Product tear down – Portable CD Player

Some notes from dismantling an Alba portable CD player:

– 8x Philips head self tapping or thread forming screws.
– Different sized screws used, but all with the same head. One screwdriver.
– No seal between the two halves of the main casing.
– Button modules are heat staked in place.
– Screen is attached to plastic casing with adhesive. No obvious alignment features.
– Blobs of glue and tape used for cable retention.
– Micro switches with injection molded buttons
– Small, stick-on foam pads control the feel for the button and hinge at max travel.
– Battery cover flexes for insertion.
– CD reader module held in place with shock absorbers.
– CD reader module travels on plastic rail.
– The lead screw controlling the position of cd reader module has a spring contact, so the module can be moved by linear force.

Foam Board Modelling

This tutorial outlines a method for making a foam board cube with very neat edges:

Below are some notes from my own attempt:
– The material used was 5mm thick foam board.
– When cutting the 45 degree edges, it was better to use a spacing of 4.0mm rather than 5.0mm.
– It was better to leave a small gap between the edges of the squares when taping the cube together.
– The masking tape was too sticky and it nearly damaged the foam board. A different masking tape may solve this problem, but it might be better to avoid tape altogether.
– The PVA glue took too long to dry. I would probably stick with a hot glue gun.

Arduino Counter

This simple circuit was created to count the number of times that two buttons have been pressed alternatively.
The buttons must be pressed one after another to add +1 count, so the circuit could be used for counting the number of times a door or lid feature is opened and closed. The counting can’t continue until the full open/close cycle has been completed.
The number of button presses is displayed in the serial dialog box and also on a 16×2 LCD.

Link to the code is here: Lid_Counter_03

Data Logger for Thermocouple and Load Cell

The aim of this project was to develop the Arduino data logger to read a variety of sensors.
The first step was to develop the code from the last project and give additional functionality to the data logger.

Develop Data Logger
The following changes were made to the data logger code:
– The filename of the data file was changed to: “datalog.txt”
– The serial prompt was shortened from “file opened for writing” to “data stored”.
– A clock function was added.
– The clock recorded the start time of the test, as well as the time of each reading.
– Headings were added to the data file: “Light reading” and “time”
– Wires were connected from the arduino to the LCD: SDA to SDA, SCL to SCL, VCC and Ground

These tutorials were used:
Tutorial 1 – Video
Tutorial 1 – Code
Tutorial 2 – Video
Tutorial 2 – Code

The new data logger code is here: datalogger_shield_light_01

The arduino was setup to log data from a Thermocouple. A tutorial was used but it was not followed exactly. The circuit did not use a capacitor and the pins had to be changed from 9,10,13 to 7,8,9 to prevent interfering with the SD Card. The delay in the “loop” had to be changed from 1000 to 735 in order to get a 1 second delay between readings.

Thermocouple Tutorial Video
Thermocouple Tutorial Code

Wire setup:
So – Digital pin 8 (purple)
Cs – Digital pin 7 (blue)
Sck – Digital pin 9 (green)

Code link: datalogger_shield_thermo_01

Load Cell
The arduino was setup to log data from a load cell.
The load cell was calibrated using code from a tutorial. A stepper motor weighing 221g was placed on the load cell, to and the “calibration factor” was adjusted until the correct value was given. The “calibration factor” was changed from -7050 to +403 and the units were changed from lbs to grams.

Load Cell Tutorial

Wire setup:
SCK – Digital Pin 2 (yellow)
DT – Digital Pin 3 (orange)
VCC – 5V (red)

Code link: datalogger_shield_load_01

Data Logging Shield

This code was created to test out a data logging shield for arduino.

The arduino was connected to a photoresistor and LCD screen. The analog input of the photoresistor was monitored and recorded to an SD card at regular intervals, with the LCD screen showing the values as they were being recorded.
When the code is first run, it creates a txt file on the SD card with the filename “TEST.txt”. The data is then logged to this file.
The next step is to add clock functionality that can record the time the measurement was taken.

The code is here: datalogger_shield_code01

XY Robot

This robot was made with 3D printed parts and components from Open Builds part store.
The belts are fixed to the aluminium frame components and the robot moves relative to the belts.

The first version of the code uses four buttons to move the robot back and forth is the X and Y axis (two buttons for each axis). The code is here:

V-Rail One Axis

I recently bought some V-Rail parts and have been trying out different configurations for one-axis robots.
In the first configuration, the stepper motor is attached to carriage and the belt is fixed to the rail.
In the second configuration, the motor is at one end of the rail with a smooth idler pulley at the other end.
V-Rail 01
V-Rail 02
V-Rail 03