Bartendo

Bill:

I hooked up the load cell to the power supply and the multimeter to test whether it worked properly or not. I plan on further testing it by hooking it up to the load cell amplifier and using the multimeter to check the output and then connecting it to our Arduino to see if it can read from the amplifier.

Next week, I also would like to test out the larger but more inaccurate peristaltic pump. We would like to use this pump for our cleaning water supply as it will allow us to quickly dispense the water we need into the funnel. Also, next week, I would like to work on creating the funnel with the grate inside of it.

David:

This week I mainly set up the hardware and software parts related to the Raspberry Pi. I soldered the parts of the hats and also researched on drivers and installation related to the pumps and the valves. Moreover, I have started setting up the environment on the Pi.

Next week, we should be able to put the pumps and the Pi together and control them using the Pi. Thus, I plan to mainly do the coding related to setting this up and test using the Pi, and then we should be able to decide the design and put together onto the report.

Connor:

This week I tested out one of the peristaltic pumps. We pumped water from a container to a beaker. To pump approximately 70 mL of water, it took roughly 52 seconds to do so. We were able to do this without using a Raspberry Pi. To simplify things, we simply hooked up the peristaltic pump to a power supply in the lab (at 12V DC) and manually turned the power supply on and off.

Next week, I would like to have us come up with the basic scaffolding system for the pumps and bottles. This needs to be done as we need to submit our design review by next Sunday. In addition to that, we can begin building out our scaffolding design next week. I plan on going to the local Home Depot to pick up some items for scaffolding and tubing. In addition to this, I would like to test out the gravity-fed solenoid valve that we should be getting sometime this week.

Overall:

I believe that although we might be slightly behind schedule on some items, we are on track with others. Bill has begun testing out the load cell, and we have tested out some of the pumps that we will need for our design. While we were supposed to finish the design the scaffolding system this week, we feel very confident we can complete and begin implementing it by the end of this week.

The scaffolding design could change, but any deviations should be cheap and cause little to no delay in the schedule. We can most likely go to a local home improvement store to purchase any materials (PVC pipes, screws, etc.) with ease. While the scaffolding design is something we have to take some time to thoroughly think through, we have a bit more margin of error than with the electrical components due to price and accessibility. Also, by working on the design of the scaffolding this week, we can make online purchases if we are somehow not able to find such items at a local store. We also didn’t have any major changes happen to the design during the past week.

Bill: I looked more into how we could set up the load cell that we purchased. We would most likely be setting it up like the picture below.

However, we are considering putting a sort of basin underneath where the drink is getting dispensed, and putting a grating platform on top of the platform so that a glass can be placed on top of it. It would be very similar to the platform for a soda dispenser, like below.

This would be for collecting any drops, as well as the water used to clean the system between drinks. This complicates the load cell system, as the load cell needs to be able to sense whether a glass has been placed on the platform without getting wet. One solution is to put the 2 load cells on each side of the grates, like below.

This would require reading from 2 load cells at the same time, and coordinating and configuring the readings. The readings do not need to be too accurate, as this is just for sensing whether a glass has been placed or not.

 

For pumps, we ordered 2 pumps, a peristaltic pump and a regular submersible liquid pump. The peristaltic pump has to problem of possibly not being able to pump fast enough. The other pump is a lot stronger, and it has the issue of possibly being too strong and hard to control. Also, this pump has to be submerged in water, which is not ideal, whereas with peristaltic pumps we just need to put the tubes in the water and the actual motor stay out of water. We might be able to alter the pump rate by just altering the amount of voltage we feed into it. We will need to test these pumps out.

We looked into possible alternative pumps and found these:

https://www.robotdigg.com/product/686/12V-volume-flow-rate-dc-motor-or-stepper-peristaltic-pump?gclid=EAIaIQobChMIgI7ysPrY3QIVjFqGCh0ouwyXEAQYFCABEgI1tPD_BwE

https://www.robotdigg.com/product/1035/Stepper-motorized-openable-head-peristaltic-pump?gclid=EAIaIQobChMIgI7ysPrY3QIVjFqGCh0ouwyXEAQYBSABEgLhfPD_BwE

These are stronger, so they might work better for our project. However, there is no documentation available for these products. 

