Pretty happy with the progress I made on the workout timer this week. Rotary encoder control feels very smooth and big digits make a difference.

Progress so far is on GitHub with more details on my previous post. Lots more to do this weekend.

Made some good progress on the workout timer tonight. I have been coding for Arduino for years but I had never bothered to learn the class-based architecture. It takes a bit of getting used to, but being able to organize methods into classes like I normally do at the day job is delightful. I ended up designing a simple and clean architecture for the LCD menu system, as well as the timer itself. As a bonus, I got the large digits working!

A little bit about the large digits: These LCD screens are pretty simple. They essentially have 5x8 blocks that can be filled in using a byte array. This handy tool is great for generating custom characters. I also found this Instructable to be very helpful.

Unfortunately, these characters need to be written to the screen’s memory, and that’s very limited. On the version I have, I only have space for 8 characters. Thankfully, that’s just enough to be able to generate all digits from. I just had to find a bit of a hack to get the large timer colon.

Another thing I worked on was a stable rotary encoder class. There has been some great work done by the community on this, with tons of example code and libraries. Unfortunately, there is almost too much content, and everyone seems to have a different solution to the problem. After dabbling with a few libraries and not getting great results, I found this clear and concise Instructable on the topic and integrated the straightforward implementation into a class-based architecture.

To top it off, I merged this with a standard software button debouncer implementation and ended up with a nice little reusable class for tackling encoders. I am planning to add more “gestures” to this, such as long press and double click.

My progress so far is in this Github repo.

Started work on a little side project: A workout timer. I need a simple timer during morning workouts and this is a good challenge for it.

Requirements and problems to solve:

• Smooth rotary encoder feedback (suprisingly hard)
• Large numbers on LCD
• Object oriented menu system
• Battery powered and rechargeable

Built a prototype board with LCD, encoder and Arduino for easy testing. Encoder implementation with interrupt pins already working nicely. Next step: OOB menu system.