I’m making a project for my 6 year old son. Basically it consists of 3 parts.
1) A part to generate electricity (at first, a solar panel, but maybe later a wind turbine too).
2) A part to store the energy; probably 4xAA rechargables.
3) A part to consume the energy. Probably a series of USB sockets with switches so he can plug in lights, MP3 player, speakers, etc.
Everything will be together in a console so he can monitor what’s going on. (The solar panel will be outside.)
I’m not an electrical engineer so I have some questions.
First, I want to provide visual feedback to show how much energy is being produced at a given point in time. The solar panel I like provides 6V at 200mA max, which I guess is adequate for charging the batteries. I want to have a kind of meter which lights a red LED if the current production is, say, 3-4V, a yellow LED for 4-5 and a green for 5-6. What kind of circuit would be suitable. (Having read the solar panel thread I might upgrade to a higher nominal voltage unit, but the same rule applies; I want my son to be able to position the panel, or just consider the weather, and note the effect on input.)
Also, I want to display the current charge of the battery pack, again similar to the above.
Also, I want to display how much current is being drawn from the battery by the consuming devices. For this I thought a small LED numeric display, 3-digit, since the load should never exceed 999mA. If you can get a multimeter for < 5 quid, can you just buy a circuit for approximately the same?
I’m flexible about either using several different coloured LEDs, or an array of similar colours, or even some prefabricated part if anyone knows of something that would do the trick. Any ideas would be welcome.
If anyone could point me in the right direction I’d be very obliged.