I am thinking about using an ATmega32U4 instead of the ATmega328P for my laser tag project. The main advantage of the 32U would be built in USB (at the cost of built in serial hardware. Oh darn, I can use software serial. Not a big deal). The 32U is also twice as expensive. The table below summarizes the differences that matter for the laser tag project (there are many differences. I only care about the ones that my project needs. Mainly, programmability and cost; both chips have the functionality that I need).
|Price (Quantity = 1)||$6.04||$3.05|
|Price (Quantity = 100)||$3.42||$1.73|
|Barebones Arduino||$22.95 (adafruit)||$29.95 (adafruit)|
But, of course, there are similarities. Both chips have 32 kB of flash memory for storing programs, and both have hardware timers, PWM and enough output for the basic laser tag game that I want to implement. Therefore, since both of these chips have these properties, this information has no effect on my decision because it does not help me distinguish which alternative is better.
Both processors are supported (can be programmed with) the arduino IDE, which makes my life a lot easier. Since the 32U doesn't need an FTDI chip for USB to serial conversion, it saves about $15 for the cost of the board. As of now, I should use the 32U instead of the 328P, since it will make the device cheaper by implementing USB communication on chip.
Dangerous Prototypes posted an article about Paperduino, an arduino Leonardo (Leonardo uses the 32U) clone. It has a cool tutorial on putting a paper label onto the board as well, which is a nice touch. For more information on the 32U4 and the Leonardo, the guys at arduino posted a great article.