Quote:
Originally Posted by MetroMPG
I also love that you're not not blowing the project budget on mounting hardware/shields.  |
Thanks
I like this setup because the LCD is secure, the pins are still easy to get to, and it is low profile when sitting on the dash. Also it would be simple enough to add sides and a top after things become less experimental, and stain or paint it if desired. But hot glue and bits of wire and a chunk of balsa are good enough for me. Just need to sort out the buttons.
FYI, radio shack had a bag of 4 little buttons for $2. I'll probably mount them flush with the LCD face on the sides with some long leads for now. Or maby along the top right where it would be easier. Yah, I like easy, that looks like a plan.
Edit: easiest mounting turns out to be to jam them in under the LCD. Now how many? 2, 3 ,4? Each button takes a pin
4 buttons should be easier to navigate. I.e. a select, 2 scrolls and a back.
3 buttons isn't too bad either, I e a scroll in either direction (so you don't have to cycle through all the options if you pass it) plus a select button, but "go back" becomes a thing you have to select.
2 buttons is the easiest to hook up and simplifies the design choices. Harder on the users as there's lots more clicking, but not a big deal.
Ok Pin check: We don't have any sensors plugged in yet or buttons (or a piezo speaker), but after the LCD we have:
4 pwm pins
2 "serial" pins 0,1, I think we can give up 0, but TX might be useful for debugging.
6 analog/digital read pins
(yep, sorry blinky fans, I took pin 13 for the LCD)
So that leaves us 11 pins without buttons or car signals.
we need 3 digital read pins to talk to the car. vss,inj,ign power.
and each button will need a pin, so maybe 4 there.
piezo speaker for another 1, would be good for the "your mpg is dropping" alert.