One of the great features of the Arduino community is the availability of thousands of pre-written libraries that add hardware and other functionality to your projects without needing to write your own code. There are usually quite a few to pick from and your code will often depend on libraries, so the quality of the library you use can be critical to how your code performs. How do you write good libraries or how would you evaluate the quality of the latest library you downloaded?
A question on the Arduino forum and the thread that followed prompted me to try and emulate a mechanical push- or thumb-wheel display update on an LCD module. The technique uses the LCD programmable characters and could be extended to other applications for simple LCD module animations.
I was exploring ways to make a future robot project more appealing and came across a number of articles about animated robotic eyes created to convey expression or mood. This looked like a bit of fun and quite achievable using the LED matrix modules that I have been playing with for a while. Here’s the result.
In Part 1 I described the hardware components and the functionality of the LED clock. This this part, I’ll explore the software required to implement the functionality and seamlessly manage the different user interfaces.
I wanted a create a simple project to test a few ideas and still be useful in its own right. Walking through my local IKEA store, I saw a really inexpensive analog clock (Rusch) and decided that it would provide the right vehicle for what I had in mind.
In the last few projects I completed, I needed to find a way to process user commands arising from multiple input sources. A simple example would be a clock with tact switches and a Bluetooth interface providing identical functionality from either user input source.
For these applications I developed a simple modular and scalable approach that can be applied in other projects.
The amount of RAM an application uses is printed out by the IDE at compile time. For applications that don’t allocate memory, this is a really good guide to how much spare RAM is available at run time.
However, if an application, like any using the Parola libraries, uses memory from the heap, you need to make sure that there is sufficient memory left for run-time memory allocation.
Vertical LED dot displays are not a common requirement, but they can be created using the standard library with a few tweaks to the software.
As I get questions about vertical displays from time to time, I will cover the basic process of how this is done in this short article. Continue reading “Parola A to Z – Vertical Displays”
In the first part of this blog I described building a test apparatus that allows me to experiment with tuning a PID loop controlling a levitating pin pong ball in a tube.
This second installment is about trying different hands-on methods of tuning the loop, understanding how they are derived, and how well they perform compared to each other.
PID (Proportional, Integral, Derivative) control is a classic control algorithm that I have used for a few projects, ending with ‘good enough’ control, without really spending time learning how to properly tune the PID constants.
Time for me to fill in the gap in my knowledge, so in this two part blog I want to capture my learning. Hopefully it is useful for someone else. In this first part I will document the learning and testing rig and software. The next part will be about tuning the control loop.