This post originally appeared on digitalcommons and is republished here with Steve Cisler's permission.
Colin Bulthaup, Potenco
On July 3, 2007, The Institute For The Future hosted a talk by Colin Bulthaup, CEO of Potenco, a spinoff of Squid Labs, based in Alameda, California. Colin characterized SL as a Do Tank, not a think tank.
Fourteen months ago they had been working on smart rope, a rope that knows when it is about to break, but with a grant from the OLPC team they developed a pull-cord generator (PCG) that can be used to charge mp3 players, mobile phones, LED lights, portable batteries, GPS devices, and the XO laptop.
Their base line human is an eight year old pulling on the yo-yo device. They even tested the amount of CO2 produced as a kid uses it, as well as calories expended (very few). One minute of pulling generates enough energy for 20 minutes of talk time on a mobile phone and four hours play time on an iPod Shuffle.
Colin explained that they had done research on the best kind of string, using some new synthetic material, and as backup, there are two extra sets coiled inside the housing of the device. They have designed it so that it can be hacked. For instance, by removing the cover (top picture) it could be attached to a bicycle hub and generate more than 20 watts of power.
Here is a short YouTube video where Colin demonstrate the PCG:
He is interested in how the availability of decentralized electricity will change village life and spur small scale entrepreneurs who will provide charging for others. I suggested that patterns of exploitation in a culture will be repeated with the advent of a new technology, so you might see kids and women assigned/forced to do the charging, but the technology makes much more sense that hauling a car battery around to charge phones in rural areas.
It was relatively easy to pull repeatedly, and the stronger the person the greater the resistance and higher wattage generated. Colin had a hexagonal battery consisting of an array of LEDs, 2 USB ports (the standard for charging these days), and a DC input. This was a proof of concept, and the commercial battery will look different. Colin discussed the problems of using kerosene for lighting. Besides being very inefficient, it was dangerous and contributed to respiratory disease, and was quite expensive. He sees this advanced lighting as an important replacement for kerosene.
Frustrated adult OLPC user
He also brought an early model of the XO laptop. Many of these will be in rural areas with little electricity infrastructure, so each ministry of education placing orders will have to determine how many PCGs they will need for those users who have no other source of electricity.
I asked what the cost will be, and while it was not finalized he said it would add about 10% to the cost of the XO. At this time that would be about $17.
There are plans to sell it commercially in retail, and they have a number of ideas about the next phase, especially in the health sector. One African has developed a low cost defibrillator which could be charge in ten seconds of pulling! Another application is small-scale refrigeration for drugs in hot climates.
He brought an earlier version of the XO and asked who wanted to try it. One person said people had a hard time figuring out how to open the XO, and indeed the researcher who volunteered took 53 seconds to figure out how the screen opened up!
This post originally appeared on digitalcommons and is republished here with Steve Cisler's permission.
"For instance, by removing the cover (top picture) it could be attached to a bicycle hub and generate more than 20 watts of power."
Seems like every time there is an article about the technology in the XO, there is some new use or benefit.
Those who think oplc is useless should remember they are shooting at a moving target.
Argh- we went thru' the ergonomics of human powered battery charging some postings back! Human hands are much more likely to be needed for keyboards & mice,or for holding papers/lights/food drink/babies/animals/cooking utensils etc. In contrast our MUCH MORE POWERFUL legs usually hang idle indoors,& they've stamina that's naturally far greater as well. Never mind a few Watts from a hand Portenco, as 50 Watts from a pedal gene is a easy-even for a child! Leg power is the way to go !! See the popular New Zealand "Smartdrive" => http://www.manuka.orcon.net.nz/smart.jpg
IMHO it's a waste of R&D effort to be focusing on such puny hand driven unit for OLPC, especially since Negreponte himself demonstarted they were not able to power a OLPC alone- implying their output only ~ 2 Watts. NUMEROUS similar wind up LED torches & cell phone chargers already now abound at ~US$10 of course giving similar output AND greater verstaility. See => http://www.taps1clubstore.com/files/CPB00000/187.jpg
Potenco can be attached to a bicycle to generate the 50 Watts. But not everyone has a bicycle. Though everyone has a wall or a tree on which you can fix it and use your weight to generate the 20 Watts or more.
