I saw someone make an EMF detector on youtube, so I decided to try making one myself. I don't have a bar LED, so I'll use regular LEDs.
features:
- detects EMF
- the higher the EMF, the more LED's light up
parts:
- 9x red LED's
- 9x 330 ohm resistor
- 3.3M ohm resistor (I used a bunch of smaller resistors and connected them in series to get 3.3M ohm)
- 1x probe to detect emf (a wire)
After learning how to use a piezo element as a vibration sensor, I decided to give it some real life use. The piezo sensor will detect the number of knocks on the box. Once the correct pattern is detected, the box will be unlocked. I'll be using a servo motor and a plastic hook that I found as a lock.
Features:
- a piezo element will be used to detect the knocks
- Once the correct pattern is detected, the box will be unlocked.
- to re-lock the door, simply press the button. The lock will be engaged 10 seconds later
Parts:
- 1x piezo element
- 1x servo motor
- 1x push button
- 1x 10k ohm resistor
- 1x 1M ohm resistor
- an external power source (I used a 9 volt battery, salvaged the input jack and a 9v battery holder)
Piezo Vibration Sensor
Lock Socket
Lock Unlocked
Lock Engaged
This is a very basic and cheap way of unlocking a door lock through vibration. Instead of using duct tape, I could screw in my servo motor(and the plastic hook) directly onto the box, but I want to reuse my motor for future projects.When I gather the appropriate materials (different box, a reliable locking mechanism), I will make a better version of this project, and perhaps add more features.
My piezo element was salvaged from an old stationary bicycle. The piezo element was originally used as a buzzer but I gave it some purpose by turning it into a vibration sensor. I learned that the value of the resistor connected to the piezo element (in parallel) will affect the reading. After trying out different resistors, I noticed that a 1M ohm resistor seems to give the best result.
I learned how to use a flex sensor and a servo motor.
Features:
- control a servo motor by simply bending the flex sensor
- the motor's movement direction can be adjusted by bending the flex sensor
- bend the sensor to the left, the motor will spin clockwise, and vice versa
I decided to upgrade my LED thermometer into a digital thermometer. A 4 digit segment display (salvaged from an old satellite receiver) will be used for this project. I also added an option to display the temperature in kelvins.
features:
- temperature can be displayed in different states(degrees Celsius, degrees Fahrenheit, or kelvins)
- to switch between states, 2 buttons will be used to achieve this (degrees Celsius is the default mode)
default mode: the temperature is displayed in degrees Celsius(in this case, 26°C)
when the top button is pressed, the temperature will be displayed in degrees Fahrenheit(in this case, 80°F).
when the bottom button is pressed, the temperature will be displayed in kelvins(in this case, 299 K).
You will notice that the temperature is slowly increasing after 19 seconds. I transferred my body heat by simply touching the temperature sensor.
This was my first time using a segment display and it was a slight learning curve. The segment display is not very bright since I connected a large resistor (330 ohm). I don't have any smaller ones unfortunately.
Another simple project, designed to help me get familiar with the use of joysticks.
features
-The corresponding LED will light up in the same direction as the joystick
- when the button is pressed (joystick comes with a pushbutton), turn all LED's on
Parts Used:
- 8x red LED's
- 8x 330 ohm resistor
- 1x 10k ohm resistor
- 1x joystick (salvaged from a PlayStation controller)
The only difficult thing in this project was to unsolder the joystick from my playstation controller. This is very difficult, since there are 14 pins and I had to use a gigantic soldering iron.
features:
