Anyone good at building circuit?

**powerofdeath** · January 10th, 2015, 06:02 AM

Hi, I am in this class called Robotics and Lasers Technology class in Highschool. Our project is that we have to develop a some sort of Water Level Indicator. Basically, there are three wires in a cup that are connected to LEDs. When the cup is filled by 33%, Light A is supposed to turn on. When is cup is filled by 66%, Light B is supposed to turn on, AND light A is turned off. When it is entirely full, Light C will turn on and Light A and B is turned off. Me and my partner have been researching, and all we found was when it get filled, A turn on, then B turn on and A stay on, then C turn on and A/B stay on. It is not what we wanted. Any suggestions?

Edit: Also if we drained it back to 66%, Light B is supposed to turn on and C off. Same with A.

**powerofdeath** · January 10th, 2015, 04:47 PM

bump (since fm is at night)

**Helz** · January 10th, 2015, 07:32 PM

Give me the schematic and I can probably tell you whats what. Im no pro in the field but I work enough projects on hack-a-day to know my way around a schematic.

**Dark.Revenant** · January 10th, 2015, 10:58 PM

Put some voltage regulation on those water wires (such as a wheatstone bridge hooked into an op-amp) so you get a reasonable swing from ~0.5V to ~3V, stick them into a microcontroller like a PIC-12, and program it to turn on one LED at a time when the voltage is at a certain level. Easy as cake.

If you're a communist and hate microcontrollers, you can also do this with a couple BJTs to switch between LEDs.