|Pretty (but dumb) LED Matrix|
However a few defects are obvious too:
- the LED spacing is wider than on stripboard, which can make patterns harder to discern
- the interface split between anodes and cathodes is the same as the original, for no good reason
- it now uses 16 gpios!
The first and second of these are my fault but the last could have been mitigated by adding an LED driver, such as the MAX7221 to the design:
|MAX7221 DIP package|
This particular chip requires only a couple of capacitors and a single resistor to function (see the circuit here). Also it is cheap, less than €1 from China and has a mature Arduino library. It could comfortably have fit in the space occupied by the resistors on the left of the picture. On the downside, it requires a 5v supply. (The Arduino playground has a lot of information about it.)