As the electronics lab has been getting better equipped and I have also started working with children at different grades and from different schools at the lab. This has given me a chance to spend more time at the lab, work on different projects and also get more confident on handling larger groups. Here is a look at how the Xth grade electronics classes morphed over time:
1) One area: I had started classes by asking everyone to work on one thing on a bread board e.g. getting a seven segment display to work with a counter, using the 555 timer to generate a clock. The classes were somewhat structured with at least 1/3 of the time being white board based. This helped in getting the ground rules of how to read the pin configurations of ICs, LED displays and how to go about connecting them together. It gave a clear focus to the class and helped me give instructions that could be helpful to many students at the same time. It was easy to manage their questions as they were limited.
I also used to throw in, one new thing a class, e.g. thermocouple, demo of AC-DC, that kept the interest of doing something new each class.
However, with just one thing to work on it was difficult to keep the interest of the entire class and about 1/3 of the class were not always present: either there was an enthu cutlet in their group that did all the work, or it was not engaging enough for a student in a class and the lights were on but nobody was home.
2) Chaos Rules: To break the monotony of highly structured classes I had attempted letting people take anything in the lab and open it up. For about two or three classes the students opened, pried, de-soldered on old TV screen and whatever other equipment I had accumulated over the yrs. The TV bore the brunt of their salvaging and they extracted the enamel wire from its various components with much glee :). There was a marked difference in the confidence of children to build something, knowing that if something went wrong, they could always take it apart.
Although, this gave them a sort of undo button, beyond that not much happened. They didn't necessarily want to know more than the name of something the pulled out (as they were not using it). Is this something good to remove?
Yes, its a high voltage capacitor, it can take up to 200 V.
Great, whatever, lets desolder it.
After a couple of these classes I sat the group down and asked them to list what they had learnt. They said they enjoyed it and learnt how to take something apart, but it stopped there.
3) Two projects: As we started working on the Arduino I transitioned to two section classrooms. In hardware I asked them to solder what they had built before a seven segment display to a counter and wire it up so that it had a common interface. I had asked the software group to wire up the display with resistors to the Arduino so they could count inside and display the digits.
One of my goals was to demonstrate the difference between hardware and software. With the hardware I wanted to string a bunch of counters and show that you can, in principle, extend it beyond what Arduino is capable of (limited by number of outputs). For the software group, I had planned to count backwards as well and demonstrate flexibility that software provides when used along with hardware.
They learnt to solder with a clear goal. The software group that was wiring just the LED with resistors with the Arduino were able to get their projects to work in a couple of classes. The tricky part for them was to take the wires and order them as a bus and solder them to a connector. Soldering wires to a 1 space apart connector is a real test of soldering and their work got neater over time.
The hardware group that had to do the wiring realized that it was much more difficult than breadboarding. As they were learning soldering only one of them was able to complete the board completely and they used the solder for too long and the counter chip burned out.
I was able to order some general purpose PCBs with horizontal tracks which would make the connections much more easy and one group that had really put their heart into this has taken up and are doing it again with the new boards.
4) Organized Chaos:
After some introspection, I felt that the kids still wait for me to walk them through every step of the way and my time becomes the limiting factor on how much gets done. I felt they had learnt enough to warrant more independent work.
Over the last three classes I broke the class into groups that were clear about what they wanted to do and started chipping at the rest of the students who had not been as involved.
I have fundamentally changed my attitude to allow myself to be less useful and let the students explore more (ok struggle) on their own while giving a general direction or goal.
Here is an example of what they did in the last class:
1) There are a few kids who have taken what they do more seriously and are working with the Arduino to build an instrument to detect the speed of falling objects.
2) Another is building the electronics for a model of a traffic light (R, Y, G) coupled with a timer that counts down the time with 2 or three digits (again with the Arduino).
3) There is a game to take a loop across an electronics maze and one group is working on a buzzer that will trip and keep ringing once a wire touches the maze (till it is disabled).
4) One group is working on soldering a counter in hardware with counters. They were the closest to finishing the soldering assignment but their chip burnt out due to excess heat. They are now learning how to use sockets and put the chip in once they finish soldering.
5) Two groups were working on two solar torches that I have from friends that I fixed, but the batteries had gone into deep discharge that the solar panels could not recharge. They tried to understand the panels, measured the voltages and tried to replace the panels with power sources that would charge the battery. Hopefully, once they charge the batteries we can re-engage the panels and things would work.
6) One student is working on trying to get an inverter to work. He fixed the fuse, tried to fix an LED that was bust, but it bust again. This week he learnt about relays (from group 3) and was able to check that those still work on the inverter.
Given the limited time (1-1/2 hrs a week) that these students have, perhaps, there can only be learning if they are motivated, exploring and thinking on their own. Progress has been slow, but I can feel the progress. Here are some conversations I overheard and had with the students:
1) One student in group 5 telling another - I'm fixing something real, this is one class I really felt I am accomplishing something.
2) Student: Sanjeev we were able to do nothing this class. Why can't you spend more time with us?
Me: Really. You didn't learn to compile code and write into the Arduino.
Student: You didn't help so I had to figure it out by myself. But, that's not learning.
Me: How about what to do with the LDRs?
Student: You just gave us the sensors and asked us to figure it out. We were so confused. We just characterized the LDRs with and without light and know that it changes from 3 kOhm to almost an open. We are not sure how to use it, but if we put it in series with a 10kOhm resistor we get from 1.5 V to 4.5 V.
Me: Ok, do you think it can be better?
Students: We don't know, but maybe if we increase the 10kOhm resistor and lower the lower voltage. This will help the Arduino trigger properly as it needs as close to 0 and as close to 5V as possible. We can't really explain it, can you explain what's going on....conversation proceeds right through snacks break, but they don't care and want to get it right in the next class. I skip snacks too.
I am having a conversation about design choices (granted simple ones) with Xth grade students from a school catering to village children. Feels like progress to me.
Finally some pics from my class.
|Udavi School Xth Grade Electronics|