Hackaday Links: November 6th, 2011

Build details for Raspberry Pi prototype

With the launch of Raspberry Pi approaching the development team released the details about the prototypes from about five years ago. The board was originally based on an ATmega644 and built on some perfboard.

‘Zero Energy Device’ challenge

We call BS on the title of this one, but the goal of finding devices that don’t use disposable energy sources is a good thing in our book. For instance, can we get more stuff that uses long-life capacitors instead of batteries?

Command adhesive for mounting bulletin boards, etc.

This seems like a no-brainer, but we’ve been using nails to mount bulletin boards and white boards for year. The problem is, when you stick a push-pin in one side, the other side pops off of the nail. [Zhanx] is using adhesive from 3M Command Hooks to keep his stuck to the wall.

Servo-driven gripping hand

[Navic] has been hard at work on this robot hand. There’s few details but he shows it can grip objects under one pound and he’s been taking amperage measurement during testing.

Emergency cellphone charging

It might not have been an emergency this time, but [Chris] did figure out a way to charge his cellphone after the snow storm in New England knocked out his power. He connected to lantern batteries to a 7805 regulator, then patched that into a USB hub to get his phone connected. Not bad in a pinch!

Comments

  1. Wouter says:

    I would love to see remote controls with the IC solar cells and a capacitor. They don’t use a lot of energy per day, so it should be possible to have ‘never ending’ zap devices this way.

  2. A Canuck says:

    The cell phone charger is a wonderful true hack.

    The use of the command hooks is smart, but I think 3m also makes a product that does exactly that.

  3. wb says:

    You put pushpins in whiteboards?

  4. Joe Engineer says:

    I love the irony of using a CdS (Cadmium Sulfide based light sensor) in a “green” project. Cadmium as we all know is a substance that is restricted in various parts of the world due to its effects on environment and health. The idea of using such part is totally not “green” at all.

    http://en.wikipedia.org/wiki/Cadmium#Regulations

  5. cgimark says:

    Another trick for charging usb devices without power. You need 6 volts battery power from whatever source, glass of water + salt, voltmeter. Connect the ground to the battery, the positive wire put in the salt water . The device to be powered connects to another wire and is dropped in the water at the farthest point from the battery positive. Connect device and measure voltage across the devices power input. Slowly move the wire in the salt water closer to each other. When close enough tape in place.

    The salt waters variable conductivity works to regulate the current.

  6. cgimark says:

    When I said The device to be powered connects to another wire and is dropped in water, I meant the other wire is dropped in the water, not the device :)

  7. Steve-O-Rama says:

    Wouldn’t it be nice if our cell phones, and wireless devices in general, could stand a wider range of input voltage? I mean sure, there would be compromises, but between the choice of no phone, and slightly-heftier or slower-charging phone, I think I’d rather have the latter.

    Good work on all of these, btw. I really like the “no disposable energy sources” one. The supercap and Li-Ion/LiPo/LiFe battery and capacitor technology just keeps getting better (albeit sometimes more complicated) all the time. I can remember when holding a device capable of multiple farads in the palm of your hand was only possible in “the future”. :)

    • Mike Szczys says:

      I disagree. Having a wider range of input voltages would increase the cost of every phone. What I’d like to see is a small set of standardized voltage inputs and connectors for mobile devices.

      This way you could have on charge that has a wide range of input voltages, but could work for all of your mobile devices.

    • cutandpaste says:

      Some devices do.

      For instance, my first-gen iPod Touch (and previous Apple iPod-ish gear that I’ve actually looked at) supports anything from 5V to 30V, either DC or PWM. Or at least, that’s that the ideograms on the back indicate.

      It’s a shame about the silly iPod Dock connector. But at least it’s flexible enough with voltage that one can hack together a charger given a few batteries of almost any type, a connector, and (optionally) maybe a sharp knife and a rubber band or two…

      More devices should be built like this, especially since it’s extremely likely that the first thing any input voltage will find on its path through the device is a switching DC-DC converter.

  8. bob says:

    Stupid idea to use ultra Farard capacitors, the leakage figures are horrendous

  9. phisrow says:

    Does anybody know were those curious solar-cells-in-DIP-wit-a-lot-of-NC-pins parts show up in the wild?

    I’m assuming that there must been(or have been) some reasonable demand for enough of them to have been packaged like that; but I’ve never seen one before, only the slightly larger leaded ones you seen in cheapo calculators, the smallish ones in plastic or epoxy cases they sell for hobby applications, or the much larger panels for battery charging or power generation.

    Has anybody ever opened something up that used similar parts?

  10. Adrian Hum says:

    What I don’t get is why we went away from standard USB chargers and connectors on phones?

    Nokia seems to have gone back to the 2 conductor center pin arrangement iPhone and iPad to a well we won’t talk about that connector. RIM to micro USB. And the list goes on.

    • cutandpaste says:

      Dunno where you’re from, but around here everything recently-made uses Micro USB except for Apple products (for which there is an official adapter available).

      There was an EU directive a couple of years back stipulating this transition to Micro USB. There seems to be more information about that here.

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