Arduino 2-Digit 7-Segment Display Counter
This month’s Arduino project is to build two 2-digit 7-segment LED display circuits and sketches, one that counts up and one that counts up using mini push buttons. The next posts will explain the circuits and the Arduino sketches.
Materials:
- Arduino Duemilanove
- 1 2-digit 7-segment display (I got a 50-piece LED display grab bag
for better value; the one I used was configured as shown) - 2 Mini push button switches
- 9 Resistors, 100 Ohm
- 2 Resistors, 10K Ohm
- 2 2N3906 transistors (PNP)
- 1 Solderless breadboard
- Jumper Wires in assorted lengths
Sketch for counting up without buttons:
Continue Reading »
Arduino Lilypad: an Account of Coolness in 4 Links
- Jacket 1: a jacket with turn signals that lets people know where you’re headed when you’re on your bike: http://web.media.mit.edu/~leah/LilyPad/build/turn_signal_jacket.html
- Jacket 2: a jacket that both heats and cools based on one’s body temperature: http://www.instructables.com/id/How-to-make-a-Heating-and-Cooling-Jacket/
- Shirt: this cool shirt features an RGB LED that changes color in response to motion and tilt: http://web.media.mit.edu/~leah/LilyPad/build/accelero_shirt.html
- Scarf: this is no ordinary scarf! The interactive passion sensing scarf detects the presence of another scarf wearer nearby and sets the color of an RGB LED to either blue (lonely) or red (passion): http://www.instructables.com/id/Arduino-Lilypad-Interactive-Passion-Sensing-Scarf/
The Lilypad at the Official Arduino website: http://www.arduino.cc/en/Main/ArduinoBoardLilyPad
Controlling a Seven-Segment Display Using Arduino Part 4
The third and final Arduino sketch uses bits to represent each segment and is a reduced code version of the previous sketch (1,210 bytes for sketch #3 instead of 1,852 bytes for sketch #2). A ten element array holds a byte for each number 0-9 that specifies what segments should be lit (pin low). Bit 0 corresponds to segment A, bit 1 to segment B and so on. In order to display the number 1, segments B and C need to be lit, so that is represented by the value 0b1111001. Function “lightSegments” reads these bits in sequence and sets the corresponding segments accordingly.
Controlling a Seven-Segment Display Using Arduino Part 3
The second sketch cycles through the numbers from 0 to 9, but only increments the display counter each time a button is pressed. Note that this code includes simple debouncing by introducing a short delay when the Arduino detects that the button has been pressed.
Controlling a Seven-Segment Display Using Arduino Part 2
This month’s project is a simple program to display the Arabic numbers using the Arduino and a 7-segment display.
Parts list:
Controlling a Seven-Segment Display Using Arduino Part 1
A seven segment display is composed of seven elements that individually on or off can be combined to produce simplified representations of the numbers 0-9.
There are two types of 7-segment displays:
- Common Anode with all the LED anodes connected together. These need a display driver with outputs which become low to light each segment. The common anode is connected to +Vs.
- Common Cathode with all the LED cathodes connected together. These need a display driver with outputs which become high to light each segment. The common cathode is connected to 0V.
The segments in a 7-segment display are referred to by the letters A-G, as shown in the picture. Some displays have a dot to allow for the representation of a decimal point.
