For a couple of recent projects we have been asked to provide interesting and informative display units. We decided to build a unit which can be used in a number of different applications. It was designed to look good, be able to show graphics and text, have a couple of switch inputs and be configurable for a variety of uses. The end result was so useful, we decided to produce this design and a kit of the main parts.
The unit comprises:
More information about using the LED dot matrix display can be found in this blog post.
To keep development time to a minimum, an arduino is used as the 'brains' of the unit. This is a development board based upon the ATMEL 328 microprocessor chip. Our units use the less-expensive Xino, an arduino clone from Ciseco. Any Arduino compatible board should fit into this display unit (except the MEGA range).
There are numerous open-source examples available for the arduino, hence development time is very short. We have developed a simple clock unit with temperature history display as a sketch to get you going with the use of this display, but the final use is left up to your imagination.
A specially designed interface PCB has been produced for this unit. There was some extra space on the interface board, so we decided to add a number of components which might be useful for your project. These include:
The prototype PCB has just bee made and tested. While it did not work first time, with a few tweeks the unit is working well. Here are some photos:
The XRF can be seen with the white antenna. The coin cell battery keeps the real time clock running.
As usual with a prototype - there were a few wiring changes required...
We now need to produce a production double-sided PCB.
Here is the final circuit diagram for the board:
Right click to save the image for higher quality.
|BT1||BATTERY||20mm coin cell|
|U2||REAL TIME CLOCK||PCF8563|
And the PCB design layout.
****kicad PCB - TO DO, not yet finalised***
The hardware is mainly two pieces of frosted acrylic plastic which are cut out using a CNC machine. The Xino and LED display bolt onto the plastic and spacers are used to hold the two pieces of plastic together.
These are the parts required for this LED display unit:
***image of parts***
This project is a work in progress. This is a list of essential and useful changes which need to be made: