How Big Can My Python Script Be?

We all know that the micro:bit has limits. The specs (available either on WikiPedia or the ARMmbed site) show that the memory limits are:

• 16kB RAM
• 256kB Flash 

That sounds like a decent amount of memory - it's not in the gigabytes range of even your most modest modern PC or Mac, but for an embedded processor a total of 282kB is not too bad. So surely we can load massive Python scripts onto our micro:bits, right? Wrong. The hard limit for a Python script is just a snip under 8k. Try and copy a script file larger than that and it will fail. Why is that?

What are .hex files?

You must have come across .hex files by now. Every time you compile a program on the micro:bit website you end up with one. You copy it to your device and the program runs. Every time we post a project on this blog we include a .hex file. Every time you hit the Flash button in Mu it silently and secretly creates a hex files and automatically copies it to your micro:bit. But what are .hex files, how do they work and why should we care about them?

Tilt Maze

Son and I recently went off for a boy's weekend at the Grandparents. We knew that we'd be stuck on trains for a good few hours so we decided to take along the micro:bit so that we could embark upon our own Train Jam. Son chose to work on a maze game where you have to navigate your way to the exit. He also wanted keys and doors to make it more of a challenge.

We thought it might be tough to make this a fun game on such a limited device so we decided to keep things simple. With only 25 red LEDs it was tough to think how we could show the various elements of the maze. We decided that:

1. The player would be a very bright pixel and always in the middle of the screen. The rest of the maze would scroll around you.
2. Walls would be dim pixels.
3. Doors would be slowly flashing pixels.
4. Keys would be rapidly flashing pixels.
5. The exit would be flashing in some cool way that made it look enticing.