Archives for category: physical computing 1


Schematic — Tlc reference

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<a href="">pcomp1 : IR ranger_1</a>
<a href="">pcomp1 : IR ranger_2</a>

Binary Clock

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The first image is a schematic that helped me connect the parallel series LEDs with the Chronodot.

<a href=”Light_Time_workingVersion”>pcomp1 : binary clock</a>


For this project, we are required to use a sharp IR sensor (an infrared range detector) and make something that exhibits calm technology. I started thinking about a specific location in the building of Parsons on the 10th floor where 4 separate areas meet in one small space. Because there is so much traffic going in various directions, it is hard to see if someone is walking, or sometimes running, around the corner. I’ve noticed that people accidentally run into each other because of the blind spots created by the corners of the walls. So, the role of my project is to prevent human collision and create a visual indicator that will indicate if someone is approaching the area and from what direction. Because the IR sensor picks up a very short distance in range, I need to do some testing and figure out where to place the sensor, giving it a jump start (few seconds) to detect that a person is moving towards this small area.

Images of area & prototype sketch:

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Some things to consider

Look & Feel:

I need to figure out exactly where I should set up the IR sensor and the visualization. The lights need to be noticeable, but not right above the doorway. One question I have is regarding color and how I can prevent using red and green as indicators. I am not sure if this will work, but maybe with the right placement and use of fading in and out of the LEDs. I am thinking that the LEDs will slowly animate from low to high (nearby to too close).


Input : sharp IR sensor

Output : some sort of LED display that visualizes a person approaching this area. I will be using a PWM driver, TLC5940, which will allow me to use up to 16 LEDS and create a calm gradient or wave of color as the person walks towards it. (which will be shown in the opposite space)

For this assignment, we were asked to use the New Haven Display – (NHD-0220D3Z-NSW-BBW model)

First I connected the LCD screen to my arduino, using 5V, ground and the RX pin (RS232 Serial input port)

Here is a sketch of my ascii characters: (I translated the bit numbers to hex)

Here’s a video showing my custom characters :

ascii code

In class, we extended this assignment and worked with a couple different libraries.

This video shows what I programmed using the Software Serial Library:

code : lcd ascii with library : software serial

Here’s a video showing how I used the New Soft Serial Library:

code : lcd ascii with library : new soft serial

Assignment: linearize sharp IR sensor ; change logarithmic curve to a linear curve

IR sensor_code

Assignment : LED meter with shift resistor (MM74HC595)
Using the serial print values / analogRead from the photocell, I got a range of 235-770 using a 2.2k resistor.

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This video shows the smallest range possible, making the photocell extremely sensitive

LED meter with shift resistor_code
useful tutorial

in class, we asked to use a potentiometer and/or photocell to collect serial data from the LED values.

next assignment: LED Meter with shift resistors

I will be using this analog data as output data to a SIPO 74HC164 shift resistor, controlling 8 LEDS. The final step is to great a bar graph, measuring high to low values, 0 being all LEDs are off and 8 being all LEDS are on.

analog data from photocell : range (235 – 770), using 2.2k ohm resistor

Project Assignment: The rules for Light and Time assignment are to use only Light and Time. You are allowed to have one pushbutton if you want (option).

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Create a small ‘thing’ that incorporates sound and dimming LEDs using the tone() command and the analogWrite() command.

dimming_tone code

Simple Code Lock.
Hardware: 4 pushbuttons and 2 LEDs.
Firmware: Some sequence of button pushes must be made in order to turn the ‘unlock’ LED on. If the sequence is incorrect, the ‘locked’ LED will turn on instead.

push-up / push-down schematic & circuit:

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