sevenseg

Is a little demonstration project that shows how to use a shift register like the famous 74HC595 and a darlington array ULN2803 to drive a 7 segment LED display.

Requirements

Software

The software is written in C++ based on platformio. You can also use it directly with the arduino IDE or may even port it to avr gcc.

Hardware

This section covers the needed components and the circuit diagram

Components

• Arduino UNO R3 (any other arduino will do)
• 74HC595 shift register to reduce the amount of pins needed from the microcontroller
• ULN2803 darlington array to drive the led segments. The shift register could not sink enough current.
• Nine 160 Ohm resistors
• One 100nF decoupling capacitor

Circuit Diagram

General use

The software itself is just a demo application. It features a simple countdown from 9 to 0 and you can display multi digest numbers with multiple seven segment displays with a built in function. The schematics provided here do only show the simple case with one display. But it is very easy to daisy chain the shift registers. The needed code is already there.

License

Copyright 2018 Christian Rapp

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.