Tuesday, February 19, 2013

Class topics of interest


Examples of successful/ unsuccessful development work with a technology focus

In every career path, people inevitably learn from their mistakes.  In a way, I feel that making unsuccessful designs, effectively making mistakes, is the most important aspect of developing a successful product.  Therefore, unsuccessful development work is necessary for successful work.  On the other hand, an unsuccessful products in developing countries can have detrimental effects by not only wasting money, but also discouraging populations about what products will be available for their future.  I see these two situations of unsuccessful design to be very different, one is caused by creativity, trial and error, and the other is caused by carelessness.  I am interested in discussing what makes development work successful and unsuccessful, and if unsuccessful work is due to an inherent design flaw or a neglect to consider who would be using the product.
Furthermore, we have already discussed the challenge engineers face of designing for people who are removed from themselves, and I would like to see how the most successful development work has tackled this problem.  Before looking into the answer, I have a hunch that the greatest success will come from those who have truly engaged with the targeted population and involved them in the design process.  If a community cannot get excited about a product, and does not feel like it is their own, I believe that it will be much harder for a product to have success. 
The lack of technology in developing nature indisputably contributes to a lower living standard, and I see it as developed nations’ responsibility to act as a catalyst for nations to develop their own technologies.  I would find it very interesting to look into the correlation, if any, between successful / unsuccessful development work and giving technologies to countries versus helping them develop / create these technologies themselves. 

Wednesday, February 13, 2013

Solar Panel Testing

-->
To understand the variables attached to solar panels, we explored how different distances, positions and surface areas affected the voltage and current captured in the solar panel.  Additionally, we were tasked with finding the resistor that will maximize voltage and current.  We used a 50-watt bulb to serve as the sun, and offering a light source.  In a 100% efficient solar panel, all 50 watts would be captured and converted to useable power.  We measured the current to be 54.9 milliamps, which converts to .055 amps, and the voltage at .5 volts.  To get the wattage produced by this current and voltage, we would multiply the two quantities, .055 * .5 = .0275 watts.  Out of a possible 50 watts, only .0275 watts were captured, yielding a 5.5*10-4% efficiency.  This efficiency would be the case if the wattage the bulb required was exactly equal to the wattage it put out.  However, the bulb its self is not 100% efficient.  We noticed that the bulb generates a significant amount of heat and in conjunction with the amount of useable light given off by the bulb, the light that reaches the solar panel is much less than 50 watts.  The average cheep solar panel is around 10% efficient, and knowing that the wattage of useable light available to the solar panel is much less than 50 for a variety of reasons, we can conclude that the panel is probably around 10% efficient.  The panels are not as horrible as we first calculated, but they are will clearly not be used by NASA.  The next experiment we conducted using the solar panels was to add resistors to the circuit and find the resistor that yielded the highest current and voltage.  We tested a total of 8 resistors and fount that they all were very close to the ideal current and voltage, that measured with no resistor in place.  The resistors ranged from 10 ohms to 100 killi-ohms, however we focused primarily on resistors with orders of magnitude from 1 killi-ohm to 100 killi-ohm.  Within the primary resistors we tested, our average resistance was 26.6 ohms and we found that there was an average current of 51.8 milli amps and average voltage of .58 volts.  Ideally, we would have liked to find a resistor that yielded a current and voltage equal to when there was no resistor present, 54.9 mA and .50 V.  However, because no resistor will be ideal, we will choose the resistor with the current and voltage reading closest to 54.9 an .50 to be our "best" resistor.  The 10 ohm resistor yielded a current and voltage that was significantly different from the other data compiled.  Originally, I suspected that this point was an outlier; however, upon further examination, this may not be the case.  According to the mathematical formula, V = IR ( Voltage = Current * Resistance), a larger resistance will yield a higher voltage, which is consistent with our data, the voltage of the circuit is smallest with the smallest resistor.  Although the formula V=IR can be rearranged to say V/R = I, which would suggest that a smaller resistance should yield a larger current, if you have a small voltage, the current should be small as well.  The last test we conducted was to test the effects of "bird poop" on the current and voltage of the solar panel.  We found that the effect of covering one spot on the solar panel had the same effect on the current and voltage as covering half of the panel.  Each component, current and voltage, decreased dramatically when just a speck of the panel was covered.  We concluded that this is due to the interconnected-nature of the solar panel. 
Resistor
Current
Voltage
No resistor
54.9 mA
.50 V
1.2 k ohms
53.9 mA
.49 V
4.7 k ohms
54.2 mA
.48 V
10 k ohms
49.1 mA
.47 V
15 k ohms
53.9 mA
.48 V
22 k ohms
49.1 mA
.47 V
33 k ohms
50.8 mA
.48 V
100 k ohms
51.8 mA
.48 V
10 ohms
38.8 mA
.38 V

  