Next week, I will do testing on the load cell and the pumps. Ideally, we would test early in the week so we can quickly order any new pumps that will meet the requirements for our project.

David: Last week, we were settling down on the actual design of the entire system. We came up with two designs that we thought might work and would further do the testing to decide which design is better. The first design is to pump the liquid directly from the bottle, as the photo below. However, we had the problem of pumps not powerful enough and having to put the pumps inside the bottles, as Bill mentioned above.

Thus, our second design doesn’t use pumps anymore, but to control the flow with valves and gravity. (Graph below) However, almost all the valve we looked at require an at least 3 psi in order for the liquid to start flowing, which apparently we can’t achieve. Luckily, we found a valve online which claim to operate with little to no pressure at Adafruit. In this way, we would be able to control the amount of liquid and detecting liquid level more easily.

In our new design, we use two-way opening bottles so that we can simply add liquid into the bottles without changing to new ones and avoid the installation as well. In order to control the flow of liquid, we want to use a reservoir system, which includes a container and two valves. The valve above controls the liquid flow from the bottle. The bottom valve holds until we get the right amount of liquid within the container, which is detected by a liquid level sensor.

Even though the new system doesn’t require pumps to operate, we still need to test out the pumps, because there are liquids like syrup that might still require pumps in order to come out quick enough to meet our goal.

Thus, for next week, we need to test the flow rate and power of different kinds of pumps. Also, we need to test to make sure the new valve can operate in little to no pressure condition. Moreover, we need to test out different kinds of liquid level sensors. Based on the results of the tests, we should come up with a full design of the entire system.

Connor: Helped design the general structure of Bartendo with regards to the mixing station. I focused on how to mix the liquids from the various containers. The conclusion that we came to is to have the container hang from above. For us, this container would be a funnel, which will naturally drain out all of the mixed liquids that are in it. Also, there is also the product requirement where we need to mix the liquids once they have all been dispensed from their respective bottles. To do this, we will use a magnetic mixer stirrer that has a base that applies a magnetic force to a magnetic pill (which is in the drink) that will stir the drink. There is an issue though: the pill must be on a level surface and shouldn’t get stuck in the drainage hole in the funnel. Elsewise, the stirrer will not function properly. We can, however, avoid this by creating a filter that will lie at some level in the funnel, where the magnetic pill can sit and spin when the base platform applies the force. Also, with holes small enough, the filter will act as a grate, allowing the liquids to drain out of the funnel and preventing the magnetic pill from being caught in funnel’s drainage hole. We decided to create a “makeshift” filter by buying a plastic disk that will fit at some level in the filter and drilling tiny holes in it to both allow the liquid to drain at a fast enough pace and the magnetic pill to spin properly. To get a sense of what we had in mind, see the diagram below.

We still have to find a way to dam up the liquids to prevent them from pouring into a cup. After the liquids are poured into the funnel, there needs to be a way to keep them there. If not, they will simply be drained into the cup without being mixed. To prevent this from happening, we will use a gravity-fed valve at the bottom of the funnel which will be attached to silicone tubing that will lead to the cup.

Next week, I will need to order the magnetic mixer stirrer, funnel, plastic disks, and gravity feed valve. Once the stirrer gets in, we should double check to make sure that it will create a strong enough magnetic force even if the magnetic pill is not “sitting” on top of the base.