The Potenco may well hand generate brief 20W peaks,but I'd like to see data showing it's sustained output. Both the energy Physics & my experiences say only a few Watts on average will be achievable by hand...
"Colin explained that they had done research on the best kind of string, using some new synthetic material, and as backup, there are two extra sets coiled inside the housing of the device."
String:
*******
Often concern was expressed that the pull string might be a weak part of the Potenco yo-yo. Now we know that modern high strength fiber is used and two spare strings are integrated in the yo-yo.
Connecting cable:
*****************
However, after watching the video of the yo-yo in use I suspect that the electric cable from the yo-yo to the XO is also at risk of fatigue from bending and yanking around.
Interfacing Connectors:
***********************
The yo-yo has a single connector at the end of the connecting cable that plugs in either the XO or the hexagonal external battery. This external battery has USB sockets and according to the video a 12V socket. Why not also include USB and 12V sockets in the yo-yo for more versatile usage? Instead of a 12V socket it might be even more versatile to have two isolated 12V clamps for taking raw wire ends.
EXTRA: Check WW2 era hand powered rescue dinghy transmitters like the "Gibson Girl" => http://wftw.nl/gibsongirl/gibsongirl.html These SOS sets typically managed a max of ~10W from their gene,& that was with downed aircrew cranking as if their lives depended on it. Well- it often did!
Hello Stan,
thanks for the interesting link about the rescue transmitters. I guess that even the latest technology of that era did not include super strong rare-earth permanent magnets for the generator or semiconductors for nearly lossless voltage stabilization and signal amplification.
Your link does not say what the generator power output was. The only given information concerning power is about the german precursor model NS2 that yielded 8W radio output. Taking the inefficiency of the thechnology of that era into account the required innput power at the crank might have been much higher than 10 W. Moreover, the emergency radio without a battery included was probably supposed to be continously cranked for many hours per day in order to be located by searching rescue aircraft.
Therefore I don't think your example disqualifies the child operation of the yo-yo for 1 minute with 10 minute breaks inbetween. However, it would be interesting to read about field tests proving the actual Potenco yo-yo works as intended. If a simple sliding seat could be designed for local DIY production (e.g. two boards with two rolling poles in between) then the yo-yo could even be used in rowing action and put the legs to work, too.
Colin said that for a recharging device to be effective you need a 10:1 payback on the energy expended. They are doing an early test in Uganda (where the XO is not, as far as I know). As I listened to him I thought of all the non-XO uses, especially for emergency/disaster response, camping stores, just having one in your car.
There are plenty of bikes in these countries and most are used for heavy transport (people, bananas). I'm sure someone will hook this up so that foot power can be used.
I don't think the Portenco would work for a "rowing" style actuation. The capacity is too low to provide useful resistance for efficient rowing motion. I suppose you could gang two or three of them together to provide enough resistance though.
Also, it looks like I have concurrence on the vulnerability of the pull-string. With two spare strings packaged in the body of the generator the designers have acknowledged and taken care of that problem in a rich-folks environment. My guess is that once string number three breaks the people the generator is aimed at will be out of luck unless they can fabricate a replacement. I'd be interested to know how tinker-friendly the generator is.
Oh yeah, another way to utilize the pull-only characteristic of the Portenco would be to have them hooked up to treadles so that two generators would be alternately pulled by a stair-climbing motion using the legs only.
Steve, Roland got there first but the Gibson Girl was necessarily more powerful the Portenco. The vacuum tube technology of the time required a fair amount of energy just to get the filaments hot enough to work. Less wasted energy, less generating capacity necessary.
Are you deliberately misspelling P-O-T-E-N-C-O as part of some obscure trolling attempt, or is that just a cognitive hiccup?
Apologies! For my part the po(R)tenco came from an initial assumption that it was a PORTable power source.
DOES ANYONE HAVE POINTERS TO A SITE WITH RELIABLE POTENCO OUTPUT DATA? All this anecdotal speculation is really pretty senseless when a working device exists. It's like urban folklore that can easily be given "Myth Buster" treatment...
EXTRA: I certainly agree with pedal power observations above,especially since (aside from sunshine!) bicycles are one thing Africa is NOT short on. Bike technology is massively utilised all over the continent,particularly in just the developing regions that OLPC is aimed at.
