I must ask you, which is more badass? A single Arduino blinking a matrix of LEDS? Or an epic tower of Attiny85's, working together, blinking themselves and becoming the matrix?
Which is more expensive isn't the question. Price is everything, but that is posted at the end of this post.
So I have had this project in mind of an "Attiny85 communication system" for quite awhile. I would like to produce this product to offer to the community, but first how about getting the communities feedback. If it is something they would consider as a consumer and what quality I should incorporate.
The base unit will consist of multiple (probably x2) separate Attiny85 boards that are designed in a manner that have the ability to interconnect with each other horizontally and vertically. No wires needed for communicating. These will be designed in a way you can stack as many as you like given you have the power/availability. If you want to go for a flat and vertical design. Somewhat like Legos, via female and male headers. Each Attiny board will be 5v regulated, so every 2 boards need 10v-15v (power is limited to each layer).
5v pwr in // Layer 3 | Processor 5 < - takes blink and moves another servo | missing board
10v pwr in // Layer 2 | Processor 3 <- takes blink and moves servo | Processor 4 <- receive - does something
10V pwr in // Layer 1 | Processor 1 <- blinks LED, HIGH and sends signal up^| Processor 2 <- sends signal
The entire purpose of interconnecting is this could be used for communicating via the I/O's to perform a task, or you can take a piece off as a separate Attiny85 board. Something of novelty but what else did we buy an Arduino for? 1-2 boards (or layer) will have an AC adapter, the other boards can be powered via the Vin/GND pins. The base unit will also come with a "programming shield" compatible for the Arduino UNO or other alike devices.
Roughly estimated net price is:
$21.50 per layer (2 Attiny85 boards)
+ $3.50 per programming shield