How much time would you spend on your I2C I/O PORT Expander Project
Your project of using Rpi to drive 260 devices using an IO expander is a very complex project, for sure not for the faint of heart newbies.
I already have 5 years hobbyist experience in Arudino and another 5 hobbyists years experience in Rpi. I still need 6 months to learn the basic knowledge and skills to do a complex project like yours.
If you are also a hobbyist like me, you might need as much time. Of course it also depends on you basic electronics knowledge, and if you have a home lab with necessary tools.
You might like to visit the following websites to know more.
Free Electronics Text Book
Setting Up a Home Lab
https://www.allaboutcircuits.com/textbo ... -home-lab/
The 555 Timer
https://www.allaboutcircuits.com/textbo ... -8/555-ic/
Teardown Tools - Element14 Workbench Wednesday
https://www.youtube.com/watch?time_cont ... 4oVzS4afQ4
Upgrade Your Solder Station (for professionals only) - Element14 Workbench Wednesday
https://www.youtube.com/watch?time_cont ... R0S80xMIuk