Stan,
Potenco used to have a spec sheet on their website that gave detailed output data, but once we linked to it, they took it down. Sadly, I didn't save a copy.
allen,
Rowing action:
**************
concerning the resistance for rowing action I thought the resistance was adaptive as Colin told.
"It was relatively easy to pull repeatedly, and the stronger the person the greater the resistance and higher wattage generated."
Output tests
************
"Their base line human is an eight year old pulling on the yo-yo device. They even tested the amount of CO2 produced as a kid uses it, as well as calories expended (very few)."
I am glad that Potenco made scientific tests with an eight-year-old breathing through a mask in order to measure gas turnover and CO2 concentration. This is a standard test in sports medicine. It provides exact information about the energy the body is burning while doing a certain activity. If you can also simultaneously measure the mechanical energy output like with a pedal-ergometer or with the yo-yo you can calculate the efficiency of the human body giving clues on kinesthetics used and the level of training of the test person. For the measurement to be exact it should not only be done during the 1 minute pulling but until the pulse is down again or during a one hour sequence of 1 minute pulling and 10 minute breaks. The results have to be compared with values of the test person's rest status.
Obviously Potenco is in possession of interesting test results. They just did not publish it yet. And together with their withdrawal of the data sheet from their web site this seems like strange public relations politics.
> concerning the resistance for rowing action I thought
> the resistance was adaptive as Colin told.
I'm not sure what that means. Electrical generators are, by nature, adaptive. The more load you put on them the harder it is to spin them. Light load, light effort. That's how regenerative braking works in electric cars.
If Potenco has something else up their sleeve I can't imagine what it would be. Maybe a current limiter that prevents the generator from producing more then some maximum amount of power so as not to burn out? I can see someone hooking up every gadget they have to the Potenco and running it with an animal-powered contraption. Without a limiter the generator can generate enough current to burn out its own windings.
As to why they pulled the information from their site, I don't think the Potenco was originally designed for the sort of environment the OLPC is destined for. Consequently, it isn't designed with those environments in mind. Whay should it be?
One fine day Nick Negroponte shows up and dangles the prospect of seven-figure sales in front of the owners.
Would you redesign your niche product to service a market like that? I sure as hell would. I'd take the time to redesign for lower production costs and greater robustness. So they pulled the data so as not to have to explain discrepancies between the old and the new model. Or something like that.
If you get to design the generator along with the charge circuitry you can do quite a bit in the way of optimizing power transfer. But if the design is still broken into systems-diagram type boxes with specified inputs and outputs the prospects are limited.
For example, if the OLPC charging circuit is like all others it will accept a range of voltages and shape the current profile to charge the battery. Increase the voltage and most likely the current drawn will decrease, due to the constant-wattage DC-DC converter inside. Thus, the harder you pull the string, the lighter the load will be and you put more of your energy into simply moving your arm.
For human powered operation you'd want to have the current profile shaped by the amount of available energy (which will vary from instant to instant), and push as much current into the battery as possible when it's available.
The charging current should therefore be a function of the generator voltage, which means a different kind of feedback loop on the DC-DC converter that feeds the battery charge circuitry. In fact, the charging circuit should be integral with the DC-DC converter - I fell into the systems-diagram trap there.
(For information, the systems diagram approach in engineering is the same as reductionism in philosophy - as I am given to understand it - the tendency to reduce everything to identifiable and separate elements and to concentrate attention on each element to the neglect of the whole. It's a powerful tool, and popular at MIT, especially for building large systems with large organizations, but you can do much better in creating smaller systems by taking a step back and looking at how to combine functions.)
Does anyone know if the hardware design (schematic's, mechanical layout, bom, etc) going to be completely open?
Patrick,
It depends on what you mean by "open". I am sure you can hack the mechanics - they even encourage it with the design apparently, but they seem to be on track to patent the technology for their financial gain.
Wayan,
are you sure that the purpose of Potenco's patents is for their financial gain only?
Also the new display technology of the XO is patented. Taking out patents can also be used to protect a technology - and slight variations of it - from being patented by other parties with commercial interests. The important issue is the policy by which licences are granted for others to use that technology. Such licences could be granted for free for charitable use. Or licences fees collected from commercial users could subsidize the charitable usage.