Overall:

Overall, there were a few changes to the design of Bartendo as was mentioned above for various reasons. However, I believe after this week, we should be down with most of the testing of our components. Because we should have our components by early next week, we should be able to begin and hopefully finish testing of said components. This will help us finalize the design of Bartendo. Even though there is some uncertainty with certain components, I think we have done a good job at minimizing the risk of things going wrong by thoroughly thinking of other designs that could serve as a contingency plan. Thus, here is the updated schedule:

 

 

 

 

For our project, we will be constructing an automated bartender system called Bartendo. It will contain bottles of various alcohols and syrups, and it will use different combinations of those to create an assortment of drinks. The user just needs to put in the order, and when they are in the front of the queue, they can place their glass underneath the dispenser, and the robot will automatically fill up the glass with the drink.

We will be using either pumps or valves to pour the drink into a central container, and use a flow rate sensor to measure and control the amount of liquid dispensed. There will be a magnetic stirrer plate underneath this container, which will mix the drink, and the mixture will be dispensed using either a pump or a valve into the glass. The platform for the glass will have a load sensor that will be able to detect whether a glass has been placed or not. All these sensors and parts will be controlled by a central Raspberry Pi. For interacting with the robot, we will create a web app that can be used to put in drink orders, check order progress, and check the status of the machine. The orders will be put into a queue, and the order in the front will be sent to the Raspberry Pi from the web app.

Our goal is to build a fully automated system that can create drinks within 30 seconds.

Welcome to Bartendo’s Project Page!

(Couldn’t figure out to put this into the header of the page so we decided to make it a post)

Bartendo is a project done by Team 3 for the Carnegie Mellon ECE Capstone, Fall 2018.

For Bartendo’s team, it is comprised of three CMU ECE students: Haocheng Dong, Bill Kim, and Connor Young.

• Bill:

I researched and purchased the load cell sensors and the load cell amplifier that will be used for detecting whether a cup is on the platform or not. Turns out the load cell cannot be used by itself, as the signal is too weak, and it is also in analog. We are purchasing a load cell amplifier that will amplify the signal, as well as convert the analog signal to a digital signal.

My plan for next week is to help design the scaffolding for Bartendo, and I will help purchase the parts necessary for the scaffolding. Also, I am currently on track with the work that needs to be done.

• David:

During the last week, I mainly helped research for liquid level sensors and load sensor. We as a team spent some time working on the proposal presentation. Besides helping the team, I did some research in PostgreSQL. I have had some experience with SQL previously, but haven’t used it in real application. Since I will be in charge of the database in later time of the schedule, I spent some free time this week to refresh my memory on using database systems.

My plan for next week would be to finish the design of scaffolding and determine the basic hardware requirements of the system as a team. Personally, I would like to start testing the pump for the flow rate of the different liquids, if we can actually decide what pump we would eventually use. Otherwise, I would like to start building some prototype of the scaffolding of the system.

In general, I am on track of the schedule.

• Connor:

This past week I worked on purchasing the Raspberry Pi’s and their accessories, such as micro SD cards and power cords. While I did do research on the pumps, we as a team wanted to a little more research before we ended up making a final purchase. We will send in our order for this upcoming Monday in hopes of receiving later the pumps later in the week and complete testing.

Here is one of pumps that we will end up buying:

Next week, I would like to have helped finish the design of the scaffolding for the product. I will also begin working with the Raspberry Pi to test the pumps to see if they are accurate enough for our use case. While next week will include both finally purchasing the pumps and testing, I am still on track with the schedule.

Overall, we did a good job at purchasing parts for our project and currently are on track with our schedule. Technically speaking, the only change that we have to make is to continue the task of “Order Pumps and Liquid Level Sensors for Testing” into this upcoming week. In general, we will have to focus on doing most of our research for parts ordering earlier in the week (Sunday through Tuesday) in order to be able to have our purchased parts shipped in later in the week.

One thing that we need to decide on is the physical positioning of the bottles. Will they be upright or inverted? This will determine the kind of components we need to extract the liquids from the bottles and the design of the scaffolding for the devices. This poses as the biggest risk that we have to date. However, we feel that we can manage this risk well because we are testing to see if the pumps are the best solution. If they are not, we will investigate other options, such as a valve system with the bottles being inverted.