Yann Vernier’s Blog


Hand powered electrical generators

Filed under: Gadgets — yannv @ 00:46

When I was younger, the dynamo flashlight was a fairly common product. Usually it would consist of an electromagnetic generator, a lightbulb, a flywheel for energy storage and a lever with some sort of clutching mechanism. One would squeeze the lever into the body of the device to add power, then allow it to extend again. This could easily be operated with one hand, even wearing mittens, as one simply closes and opens the gripping hand.

Nowadays, I’d be vaguely annoyed at any generator that didn’t provide an outlet. I’ve been on the lookout for a handheld generator, and while lots are available, most are simply hand cranked. Those require much finer manipulations, and tend to end up with obvious inefficiency as our arms just aren’t unlimited rotary joints. Besides that, frequently the device itself it downright fragile, which doesn’t mesh well with the concept of applying force to get it to work at all. I’d like something different.

Squeeze dynamo

I finally found one; the Revolve xeMicro. It looks like a decent enough product, but I’d prefer a european plug if the device is to have AC input. I’ll keep looking a bit.


A nice little article on hackaday pointed out this possibility. A commenter linked to a commercial offering of the same thing called Manual Power. This has a configuration which appeals to me; there’s no crank, in fact no externally moving parts, and it doubles as a decent training device. I’ve had the opportunity to test one without the power harvesting feature. One for the wishlist, or perhaps when I have money to spare.


I heard of the Potenco pull-cord generator through the One Laptop Per Child project. It has a rather impressive power output, at the cost of requiring two attachment points; though one could allow one to be static, say, tied to the backpack or held underfoot. Unfortunately, it isn’t available for purchase – and I’m not inspired with much hope when the FAQ hopes for this to change mid-2009, over a year ago.

Another company, supposedly called “Easy Energy” (like dozens of others), has shown both pullcord and pedal generators under the brand Yogen. Unforunately, they recently (2011-08-11) decided to drop off the net, so that doesn’t look very promising, either.

Linear motion harvesters

Kinetic energy harvesters like nPower PEG rely on some internal moving weight, typically a magnet sliding through a coil. I’ve seen flashlights of such design, and while most of them are rather inefficient, it could have the advantage of being passively usable. The suggested example is attaching it to a backpack, thus converting a little energy from each step. Again, however, this particular model doesn’t seem available to purchase.

As usual, I would dearly love suggestions of further options!


More parallel computing chips

Filed under: Electronics — yannv @ 17:06

Somewhat over a year ago I jotted down some notes on parallel microcontrollers. I hadn’t heard or done much since, but a few things have happened. I ended the note with a plea for more options, and today it was finally – albeit indirectly – answered. Slashdot picked up some PR from Intel regarding higly multi-core processors, and a comment regarding other brands mentioned two I had not yet heard of.

GreenArrays has started offering some of their larger chips for sale. They’re another product I suspect will be relegated to niche status and forgotten, which is really a pity as they have some very good ideas. The problems aren’t very complex, and not necessarily crippling. First, the whole design is based on the creator’s favourite language, Forth. It is a 1970’s language, and hasn’t changed much since. As such, the grand interactive development system is.. well.. like an 80s microcomputer. It simply doesn’t scale well, and that’s a problem when scaling is what it’s all about – they offer 144-core chips! The other drawback is the lack of communications routing, as all those cores must programmatically shuffle data between them (and yes, the entire layout has to be done manually for now). Finally, don’t expect a hobbyist foothold when only large BGA models are available, nor much of an industrial one while you’re the only source and porting costs would be immense. Where the design shines is in power efficiency, and it’s fairly impressive when it comes to speed and code density, but it just doesn’t seem enough.

Picochip multi-core DSPs fall in the hybrid chip category. They feature a reconfigurable section, but instead of the bit-level FPGA design they have a bunch of DSPs, while ARM cores handle the general purpose computing.

The Icera chips, on the other hand, I found no actual details about. It reminds me of Zii – there’s some DSP going on, but they won’t tell what.

The Zii Plaszma is actually being sold, with plenty of marketspeak claiming it’s revolutionary, but they seem more focused on making up analogies and buzzwords rather than admitting anything about the architecture or specifications. In fact, they’re so busy making these up that they’re outright lying about what other things do. Their marketing has convinced me not to trust them.

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