Time goes by way to fast! This weekend I rebuilt my Keurig auto filler. I looked back at my old posts and the original post was just over a year ago! Version 1.0 has worked flawlessly but was way too big and bulky. I also never outlined how to build your own. So here it goes…
- Dual Float
- DPDT relay
- 4x2x1 Project Box
- Prototyping board – I bought this pack and used the 3cm x 7cm board. You can probably find a single board at Radio Shack
- 4 x PCB Terminal blocks
- 4.7uf capacitor
- 12v Solenoid Valve
- 12v Power Supply
- 1/4″ plastic tubing and connectors: you can find these are your Local Home Depot
Putting it all together:
I built the auto filler based off of this pump control circuit. I made one modification to this. It is VERY important that you do this or you will toast the float! Place the 4.7uf capacitor across the relay coil. This will prevent the relay from oscillating rapidly as the float switches open and close. The capacitor keeps just enough charge to prevent this. Here is a photo and their description:
This diagram is for the circuit to fill a tank, using two normally closed oat switches and a two pole
changeover relay. The upper switch will be closed provided the liquid is below that switch point.
The liquid falls until the lower float switch closes and energizes the relay. One set of relay contacts connects the pump to the supply and the other maintains the relay on-state, while the level rises towards the top switch. The relay will be held in the energized state until the top oat switch opens, so releasing the relay and cutting off the supply to the pump.
I tapped into the reverse osmosis water faucet under the sink for my water supply. You could also tap into your freezers water line if it has an ice maker.