Smart meter interaction - help please
So here is my query with what I want to do.
I'm developing a module to do with energy.
I have a number of items on scree e.g. TV, computer, kettle, fridge/freezer, etc. the usual consumer/electrical items you would expect to find in a UK house. Each item will have a value, e.g. TV=10, Fridge/Freezer=20, Kettle=5, Computer=15, etc.
The screen will also show a smart electricity meter.
I want the learner to be able to click (select) any of the items, so when they click the TV (10), the smart electricity meter shows 10. When they select the Kettle (5) the meter changes to 15; when they deselect the TV (10) the meter changes to 5, etc. What this is in theory doing is showing how the cost or energy consumption goes up ior down depending on what items have been turned on (selected) or turned off (de-selected).
The smart meter will be a graphic that has a window for the numbers which I guess would be a text variable - basically this is a + or - type of calculation for each item.
Any ideas how I would achieve this please?