Arduino with more inputs than the miro pro

[djglish]

Is there an Arduino board that has more inputs than the Micro Pro and less than the Mega series?

I built an adapter for my old Atari 800XL using a script that I found, but it doesn't include the 5 special keys, such as reset, select, option and start. I'm using this with a mini-pc mounted in the old Atari case. I was able to remap those keys to others but it would be great to be able to use the actual ones on the keyboard.

I see that the Mega series has plenty of inputs but that might not fit well in the case (the 800XL isn't very tall). If I did use a Mega could I also utilize the extra inputs to control two joysticks. I have a separate iCode designed board doing this now but it would be good to have everything in one board.

I'd also need help getting this project completed since I have little coding skills.

[flashko]

I can't help you with the whole project but I might be able to suggest ideas for more pins. If it's just inputs, see 74HC165 serial registers, where each chip adds 8 inputs. For more outputs only, see 74HC595, as each chip is for 8, but now the outputs. The two types of chips allow cascading for more inputs or outputs respectively. There are also I2C GPIO expanders such as the MCP23016, which are more expensive but also more flexible.

sn74hc165.pdf

74HC595.pdf

20090C.pdf

[gilshultz]

There are many port expanded modules available. Generally 8 or 16 bit. PCF9574 and PCF9575 are some of the popular ones. They connect with I2C and you can add 16 of the PCF8574 devices but 8 must be A devices (different address).

[djglish]

The serial registers look like they would be way beyond my abilities. I did see that there is an Arduino Mega Pro Mini that would easily fit in my case. I might get this and just add the six inputs that I need for the extra keys for now. Maybe in the future, if I do some reading I can add the instructions for the joysticks. I'm assuming that the board would be able to handle both the keyboard inputs and the two joystick inputs. If I get some more old donor 800XLs I could make a few more of them and possibly sell them. The little mini Windows PC that I'm using is only $100.