good shop for raspi and arduino projects

a lot of what i use in my projects comes from this store at the  link, Sertronics. 

i am always looking for suppliers of interesting stuff i can use for projects and experiments, both mechanical and electronic. if anyone knows any good suppliers feel free to share.

useful digital simulator, on line.

i havent played with this much yet , but it looks like it could be a good learning tool for students.
if you need some kind of digital similator try this one. im not sure how big a circuit it can handle but has half and full adders, should be able to build the basics of a processor..

https://simulator.io/