The micro:bit is a small programmable board, created by the BBC that can be used for a variety of tasks, once programmed. The BBC have branded it as the true successor to the BBC micro. The DfE gave one to each Year 7 student in 2016 in an attempt to get more children coding. It’s very appropriate to upper KS2 and it’s possible to code it using tablets and a coding language that looks very much like Scratch.
There is a class set of micro:bits available for you to borrow. This is now at Ashfield Park Primary School, Ross-on-Wye. You can contact them to request this here. Please note that you will need to collect and return them from / to the school.
You’ll find a wealth of material on the official website of the device.
Additionally, there’s a sheet of starter activities here that work well with the components we’ve included with each of the kits you can borrow: a-selection-of-microbit-projects.
You’ll find a whole host of other possibilities if you search online.