Solar Technology Lessons

Our first week on site has been dedicated to working through and creating a manual which is essentially a "How To" guide for solar technology on a small scale.  (See our newly updated manual page on the right-hand side of the page!)  Our lessons began Tuesday and continued into today, starting with Ohm's Law and the relationship between voltage, current, and resistance, the photoelectric effect, and power.  We went back and forth a little bit about whether or not to include the photoelectric effect since it moves beyond information you need to know and into the theoretical realm.  However, ultimately Julian and I decided that providing an understanding (a very basic one) about where the current generated by a solar panel comes from, and explaining phenomena like a solar panel providing less current but the same voltage on a cloudy day, was worthwhile.  The discussion of power, too, we decided would be very useful in order to speak to the safety of a circuit.  By connecting a ten ohm resistor that is rated for .25 watts to a twelve volt battery (which V = IR claims should have a current of 1.2 amps passing through it, and the power law P = IV says should produce a power of 14.4 watts), we demonstrated that if your components have greater power passing through them than they are rated for, then they will burn.  Electrical safety and making good choices in selecting components and wires is a big part of what we decided we need to cover, because hacky and intuitive training in electronics doesn't provide those aspects, while they are incredibly important when you draw large amounts of current and use large amounts of power, as is possible with the batteries and solar panels that we're using.

Junior holds a ten ohm resistor prior to its smoky demise.

The second day we taught each of the components that are used in our node (operational amplifiers, diodes, LEDs, zenerdiodes, voltage regulators, variable resistors, and fuses), and spent the next two days practicing circuit building and circuit design.  The way our lessons work, everything that we say is understood by maybe one or two students, and then Junior, the “spokesman” of the Lwemode Youth Center, translates whatever we say into Lugandan.  We meant to print out our manual each day for the lessons for the day so that people could follow along and not be forced to remember the functions of the long string of components we breezed through after hearing them only once.  However, power has been out in Kalisizo (and actually all the way up to Masaka, apparently) since Tuesday, so we haven’t been able to print anything after the first day.  Also, on that first day, we realized that a printed manual in English isn’t super helpful unless you’re one of two people in the Youth Center.  So we’ve been searching for a way to create a translated version.  Anita (the Program Director for FSD Masaka) said she could connect us with a translator in Masaka who normally charges 15,000 shillings per page.  It’s kind of pricy ($6 USD/page), but when you remove diagrams from our manual it won’t be that long, and we can budget out of our seed grant for that expenditure.

Junior translates the lesson for the rest of the class.

Going over circuitry.

Going over circuitry.

Figuring out the diagram.

Aside from language barriers, the toughest part of this week has been the transition from understanding the components and what they do to what it means to physically connect them.  Even looking at the diagram of a circuit, the group has been having a lot of trouble understanding how the connections show up on a breadboard/circuit board, how a single row is connected, but columns aren’t, and how to connect different rows on a breadboard with wire.  They don’t seem to like the method of diagramming circuits because circuit diagrams don’t show the shape of the circuit.  The diagram shows which components connect to which other components and how, but doesn’t tell you “skip three holes, then stick in the right leg of the 1K resistor,” which is what Junior told us we should write out for them today.  We don’t want to shift to drawing circuit diagrams as schematics of the connection holes on a circuit board and which legs go in which hole for a couple reasons.  First, that would take forever to draw, either by hand or on a computer, and secondly, it makes it hard to communicate schematics accurately.  We want to be available after the summer in case the group has questions, and if they are trying to build a specific circuit it’s much easier to send a normal circuit diagram which would eliminate the possibility of sending a schematic that gives some components too much space/not enough space.  It’s hard to draw up an accurate schematic if you’re not looking at the circuit board or the components that will be used.

Many hands make light work!

Success!

Figuring out the multimeter.

Going over circuit components.

The Lugandan lesson.

Building a cell pone charge measurer.

This dislike of drawing circuits made designing one difficult.  Given a switch, two resistors with different resistances, an LED and a battery, we asked them to construct a circuit which can either power the LED in a bright mode, or a dim mode.  Without drawing the diagram of the switch pins, they never really ended up getting the problem finished (Julian ended up giving them lots and lots of “ookumaniyas” or “hints”), and it’s a lot easier for them to look at a circuit and understand how it works when you explain it, than it is for them to create, design, or connect the circuits.  That seems to be a normal thing though when teaching people basic circuitry; understanding is much easier than problem solving.

What we really want them to have those is a growing passion (which is certainly coming along) and some basic experience with circuits to understand the necessary concepts of current, voltage and power. They really are the keenest students we have every seen. So focused and so fascinated. Typically  we say one sentence about a component, Junior or Betty translates, all the members have a 5 minute discussion in Lugandan with each other (all pointing at diagrams/components) and then when it goes quite Junior looks up and says, "mmm, proceed." We then repeat the process. Quite fun to watch. In the next week we are going to, finalize the theory part of our manual, install our first panel and set up the first node. Exciting times.