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Step 1: Parts: the Solenoids
Solenoid valves have a few important attributes:
- the type of voltage required to activate them
- whether they're open or closed when they're unpowered, and
- the size or flow rate they will support.
Step 2: Parts: the Plumbing Bits
If you use a connector like the one in the first picture and your solenoid valve is plastic, you might want to try to find a 1/2" rubber washer, as going from brass to plastic can leak unless it's very tight. The adapter in the second picture has built-in rubber seals.
Step 3: Parts: the Electrical Bits
You're also going to need some wire. I had some spare speaker wire sitting around, and it was perfect for this project. I used about 12' of it, but that gave me plenty of slack to reposition the pedal.
Finally, you're going to need a power source. For this Instructable I used a pair of battery holders (one that holds 2 AA batteries, and one that holds a 9v battery (giving us 12V)). You can find these at Radio Shack or Fry's, or a similar store. You can also use a 12V DC adapter (a.k.a. "wall wart") if you'd prefer. The instructions will be the same, regardless, but if you use a 12V adapter, make sure you have a GFCI outlet installed.
Step 4: Tools and Accessories
To make this Instructable as accessible as possible, I have done all of my electrical connections by twisting the wire and wrapping with electrical tape. If you have the means, I would recommend soldering the connections, but I wanted to show that it wasn't necessary.
You will also want a bowl to catch the small amount of water that will come out when we disconnect the hoses, and a towel handy just in case. Also, some sort of lighting for under the sink will probably make this much easier.
Step 5: Ready the Solenoids!
Next, grab half of your wire. Each of my pieces was about 6' in length in order to give me plenty of room to place the pedal where I wanted; you can adjust this for your project. Strip about 1" off of each end, and twist the wire up. Loop the wires through the contacts of the solenoid (see second picture). If you're using the solderless method, twist these up, and place a bit of electrical tape over them. If you're soldering them, then twist them up and solder them in place.
Finally, it will make installation easier if you wrap the wire around the valve (see third picture), just in order to keep it out of the way.
Do this for both solenoid valves. You're half way done!
Step 6: Install the Solenoids
Ok, now that we have that bit of unpleasantness dealt with, we need to find the shut-off valves for the faucet. These should look a bit like the third picture below. Turn these off, and verify by turning on the faucet (test both hot and cold!). Once they're turned off, position your bowl under one of them and disconnect the hose running from the faucet to the valve. Shake out any remaining water, and repeat for the other side. Make sure you keep track of which hose was connected to which valve. If they're not already labeled, a bit of masking tape and a pen could save you some heartache down the road.
Take your first solenoid assembly, and attach it to the valve and the corresponding hose. It's ok to coil your hoses, as long as the coil isn't too tight. I started by attaching the assembly to the hose running to the faucet, and then once that was secure, I attached it to the valve. Make sure you don't kink the hose as you tighten it. Repeat for the second valve. I made sure to position my solenoids "upright", so that if there were any leaks, they wouldn't come into contact with my electrical connections.
Turn on each of the shut-off valves and make sure you don't have any leaks. Water will only be flowing from the shut-off valve to the solenoid right now, so that's the area to focus on.
Step 7: Connect the Wiring
The next part will sound complicated, but it's very easy. Starting at the top of the picture and working counter-clockwise, we're going to:
- connect one set of the wires from the solenoid to the black wire of the AA battery pack
- connect the red wire of the AA battery pack to the black wire of the 9V battery pack
- connect the red wire of the 9V battery pack to one post of the foot switch
- connect the other solenoid wire to the other post of the foot switch
Step 8: You're in Business!
Make sure to check for leaks again, as this will be the first time water will be traveling from the solenoid valve to the faucet. Also, test both the hot and cold settings to make sure both solenoids are working properly.
Hope you find this useful!
Step 9: Version 2.0 and Beyond...
The first thing I did was install a push-on/push-off button into the pedal (wired it in parallel), so that I can convert the sink back to "regular" mode if we have guests using it. Fairly easy, and I'd recommend it.
However, I've also been messing around with everyone's favorite microprocessor, the Arduino, and have some cool modifications in mind. Once I get the solenoids wired up to some relays, it's a simple matter to have the Arduino take control of them. So then you could do something like replace the foot pedal with a proximity sensor, or replace the on/off button I mentioned above with a momentary switch that could set the sink to "regular" mode for five minutes when you press it.
Also, I was on the fence between getting a normally open or a normally closed solenoid valve. Having a normally closed valve allows me to keep the faucet handle "open" all the time, and I just have to step on the pedal to activate it. However, to return it to "regular" mode requires constant power. Since there are just two of us living here, and I'm using rechargeable batteries, I decided this was fine. It would be a simple modification to reverse the pedal and use normally open valves. This would allow the sink to operate in "normal" mode until a button was pressed, which would then activate the solenoids and close them, while stepping on the pedal would break the circuit and cause them to open, allowing the water to flow.
What other possibilities are there with a setup like this? Well, why don't you tell me!
Best of luck!