# Graphite Variable Resistor

Hi!

This week I created a switch that is itself also a variable resistor.

It turns out that graphite is conductible. So I hooked up an LED and watched how I got a different brightness reading on the LED depending how far away my power and ground wires were to each other. It makes sense, the farther away the two wires were, the more resistance and therefore the less output on the LED. The closer the two wires were to each other, the less resistance, and the brighter the LED became.

This is possible without software because it is totally controlled my where the power and ground are physically to each other. The next step would to be figuring out how I could create an interesting result to how much output is created by the LED.

Also, graphite is hardly conductive, it took a lot of effort to create a conductible image. I’m wondering if I can create a variable resistor from graphite based on the intensity of graphite…?

Movie on 2-24-14 at 12.36 PM

# Don’t Forget Your Keys (Part 2)

So to be 100% honest I forgot to take a picture of my circuit before I disassembled it and I just didn’t feel making it again just to take a picture. However, because my project this week tied in to last weeks switch I just reused that picture. So I’ll just describe everything and I swear it works. The idea was that if the keys were on the hook and the door was closed one LED would flash on and off. If the key was on the hook but the door was opened the LED would stay on constantly and a buzzer would go off. If the key wasn’t on the hook though nothing would happen. To keep things simple though I just used two panic button switches instead of using the key and door switches. Below is the code for this. Also I couldn’t get the buzzer to work so I just used two LED lights instead.

void setup(){
pinMode(8,INPUT);
pinMode(7,OUTPUT);
pinMode(13,INPUT);
pinMode(12,OUTPUT);
}
void loop(){
digitalWrite(7,HIGH);
digitalWrite(12,LOW);
delay(1000);
digitalWrite(7,LOW);
digitalWrite(12,LOW);
delay(1000);
}
else {digitalWrite(7,HIGH);
digitalWrite(12,HIGH);}
}
else {digitalWrite(7,LOW);
digitalWrite(12,LOW);
}
}

There are always more books to be read. But how would you know when you should clear some off your reading list, without a bright blue light to tell you?

This switch is pressure-sensitive. Wires are attached to a square piece of aluminum foil with an “O” shaped foam cutout, and this is in turn folded into the last page of two books. When the books lay on top of each other, they are not heavy enough to compress the foam and activate the switch. As you add more books on top of the original two, the added weight activates the switch.

See it in action here on Instagram.

# Securing the Butt Pocket

Many people I know/see on the street walk around with their cellphones and wallets in their back pockets. I used to be one of those people (still admittedly, am sometimes) until last summer where I lost two iPhones, and I grew increasingly aware of the security I needed to maintain to ensure these expensive phones would no longer be lost/stolen. But now, butt-pocket users, fear no more – my switch adds security   to your life style.

My switch involves two plates that will line the pocket and when touching, the switch is “on.” The current is interrupted when a wallet or cellphone is placed between these two. Because one of the two plates is spring loaded with paper-clip springs, when the phone/wallet is removed, the plate will spring back and reconnect the current, and the switch will turn on. When the switch is on, the LED will light up, but also a little motor will vibrate to notify you that your stuff’s gone. Hopefully one day, when people start using Samsung watches or Google glasses, a message will be sent to those devices.

# “I’m going to bed” switch

So the concept is when somebody sits or lays on the bed the light would turn on. I tried using too pieces of metal glued seperately on the bed frame and the matress, but that ended up really hard to control (but a workable concept).

Instead, I taped the button on the one edge of my bed where it’s would be pressured when weight is put on the bed. I soldered wires together with the switch, and fixed it on the bed frame. The mattress is too soft for acturally pushing down the button, so I taped a starbucks lid onto it, to give it a hard surface where the button would touch.

# where the f**k are my keys

When you place your keys on the hook, the LED lights up. The hook is made a bit springy because of the wire inserted behind it, so the weight of the keys hanging weighs it down enough to touch the aluminum foil plate behind it, attached to the “wall.” This sexy box is meant to simulate a wall that the hook and keys would be on. Ideally, this setup would be located near your front door to remind you not to leave your keys behind, as my boyfriend did after class last week and called me to whine about being locked out.

# Light (and a coffee break) at the end of a reading

(I think I cheated because there’s a human hand involved. Oh well, here goes…)

I had some coffee cup sleeves lying around (I was in Intro to Sculpture last semester and to avoid paying more than the required \$350 studio fee, I recycled and repurposed my materials) as well as a book I’ve been struggling to read for a class this Tuesday (how typical). Then I had an idea: Why don’t I turn the sleeves into bookmarks that help me track my progress in completing my reading assignments?

So I spent 3 hours attaching a gangly wire (which may be, regrettably, ugly and distracting) to the Starbucks sleeve, to be used for a page I start off reading, and the other to The Bean sleeve, for a page I want to read up to (the goal being, on the same day). When I reach “the finish line,” I would tuck The Bean sleeve into the Starbucks sleeve, which would turn on the pretty blue light! Then I would help myself to a dirty chai from The Bean because I deserve it — reading is an intense workout.

(Don’t play around with the sleeves and turn on the light if you haven’t finished reading for the day.)

