Introduction: Simple Bench-top Solar Tracker (1-axis)
As a summer project we had 7 students make solar trackers. The students started with zero to little coding/circuit/arduino experience and were able to complete the project in 20 hours, the first 10 of which were spent doing the starter projects out of Arduino book to get familiar with the necessary sensors and actuators. The sequence of practice projects were the following:
1) LED circuit --> LED with button --> LED with 2 buttons in series/parallel (To get familiar with circuits)
2) "Spaceship Interface" (to get familiar with arduino inputs and outputs)
3) "Love-o-meter" (to get familiar with the serial print function)
4) "Mood Cue" (to get familiar with the servo motor)
5) "Crystal Ball" (LCD)
6) "Light Theremin" (Light Dependent Resistors)
Once the practice projects were completed, the students were tasked with making a 1-axis solar tracker. At this point they had seen examples of all of the needed code with the exception of a bit taken from another Instructables solar tracker project. Overall, this is a fantastic way to introduce students to coding, circuits and DIY devices in a reasonable amount of time.
Step 1: Materials
This is a good project for beginners because of the relative low cost of the components.
- The Arduino Starters Kit with Manual
- Arduino Uno board and cable
- 2 bread boards (only 1 is included in the kit)
- Servo Motor with arm attachment
- 2 light dependent resistors
- 2 4.7 kOhm resistors
- 1 decoupling capacitor
- LCD screen
- Variety of connecting wires (not shown in picture)
- 1 4V solar panel
- 1 5"x10" piece of cardboard
- 1 small box
- soldering iron and solder
- masking tape
- box cutter
- wire stripper
- wire cutters
Step 2: The Circuit
The solar tracker utilizes 2 small breadboards. One breadboard is for the solar cell, LDR's and servo and the other supports the LCD. We tried to fit everything on one but it was too heavy for the motor to spin the piece of cardboard and did not have enough space for all the components. The circuit diagram shows all the connections. The solar panel is represented as a 9V battery in the diagram because we could not find the solar panel option in the circuits.io.
The students become familiar with the LDR setup by working through the "Light Theremin" project in the Arduino Beginner's kit, the LCD connections via the "Crystal Ball" project and the servo motor from the "Mood Cue" project.
For a majority of the students there came a point where they had to decide to take everything apart and re-do the wiring so as to create more freedom of movement between the base and the piece of cardboard that sits on the motor. This should be looked at as an iterative step in the device design and the teacher should welcome the students to undertake it. After coming this far in the project and being so close to finishing, the students will most likely be enthusiastic about making their device the best that it can be.
Step 3: The Code
A large part of the code (found in the circuits.io code editor) was taken from a previous solar tracker project posted on Instructables. Thanks thediylife! The chunk of code having to do with resetting at night was taken out to simplify it for the students. After having done the beginners projects, all of the students were familiar with the code and could edit it without much help. The LCD part of the code was added by cutting and pasting directly from the Arduino "Crystal Ball" sketch.
Step 4: The Assembly
This is a good starter project for students because it only requires some cardboard, tape and a box cutter. The top assembly consists of a 8" by 4" section of cardboard that is folded in the middle to make a support for the solar cell and the light dependent resistors. The plastic arm connector for the servo is taped to the underside of one of the folded sections so it can be placed directly on top of the servo motor. A breadboard is placed on the inside of the crease of the support to integrate the LDRs and the solar cell into the circuit. A small box is used to house the arduino and the LCD display. A rectangle the size of the the servo motor is cut into the top of the box, roughly in the center, and the servo is placed inside. Behind the servo insert, a small hole is cut out for the wiring from the LDR/Solar Cell breadboard to connect to the Arduino. On one the long side of the box , a 1.5" by 3" hole is cut near the bottom for the LCD to be seen. The LCD is connected to a second breadboard located next to the Arduino. The Arduino/LCD assembly is situated in a way so that the LCD is seen on the outside. A small square is cut into one of the short side of the box for the USD power cable for the Arduino.
Step 5: The Company
K12 Maker Integration helps teachers integrate high tech maker tools into their classroom. We are committed to meeting the specific needs of elementary and secondary school educators as they expand their classroom resources to include coding, circuit building and making. We specialize in tools such as: smart bit, Arduino and Raspberry Pi microprocessors to incorporate Next Generation Science Standards and take STEM project-based learning to the next level.
Contact us if you are interested in discussing how to take your school to the next level.