i have some knowledge about IOT and have engineering knowledge so my idea is to make hotel without Recepion only user go to door and scan bar code send money to hotel wallet when all Done door can open using phone for 24 hour .
about engineering side i can do it . but how
1) make wallet auto check value and when only right value happen make action .
2) what can do if user send higher or lower amount ?
3)how can make wallet auto check prices because bitcoin price changes fast and cant edit it manually
Well that's actually a great idea. We got 24/7 shops with food (without employers) just machines so that might be a good project.
1) With a simple code you can do that. A good idea would be using a raspberry or an arduino.
2) That would be done on the code, in case the amount is not correct it will refund. A good solution would be HTTP JSON-RPC calls to manage the wallet.
3) There are plenty of websites that has API where you can check the price of bitcoin.
If you're realling going to do this, i can help you on the coding part.
Good luck.