Monday, February 11, 2013

Jodie Wu


I was not in the audience for Jodie Wu’s talk about her experience with Global Cycle Solutions, so I have done my own research on the products that are in place and how they have impacted the communities in which they are implemented.  The main goal of GCS is to “disseminate affordable, quality technology for villagers around the world (gcstz.com).” In her lecture, Jodie Wu focused on her experience designing and developing the bicycle-powered corn sheller.  She began the process in2009 at a MIT design lab with may different prototypes and possibilities that could be implemented half way across the globe in Tanzania.  As with any project, she faced many challenges; however, the challenges of implementing a new technology in the third-world brought an even more unique experience.  Her biggest challenge is seen through her favorite quote, “technology without reach is technology without impact,” which describes the necessity of accessible and practical technology that can become a common good without a dramatic change in a citizen’s way of life.  In order to make the implementation of any new technology successful, the villagers must be able to sustain it by themselves and become proficient in using the technology.  To overcome this potentially detrimental problem, Wu sought out to train one villager and molding them into the village encyclopedia; someone who knows the technologies on a level deeper than their surface and can teach his fellow citizens how to use and fix them.  Having a village encyclopedia creates the opportunities for individuals to become more educated and reach higher levels of entrepreneurship than were possible before the technology entered their lives.  The technology not only makes farmer’s lives easier by introducing an alternative to the two previous methods of maize shelling, (hand shelling which is only able to bag 1 sac a day, or whacking during which much of the maize is destroyed) giving the farmers a way to fill 10 to 15 sacs a day, but it also creates more jobs in the community through the production and training process.  Wu mentioned that the entire experience of designing and implementing the Sheller and other technologies has been a very rewarding process. 
Although the lecture did not focus on much past the corn sheller, I looked through the Global Cycle Solution’s website and found that there are four main technologies that are currently being used by a total of 30,000 families in Tanzania: a solar-powered light and phone charger, the maize sheller,  a Bicycle-powered kiwa phone charger, and a motorcycle phone charger.  The solar light and charger is currently the world’s longest lasting light with a phone charger attached to it, clocking 30 hours of light from one day’s charge, and it is very durable, making it a good investment.  The bicycle-powered phone charger will charge the phone as you ride your bicycle, taking a task that is very common in every community, especially those in the third-world, and giving the mundane task an exciting addition.  There is no extra time needed to charge the phone, and it is cheap and easy to lean how to use.  Similarly, a motorcycle charger was implemented to charge a phone as you ride the motorcycle. 
Jodie Wu and Global Cycle Solutions have received a lot of publicity in the United States and abroad.  Wu was named to Forbes ‘list of 30 under 30, the greatest minds in business, she was a TED fellow in 2011, and even has the bicycle-powered kiwa phone charger on display at the Smithsonian museum in Washington. 

Sources:

Wednesday, February 6, 2013


The Water Carry 

Because running water is not a reality in many third-world countries, different methods have been developed to ease the burden of transporting water that must sustain families for a given period of time.  We explored four methods; carrying water on your head, a tumpline, the hand carry, and a q-drum roller.  Going into the exercise, we were told that the hand carry was the only method that is not currently employed in a third-world country, so I was expecting it to be the most difficult and least practical method.  Carrying water on my head was without a doubt the most intimidating and the least familiar to someone from the first world; however, with a little practice, I began to convince myself that having water on the top of your head was probably the most secure method and would be attached to the least amount of future physical problems.  The tumpline also seemed very practical, seeing that the weight of the water was spread out over many points of the body.  Additionally, if a waist-strap is added, the tumpline can resemble a hiking backpack where the weight is placed on the hips, one of the strongest parts of the body.  The last method, the q-drum seemed like a first-world solution; pulling something behind you, the least physically taxing, and very easy to take breaks.  When actually performing the exercise, new pros and cons to the different methods arose.
            A course that consisted of slightly uneven pavement and a small trek through wooded terrain can hardly compare to walking miles though “back country,” but it was good enough to get a sense of which methods would be completely impractical and which could stand a chance.  I began the exercise with the head carry.  Needless to say, this was my first time carrying gallons of water on my head, so my form clearly had some flaws; however, I found that in order to be successful, one must have good posture and walk at a constant pace to prevent the water from sloshing around in its container.  Ideally, the head-carry would be a hands-free method and leave a person able to multitask, and because the water (or whatever good someone is carrying) is on top of a person’s head, it is safe from thieves or contamination.  The major cons of the head carry are that it restricts the movement of the carrier, meaning that they must remain upright and change speed/directions at a slower rate.  Next I tried my hand at the q-drum method.  I do not have a dog, but if I did I believe that rolling the q-drum would be similar.  At times when I was moving downhill, the drum would speed up and roll in front of me, then other times, like walking up stairs, I would have to use nearly my entire body weight to get the drum moving.  If all surfaces were paved, flat, smooth and not crowded, the     q-drum would be a very practical method of carrying water; however, this is not the case.  The most disturbing problem that arises is that the opening of the drum, where the water goes in and out, was a centimeter from the ground.  The hygienic aspect of the q-drum was clearly not considered…ew.  The tumpline came next, and with it was the reality that it was probably the most taxing on the body.  Good posture did not make carrying the water any easier, in fact, a slouched position yielded the best results.  Although the weight was easier to distribute, the best tumpline designs required the most materials and thus would prove the most difficult to maintain or replicate.  The last method of water transportation was the 1st world hand carry.  While making my way around the course, I was constantly trying to find a way to carry the water other than with one hand by my side.  I was putting the handle in my elbow crease, using two hands and even switching hands/arms regularly.  As a result of my movement, the water inside the tub was constantly moving and splashing up along the sides of the container.  Without a lid, a significant portion of the water would not have made it the entire journey. 
            From this experiment, I think that the head carry is the most practical, followed by the tumpline.