Bill:
As you can see in the gif below, we ran an Arduino sketch that turned on the outlet for five seconds and then turned it off for a second and repeated this. Unfortunately, because we did not have the right-sized screwdriver, we had to manually hold the wires from the Arduino to the pins on the power relay.
For this upcoming week, I will be working on constructing the platform with the load sensor using the wood that we got from home depot. The first amplifier was giving me a lot of issues. When I tried measuring the output of the amplifier using a multimeter, it wasn’t reacting at all to the change in weight. We bought another amplifier and load cell, so I will try again with those. It I get those connected up properly, I will then connect them to the Arduino and see if I can get any readings. I already have the code for reading from the amplifier, so as long as I can get the load cell and the amplifier hooked up properly, we should be set. Afterwards, I will look more into having the Arduino communicate with the Raspberry Pi using a USB connection. If I manage to get any readings, I will move on with testing with glasses of different weights to see how to calibrate the cell to be able to detect glasses of various weight.
Connor:
During this past week, I was able to work on beginning to assemble the scaffolding. This involved cutting some of our PVC pipes to the exact lengths that we have specified in our design with a machine saw that we found in the machine shop in Hammerschlag. While I was able to make a few cuts with the PVC pipes that we had bought last weekend, we, unfortunately, did receive the joints that we needed to connect the parts yet. Also, the machine shop was closed this weekend as we needed to cut more PVC pipes that we had bought this weekend. With regards to the valve that we are using for the mixing station, we realized, with the help of our TA, that we didn’t have the power supply necessary to operate the valve. With that said, we ordered a power supply, 12V/5A, to operate the valve. Also, I also did some testing with the magnetic stirrer. We hooked it up to our AC/DC power relay, and it seemed to work as designed. However, we have thought about our design recently and thought that there might be an easier way to handle mixing. Instead of having the funnel hover above the mixer, it might make more sense to have some kind of cup titled a bit sideways and then have the magnet and motor that was apart of the magnetic stirrer mixer attached directly to the bottom of the cup. We would then no longer have the potential issue of the funnel being too far away from the magnetic stirrer mixer to mix the drink. To drain the liquid into the cup, we would make a hole in the cup, caulk an adapter to the cup which will attach to some silicone tubing. I also changed some of the dimensions of the scaffolding such that each bottle resides in an 8” by 8” square of tubing, instead of the original 6” by 6” that we described in our last weekly report.
For this upcoming week, I plan to cut the rest of the PVC piping, since the machine shop is open during weekdays. We should also receive our PVC joints sometime early in the week. With that said, my goal is to finish assembly of the scaffolding (the PVC piping). In addition, I will begin working on finishing the details of our design and the begin the implementation of the new mixing station. We will test some possible ways to keep the beaker slightly tilted (possibly chicken wire).
David:
This week I ordered the three power supplies that we need for our design. We are currently using the power supplies in the lab to provide power for the motor hats, but they don’t quite meet the power requirements for the hat if we are driving four pumps simultaneously. Moreover, we won’t be able to test the bigger pump we had for rinsing system because it requires even more power than the hat. I tested out controlling the pumps to turn on and off for a certain number of seconds. We also tested out controlling the power relay using Arduino, which would turn the mixer on and off, as you can see in the gif below. I was also able to connect the Raspberry Pi with the Arduino and control the Arduino using RPi.
With regards to the rinsing system, since we don’t have the power supply or the pumps yet, we won’t be able to quite test them and make decisions on the design. However, it should have the same mechanism as pumping other kinds of liquid (with or without the stirring part).
We were able to take the stirrer apart and show that the stirrer still works in our new design as Connor mentioned above. The gif below shows how it would work in our design.
For next week, I need to finish testing the pumps and power supplies and decide whether we can use the big pump for rinsing water or not. Also, I should try to figure out how to drill a hole at the bottom of the beaker and find a matching adapter for the hole and the valve.
Overall:
We have made some progress this week in regards to the design of the subsystems. We did make some design changes, which will not increase our total amount by a lot, as well as the mixing station, which has been described above. However, we believe we can finish working on the scaffolding early in the week, which will allow us to begin implementing our mixing station design and provide a nice foundation and visual for the mid-semester demo. While we believe that the new mixing station design will use chicken wire to stabilize the cup and won’t cost a lot of money, we need to begin the implementation process. If we run into issues with the PVC piping, then we can still build the system without a foundation. It will just be more of a hassle, and we may have trouble later on with trying to build a foundation after connecting the inner system. If the PVC piping for some reasons does not work, we also have access to wood in the cages area. While it will be harder to build, and possible less stable, it should be sufficient for our device.
In the following weeks, we are going to try and get the Raspberry Pi to completely control a single pump, as well as the mixer to see if we can get the system working with just a single bottle. We believe that as long as we can get it working with a single bottle, it should not be too much trouble to expand to multiple bottles. The possible problems are with the power and the motor hat, since we will have to power more devices.
