The main body of the pole attachment has been done for some time, but getting the wires of the strain gauge through the tube was the lasting thing remaining. The main trouble was that the wires would only go through a section of the guiding tube and then get stuck. They now go through all the way very smoothly. 

The first iteration had a right angle that impeded the passage of the wires. It would only get through the hole but not through the corner. The logical next step was to reduce the amount of curvature that the wires had to go through. To work around this problem, I inserted a piece of wire through the top hole and soldered all the tips of the wires from the strain gauge together. I then pull the wire, and since all the wires were soldered to it, they all came through. This worked well but is not ideal. This is why further development was needed. 

The final design was different than what I was initially thinking about. There is no curve to the side instead there is loft coming from the side of the block in the form of a rectangle to a circle. This design makes it so that the wires don’t have to go through corners.  

This is the iteration that will be used for testing in Kenya. Here is an interactive model of the piece:

The system has been printed. There are so minor flaws with will be addressed, but we have our first prototype. 

In the image above we can see both of pieces that are 3D printed. The pole attachment is locked to a piece of aluminum extrusion just for demonstration purposes; it also has a battery sitting on it to keep it from falling. Our validator has a 6mm hole diameter siphon and will drain all the container in about 50-55 seconds. An ADC will be amplifying the signal coming from the strain gauge and outputting data to an Arduino UNO. All the electronics will be located on top of the pole attachment.

The flaws that were previously mentioned were about the attachment. The holes for the u-bolt are a little bit too close so I had to drill them out to get the u-bolt to fit. Another thing that will be changed is the little tube on the side that guides the wires coming from the strain gauge. It has a 90-degree corner that makes it difficult to pass wires through it, so I will modify the design to make it smoother. Other than that, our desing is complete. 

After many tests to figure out what would work out the best, we have chosen our best design. We will be using a 6mm diameter hole for the siphon, this will be sufficient for what we need it to do. I have been able to put together a model of the whole system to be able to visualize the prototype. Here is a rendering of the Super Validator configuration: 

This model only has the parts that will be 3D printed, the electronics will be sitting on the part that is attached to the pole. The electronics consist of a strain gauge connected to an ADC that will be sending data to an arduino.

The electronics have been calibrated and tested. We are currently printing both the validator and the pole attachement, and will soon have the first working prototype. 

After running the test we were able to conclude that the 8mm diameter hole is too big to create the siphon at the slowest rate on the OPEnS Calibrator. 6mm diameter hole works just fine but takes a little more time than what we want it to. We are going to try a 7mm diameter hole and see how it performs. If this does not work, we will move to other designs. Here are links to the other designs we will try:

http://makezine.com/projects/make-35/ctesibius-and-the-tantalus-cup/

We have created three working prototypes of the validator. The main difference between each of these is the diameter of the hole that siphons the water out. We are currently working with 4mm, 6mm, and 8mm diameter holes.

We wanted to drain the validator in about 30 secs, if possible. We started by printing a 4mm diameter hole for the siphon but that turned out to be insufficient. We went on to make a 6mm diameter hole and it performed better but not quite as we wanted it to. After that iteration, we made an 8mm diameter and it worked great, with such wide orifice came a drawback.

To test the performance of each of the validators we used the OPEnS Calibrator; it was set to the lowest setting which is the 30 min setting. I initially filled the each validator with 500ml of water and then added more water to reach a height of about 1cm below the siphon’s top. The calibrator was then placed on an o-ring stand above the validator and left to filled the validator the rest of way. 

The rest of this post will discuss each of the validators performance and show the videos of the trials. 

The 4mm diameter has troubles creating the siphon but after it is established it works just fine. For some reason, the siphon is not created and we need to push the water into the hole to get it started. This validator takes about 2mins and 20 secs to drain itself. 

The 6mm diameter validator works just fine. The only thing that restricts the flow of water is the mesh that it has at the inlet and outlet of water, created to keep bugs away. With both meshes, it drains in 1min 35sec. With only the inside mesh, it drains in 1min 18sec. Having no mesh at all lets it drain in about 50sec. This version can create the siphon effect at the rate the water is coming down from the OPEnS Calibrator.  

The 8mm diameter validator drains the fastest; it will drain in about 20-25 sec. The only problem with this is that the water flow coming into the validator has to be really high otherwise, the siphon can not be established. The flow of water coming down from the OPEnS calibrator is not enough to commence the siphon effect, so the water only really trickles out of the validator.