E.g. the display patents might become a strong defense against commercial players trying to conquer the school computing market in the third world by applying vendor lock-in strategies.
And besides, Potenco has a legitmate right to make a fair profit to pay for their past and future development efforts.
Roland,
I have no issue with Potenco making money. Quanta sure is. And I do understand all the ways patents can be used and assigned to protect development projects - OLPC is patenting just for that.
My only point was that I do not expect them to give their product IP away or at a loss.
Colin said they are definitely for profit. They want to succeed, and I'd guess, re-invest in other cool products which might be other types of tetherless power.
I think they are in a second round of funding at this time.
IMHO they'll have a hard time getting a 2nd funding round unless a first DATA round is available! I for one am used to considering technical proposals supported by concrete data & field trials,& hence increasingly view Potenco's offering as flawed. An Australian phrase "All show and no go" springs to mind....
>> Stan, Potenco used to have a spec sheet on their website that gave detailed output data, but once we linked to it, they took it down. Sadly, I didn't save a copy.
Wayan, following up on your posting, I found this on the Internet Archive:
http://web.archive.org/web/20070422024256/http://www.potenco.com/files/Potenco_OLPC_Spec_Sheet.pdf
Might this be the spec sheet to which you were referring?
At last-although specs. read more like a sales pitch than a technical test. That 20-50W statement rather reminds me of new cars claiming 60mpg on their sales brochure...
A simple realistic "kid power" workout is obviously needed,as even most high school age Science Fair projects have better field trial data than this. Give me one for 10 minutes & I'll rustle up pages!
"It was relatively easy to pull repeatedly, and the stronger the person the greater the resistance and higher wattage generated."
Maybe it has a speed sensor, with a set ideal pulling rate. If you are pulling too fast it assumes the resistance is too low and increases it, and contrariwise if you are pulling too slowly.
What I am thinking here is they could have done tests to determine what speed produces the most power over the long term, and set that for the generator. I know that bike racers do tests like this to determine what is their optimal rate of pumping.
It's clever that the XO comes with adult-proof packaging. Not so clever that pills do...
Hi all . . .
One thing that I'm attempting to find out about the XO's power supply is what type of connector is used to interface external power generating devices (the Potenco generator, a solar panel, the suppied AC-to-DC transformer, etc) with the computer. All I have been able to determine is that it's a "12 volt DC connector" but that doesn't tell me much as there is an infinite variety of such interfaces available at your typical electronic store. From the low resolution side views that I've seen of the XO it appears to be a barrel connector of some sort but even this is only a guess. Nobody's spec sheet (OLPC or Potenco) gives a clue. Does anybody here know what particular one the OLPC team chose to use? Perhaps someone that actually has access to an XO would know? If some sort of specification number isn't available then clean close-up photographs would be a good start.
Thanks in advance
Ben
Have you tried e-mailing around a bit? Doesn't seem like the kind of information that'd be covered in a NDA so it should be available for the asking if it isn't findable on the web.
Hi Allen . . .
Yes, one would hope that it's not a trade secret. I can't imagine that it would be. This image gives about as much as I found, so far (note the electrical tape covered wire splice . . .
http://flickr.com/photos/pmtorrone/467379279/in/photostream/
It's a barrel conector of some sort but there are lots of different sizes - and polarity configurations - of these.
I sent an email on Friday afternoon to Potenco
and, hopefully, they'll be back in touch early this next week. I attempted to ask OLPC on their Wiki but couldn't, for the life of me, find a way to bring up a message posting form or even find an email address for them.
Ben
20/20 hindsight has reminded us that XOs take several hours to charge. Thus you would need to use your charger, well, several hours. The time before fatigue indicated in the data sheet mentioned says 10 minutes.
20/20 hindsight has reminded us that XOs take several hours to charge. Thus you would need to use your charger, well, several hours. The time before fatigue indicated in the data sheet mentioned says 10 minutes.
Hello,
does anybody know the e-mail address of Potenco ?
Despite of my attempts to find it i couldn't.
Shall be very gratefull if someone mail the address to me -
chankov@spectrumnet.bg
Thanks
Ivan
info@potenco.com shows up when you use their "contact" page