Solenoid Cutter Mechanism Video

Solenoid Cutter Mechanism

Since I have my solenoids working properly I started working on the cutter mechanism. Solenoids are really neat mechanisms and if it weren't for them generating A LOT of heat I wouldn't even have to design a mechanism. But they do, so I will!

The purpose of this mechanism is to allow me to keep the cutter open or closed for ANY amount of time. I started thinking of all these neat mechanisms that would allow me to latch the solenoid. These were pretty complex but eventually it got more and more simple. Eventually it came down to this design.

The figure below show the solenoids in the starting position. You can see that the solenoid plungers don't have any magnets attached to them or anything. The magnets are on the brackets at the end. The solenoid at the top is in the on postion, meaning the current is running through it to attract the plunger and retract it. The bottom solenoid is in the off position. I don't have a representation of a hole in this experiment but imagine that the hole is just to the right of the bracket in the middle.

In order to cutter the water the bottom solenoid will turn on, but just for a moment (200 ms). Once the cutter mechanism has moved to the "closed position" (see figure below) the upper solenoid engages the magnets and the valve is now closed and all current is off.


In order to move the cutter mechanism basck to the start the top solenoid is turned on and the entire process starts over again.

I can't say that this is the exact design that I am going to use yet. I still have a few other ideas that I have before I commit to one design, but so far I am pleased with these results. So I only run current through it to move the mechanism once it arrives at its destination the current turns off and remains in the position until the next solenoid is turned on. That means no excess heat, and remember HEAT is the enemy in electronics.

Coolest service ever!

I realized that the design for the Laminar Flow Nozzle is starting to get a little complex, and by complex I mean things that I can’t manufacture with my little drill press. However, if you need a small hole drilled into something I'm your guy! My previous experiences with manufacturing companies went well. I just called them up, emailed them some documents. They gave me a quote and we went on our way. I never did much shopping around since I only knew a handful of companies.

I was headed down that road again. I emailed 2 companies that I knew could make the part that I needed, but days went by and they never emailed me back. A long time ago a friend of mine told me about this great website MFG.COM. Essentially is an eBay of sort but for manufactures who want jobs. So people and companies submit an idea/documents for something to be manufactured. The manufacturing companies look at the design and submit a bid to make your desired product. I guess it’s more like a silent auction.

So I signed up! It was really easy to sign up and submit a RFQ (Request for Quote). The next morning I looked at my RFQ and there were 20 bids for my parts. They ranged from $4 to $256 for a quantity of 8. WOW! The lowest bids came from over shores. I’m not sure I want to venture out that far just yet so I’m going to go with a company in California.

So they are going to make my parts for me. I will have them in a little over a month.

Solenoid Tests

I won’t detail the setup exactly in this post, but I just received my solenoids from Goldmine Electronics and they are awesome. Thanks to Zachary for pointing me in the right direction on that one. I’ve never played around with solenoids, and they are very basic, but what can you expect when you only pay $0.99 for each solenoid. How do solenoids work? Well, when you run current through a wire you get a magnet field. This magnetic field circles around the wire. When you wrap the wire in a coil you get a stronger magnetic field! Wrap it enough times and run enough current through it you can get a large enough field to attract an iron core plunger. When the current turns on the plunger is attracted and retracts. When the current turns off a spring returns the plunger back to its original position. That’s the basics of a solenoid.

Drawbacks:

Solenoids need a large current to run through it in order to create a large enough magnetic field. Since nothing is a 100% efficient you get a lot of HEAT. Heat is the enemy in electronics. If things get too hot things burn up and solenoids are no exception. So you can only run them for about 25% of the time and they have to rest for 75%. That is going to make it difficult for the cutter mechanism. Since I want to be able to keep everything open or cut the water at ANY given time, I will have to think of a clever mechanism that will hold the cutter in its proper place one the solenoid have moved it to its desired position.