Nicholas Barry

Light Sensor Watch

Background and Concept:

The original idea was to make something that would replace the nose part of Floral Yu’s design and change the color of the bands based on light level. However, since one cannot look an LCD if it’s on their face without a mirror. I opted for creating a watch like object that changes the color of a LED based on the light level and output the light level as a percent on an LCD screen. Ideally the watch would be less bulky, but that would be difficult without a PCB and a different micro-controller.

My design is a thick bracket that reads out the light level and changes the color of a light strip. There will be a case that surrounds the Arduino, its 9V battery supply and a small breadboard. When the light is bright the LED is cyan, when the light level is medium the light is blue and when the light level is low, the LED is purple, and the light will slowly transition between color values. On the LCD screen it will read out light levels as percentages.

The design is a large case that has Velcro thread through the holes on the edges so that it can attach to the arm. The top is removable and attaches using snaps inspired by the casing tutorial on Brightspace [1]. The Arduino will be stacked atop the bread board and the battery will be in a separated space on the side.

Physical Design:

The 3D design component is a housing for the Arduino breadboard and 9v battery. The Arduino is stacked on top of the breadboard and the battery in a separate segment. The top is attached to the bottom using snaps.

The large hole at the top is for mounting the LCD with 3mm diameter bolts. The larger circular indentation in for the RGB LED, and the smaller one is for the photoresistor. The two slots on the bottom are for two 2in thick Velcro straps which allow this device to be worn like a watch.

Bill of Materials:

PLA
2 x 2in. adjustable Velcro straps like those available here: Amazon.com: YiwerDer 6Pcs 24″ x 2″ Nylon Heavy Duty Reusable Hook and Loop Cinch Straps, Adjustable Fastening Securing Cable Straps, Black : Electronics
Electronics (Discussed in next section’s bill of materials)
9v battery
9v battery to Arduino adapter

Electronics:

Before constructing the Design I built it in Tinkercad using the 2 wire LCD starter as a base [2]. I then used my knowledge from the third Arduino assignment to make the system for getting input using the photoresistor and changing the color of the RGB LED [3].

The purpose of the components and the overall function of the electronics is explained in the video below.

Bill of Materials:

Arduino Uno
8cm x 5.5cm Breadboard
16×2 LCD display
4x 220Ω Resistors
10kΩ Resistor
Photoresistor
Potentiometer
RGB RGB

Link to files (Code, Makerbot Print, Fusion 360 model):

https://drive.google.com/drive/folders/12RhiXyB1-YNiadjOA5qLhqhrAZIBYJO5?usp=sharing

References:

Page by: Nicholas Barry