ~4kJ from a gram of TNT, this explains why being shot hurts so much :)
        jacquesm 11y ago
        Laptop batteries do 200-400 Kj, that's 50 to 100 grammes of TNT. I'm not sure how much damage one could do with 100 grammes of TNT but surely you could find more than just one laptop battery to work with. Working grenades use anywhere from 50 grammes or more of TNT filler. The damage would very much depend on how fast you can liberate that energy and how well you could focus the blast.
    - jsmeaton 11y ago
      At least a few of you are currently being added to the no fly list. Also, relevant https://xkcd.com/651/ https://xkcd.com/651/
      - jacquesm 11y ago
        > At least a few of you are currently being added to the no fly list. As long as they don't add me to the 'no drive list' I'm fine with that. > Also, relevant https://xkcd.com/651/ https://xkcd.com/651/ That's pretty much word-for-word, funny!
      - duncan_bayne 11y ago
        I should have been added to that after I broke a light aircraft learning how to land them ;)
    - TeMPOraL 11y ago
      Two things: 1. Don't give them ideas. I have a bunch of LiPols I want to get back home with next week. 2. I've heard and repeated that fact, but come to think of it it still makes me wonder - do hand grenades really have so little energy?
      - jacquesm 11y ago
        The trick of a grenade is not the amount of energy that it packs, it is the duration over which it releases that energy. Compare with a balloon. You blow it up with a little bit over atmospheric pressure over a large amount of time. But when you puncture the balloon all the energy is released over a very short amount of time. This is also why relatively harmless firecrackers become a lot more violent when you constrain them using duct tape or some fracturable container.
      - duncan_bayne 11y ago
        Re. 2, yes, but much https://en.wikipedia.org/wiki/Explosive_material#Brisance https://en.wikipedia.org/wiki/Explosive_material#Brisance
        TeMPOraL 11y ago
        Thanks, didn't know that word before!