Finalized Pole Attachment for Super Validator

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. 

 First design with 90 degree corner First design with 90 degree corner

 First design with 90 degree corner

Second iteration with a smoother pathSecond iteration with a smoother path

Second iteration with a smoother path

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.  

Final design of wire guideFinal design of wire guide

Final design of wire guide

Cross section of wire guideCross section of wire guide

Cross section of wire guide

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

Polev52 By Manuel Lopez Modelo »

Printed Super Calibrator System

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

3D printed Validator and pole attachment 3D printed Validator and pole attachment 

3D printed Validator and pole attachment 

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. 

Super Validator Model and Electronics

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: 

Super Validator systemSuper Validator system

Super Validator system

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.

Electronics setupElectronics setup

Electronics setup

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. 

Super Validator 7mm

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:

We will replicate design B. Designs  A & C  are similar to what we have already. We will replicate design B. Designs  A & C  are similar to what we have already. 

We will replicate design B. Designs  A & C  are similar to what we have already.



Super Validator Testing

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. 

Pythagorean Rain Validator

The rain validator needs to be drained after it reaches its maximum capacity. To do this we implemented the Pythagorean Cup principal. This allows for our validator to reach a certain liquid capacity and then drain. The principal is quite simple; the liquid is permitted to rise to a certain level and when the point is reached, a siphon will drain will the container. 


Rain Validator CAD rendering 

Section Analysis of the Rain Validator using Fusion360

Our design works but needs modifications to be able to work appropriately. The following video is a demonstration of the current desing. 

New Laser Cutter Lens

The laser cutter came with another lens that we were totally unaware of its existence. Why would such expensive machine be missing one of its main parts? Looking through an accessories box of the laser cutter, I came across a little box that contained something wrapped in white paper- it was the other lens! The lens that we were using would only cut when it was in the metal-cutting position, even though we were not cutting metals. This new lens can cut in the non-metal and metal positions. 

New lens 

The very first thing that I tested  was if it could cut in the non-metal-cutting position. After that, I proceeded to test cardboard, plexiglass, and foam.When cutting foam we were getting beveled cuts. This was the main reason we considered buying to new lens to get better cuts. 

 Circle and rectangle test cuts with new lens. Of each set, the left pieces were cut with the old lens and right pieces with new     lens.

We can observe that the new lens can cut straight down the foam without creating a bevel. This is exactly the type of quality we need and expected from such a laser cutter. With our old lens it was really hard trying to get a straight cut; we got pretty close but nothing compared to this new lens.

Rube Goldberg Project Box

Making this box is not as simple as I initially thought. One of the most time-consuming parts of this box is making the finger joints. After making the finger joints the rest of the process was very smooth. 

CAD rendering of the box in acrylicCAD rendering of the box in acrylic

CAD rendering of the box in acrylic

Finger joint designFinger joint design

Finger joint design

The CAD was the first thing that was done and then DXF files were exported to the laser cutter. The first prototype of the box was made out of cardboard to make sure all of the sides would fit perfectly- not too wiggly and not too tight. 

The DXF files are the surfaces sketches of each of the faces of the box. These files are the ones that are processed into the commands that the laser cutter uses to position the laser. Having the CAD finished makes it easy to produce these files because we just pull them off the faces of our designs. 


Cardboard prototype 

We also did our first tests etching on cardboard. The OPEnS logo was the design that we used for our testing and it came out very well. 

First cardboard etching test 

V84 of Soil Vapor Sampler

A few changes have been done to the Soil Vapor Sampler. The design has been flip upside down. This was done to accommodate the new cap. The angle at which the tubing came into the sampler was also modified. The hole is now directly extruded towards the center, this facilitates the insertion of the tubing. 

 New Vapor Sampler Cap    New Vapor Sampler Cap   

 New Vapor Sampler Cap


This new cap goes on the bottom soil sampler. This is the piece that gets inserted into the ground first. 

Cross section of vapor samplerCross section of vapor sampler

Cross section of vapor sampler

The gray long tubes are the pathways where the tubing goes through. With the direct path, the tubes have no troubles going in. 

This is the model of a vapor sampler with all the pieces put together. The white piece is the microporous tubing that would go between every sampler and between the last sampler and the cap. 

Making Photo Booth for OPEnS Lab Projects

At the OPEnS lab we prototype many projects and need to document them. Pictures are essential to our reports and publications. In order to have the best quality pictures we decided to make a photo booth. Here is the CAD of our booth. 

First version of CAD

This photo booth is a light box, a tool to take professional looking photos. Our is a  DIY version of the ones we could buy. The idea is to have all of the openings covered with tissue paper and a light source on each side of the box. The paper will serve as a filter, giving the object inside an even lighting. Here is an example:

To take the CAD into the laser cutter I converted separate sides of the box into DXF files. These files are then processed by the laser cutter software and then loaded to the laser cutter. Here is what our photo booth looks like so far:

Some materials are still needed but it is almost done.