Assignment: Pick a piece of interactive technology in public, used by multiple people. Write down your assumptions as to how it’s used, and describe the context in which it’s being used. Watch people use it, preferably without them knowing they’re being observed. Take notes on how they use it, what they do differently, what appear to be the difficulties, what appear to be the easiest parts. Record what takes the longest, what takes the least amount of time, and how long the whole transaction takes. Consider how the readings from Norman and Crawford reflect on what you see.
For this assignment, I wanted to observe the subway fare gates. Mostly out of personal frustration, and to see if there are others who have the same problems as I do sometimes.
My biggest issue with these tollgates is that sometimes my swipe is not readable. I feel like there’s a certain pressure you need to swipe with, or maybe sometimes the swipe reader is broken. When I see a guard about it, they press a button to let me pass without swiping. When a guard is not present, I have to walk to a different entrance and repeat the process. When I’m in a rush and the line for the subway guard is too long, I just bite the bullet and buy a new ticket.
I observed the subway gates for about five minutes. At least three people had to swipe more than two times until their card was read. The traffic was backed up when a woman approached the gate and had to dig through her purse to find the ticket. People are also exiting through these gates, which creates a side-step dance pattern (like when you see a person coming down the hall and you step right to get out of their way and they also step to your right to get out of your way, and then you see them step to your right and you step to their left, and they do the same). A handful of people, from afar, looked like they were not sure which way to swipe the card.
It’s easy though, when swipes do go through– all you have to do is walk through the turnstile. In some other areas, they have the turnstile and also a door so people can’t jump over the turnstile. With that said, it’s also very easy to enter without paying. I saw one lady duck under the turnstile, right in front of the subway guard.
It’d be nice if, instead of swiping our card, it could detect it with RFID. Swiping cards is somewhat difficult because speed and pressure are factored in in some cases. You also have to pause to check that the stripe is facing the right way. Also if it were an RFID, people can throw their bags over the sensor, and not have to dig through their purses or wonder if they are swiping the correct face.
Also I think turnstiles should be one-way only, and there should be a bigger portal for exiting passengers.
But I found it difficult to get an accurate reading. I would weigh each piece and map out the values to the LEDs, and then the next time I put the burger pieces on the FSR, I would get something completely different. Alex suggested that I put a plate with a quarter on top of the FSR so the pressure is evenly distributed. Chris thought it was because the burger was hitting a different area on the sensor every time, so he suggested putting felt in between the two plates to keep it more steady. Even then I still had trouble. Little things would screw up the results, like putting my fist down on the table, or dropping the meat patty instead of carefully laying it down. Tom said my problem is that I need to have four sensors with little rubber feet instead of one big sensor in the middle. I didn’t get a chance to try this out, because I only had one big FSR and the bookstore was out.
Chris and I decided that at this point, I should just shove all the weight in the pickle and have it max out the sensor. I dug up every coin I could find to weigh down the pickle, and turned the man into a burger inspector.
If a pickle is present, he flashes a red light, warning me not to eat this delicious looking burger.
If no pickle is present, a green light glows which means the burger is okay to eat.
Chris suggested a great idea for my final project. I’m going to make more pieces and use them to teach kids about nutrition, and also make a Processing sketch to display calories and other important nutritional data. I haven’t thought about it too much yet, but I’ll probably have a lunch box and the child must pack his own lunch. If he doesn’t meet the nutritional criteria, then the lunchbox won’t close and he can’t take it to school. Or I might build it cafeteria-style, with plastic trays, a buffet line, and lunch lady Doris. 
After I soldered this, I twisted the wires, and soldered the other ends to a header pin. I then hot glued the area around the header pin to form a secure connection, and reduce the stress on the wire.
Then I measured the voltage of different circuits– series and parallel, switch and potentiometer. I spent a good fifteen minutes growing increasingly frustrated because I couldn’t get any reading on the multimeter. A classmate then pointed out that I needed to remove the plastic covers on the tips (doh).
In the help session, I learned that when measuring anything, the multimeter needs to be set at a higher value. For example, if your LED is using 2.5 volts, the dial needs to be pointing at 20. If you have it set too low, then the meter will blink a seemingly random number, and then return to 1. Also it was hard for me to get the multimeter to respond when measuring the voltage of an LED when it was attached to a switch or potentiometer. I had to either press really hard against the legs of the LED, or wrap wire around the multimeter probes.
Below is the photocell wired to the LED. When it’s receiving full light, the LED is bright.
When light is blocked, the LED dims.
I then wired three LEDs in sequence, and had the potentiometer control the brightness of those.