-Ashley

# Toilet Seat Switch

For my switch I decided to use the toilet seat as a a button pusher. In order to do this, I needed about 6 feet of wire. The button was taped (heavily) to the top of the toilet seat and the wire ran from the toilet across the floor, outside to the hallway located on the other side of the bathroom door. When the toilet is in use and the seat is up, the blue light outside turns on!

Here it is:

The taped button on the top of the toilet seat.

The entire toilet with the wire running down to the left…

…all the way to the arduino set up in the hallway outside

IMG_2941

Toilet Seat Switch

And finally, the toilet seat switch in use!

The light is on- the toilet is in use!

I figured this switch would come in handy in instances in which someone was using the toilet and forgot to lock the door. I have two roommates, so this happens all the time. Ideally, I would have liked for the arduino/light to be stuck onto the wall next to the bathroom door but I figured that would be impractical (plus, I used up all the tape sticking the button to the toilet.) Maybe next time…

I found that the sensitivity of the button was kind of all over the place. This made it somewhat challenging to figure out a good spot to stick it on the toilet (hence why so much tape was used.) Sometimes the lightest touch would switch the light on- other times it took a force full push of the toilet seat. However, after a good amount of tinkering, I found the right spot!

# Kiss Switch

Though my switch isn’t the most practical, and admittedly a little cheesy, hopefully you guys will like it. Because our discussion of first kisses last Monday, and because it’s February so Valentine’s day decorations are inescapable, I decided to run with the theme. As per the assignment, the switch isn’t activated by using fingers, but rather a kiss.

In order for the LED to be activated, the two lips must touch. I could show it to you in action on my cat or something, but that would just be awkward, so I will just hold the two ends instead.

Movie on 2-2-14 at 11.07 PM

(the videos don’t seem to be working right now, maybe it’s just me?)

Since it is not physical lips touching, I envision this as something that could be developed for digital kisses, maybe sending one via bits and bytes to a loved one who is far away, where the LED is a way of signaling that, though it is not direct, you have made contact with someone across the world.

# It’s only weird if it doesn’t work

Congratulations to the Seahawks. Anecdotally, its clear that defense wins championships. However, can the ‘hawks really take 100% credit for their victory? I say neigh; instead, the Arduino-powered Seahawks D-fence activation button should receive some of said credit.

Whenever the Seahawks needed a defense boost, anyone in the room simply needed to push and hold the button in order to activate the boost. Clearly, it worked very well:

Awesome right? Here’s how I made it…

I called up my best friend from middle school to help me solder and glue the some wires to the button we received in class:

Then, I made a series circuit that flashed blue and green Seahawks colors:

Unfortunately, together, the lights were too dim for my intended purposes, so I made a single-LED setup. I found an empty box, cut some holes in it and covered it in a thin wrapping paper, and put the setup inside:

See how it works in the video below:

# Time to Check Out

I’ve been working at the NYU Law Library and part of my job includes checking periodicals/magazines/law journals out to faculty members. When an item is to be checked out, it is placed in a wooden box that can be seen from the table my coworkers and I are stationed. I had an idea to make a switch that notifies me and my coworkers when something needs to be checked out using an LED light. The items can be anything from a few pieces of paper stapled together to a large 600 page book. For my switch, I used a photocell that I soldered to two longer wires. The photocell alters the luminosity of the LED light. When the photocell is covered, the light dims. This switch accounts for the periodicals that would not weigh enough to set off a compression switch. I covered the wires with electrical tape and flattened them so the photocell can lay down in the box. When an item is put into the box, the light dims alerting my coworkers and I that something needs to be checked out and is then done in a timely manner.

# NaCl (aq) Switch

These two switches use salt water to turn the LED on or off. Originally, I wanted the switch to be connected to an hourglass filled with salt water, so that every time a drop of water fell, the LED would light up. I tried to recreate this effect in two ways: one with a water bottle,  and the other with a overhead container of water. The idea of a water-hourglass seemed funny to me because, although it would look like it was keeping time, the rate flow would of the droplets would slow down (and the LED would blink at irregular intervals), thus making the hourglass a pretty inaccurate timepiece.

# Teacup Switch

This switch will protect the wooden table by revealing if people are using coasters or not. The bottom rim of the teacup is lined with copper ribbon so if the user fails to use a coaster, the switch is activated when the cup touches the table (where the wires are located), completing the circuit and turning on the LED. It’s not entirely realistic, seeing that the teacup has to land directly on the wires in order to activate the switch, but at least it works as long as the cup touches the wires somehow, regardless of the exact position it is set down in.

# Water Weight (or Don’t Forget Your Keys!)

From the beginning I wanted to do something with water for my switch. However, I wasn’t sure how to make it a true switch at first. While chatting with friends about this project one of them gave me the idea to displace the water somehow. This idea led me to this setup. The circuit itself has two wires going into a cup of salt water. One under the water level and another just above. The switch is a lever (in this case a hanger) with equal weights placed on either side. When weight, such  as keys, are added to the side above the water, the weight dips into the water, raising the water level enough to complete the circuit. By giving a visual signal you’re more likely to remember to put your keys on the hook and take them with you making it less likely that you’ll lose your keys.