Automatic bar tender : Body frame and electrical building parts

Hey guys, my name is Jérémie and today I ‘am going to speak you about the hardware of our bar tender project. In this video I ‘am going to details how we have made to design all the machine and what material we have used to convert our ideas into a real and functional device.

In this first post, my job is to speak about the mechanical part of the machine then how building the device. The major idea for this project was to only use or to use a maximum of recovered material. Firstly, because we are students and we have limited budget and also to make sure that everyone is able to reproduce our bar tender.

Then we can start with the first step that is to build the body frame of the machine. For this, we have used recovered wooden board from an attic. All the board are shaped into rectangle and joined together with several screws. The size of the structure has been decided by placing 5 bottles aligned and checking the overall length.

When the body frame was fixed to make one piece, we have cut a piece of rigid cardboard and fixed it behind the structure. After we have placed a wood board in front to block the bottles and make sure that it is not possible for the them to go out of the structure.

Once this job has been carried out, it is time to add some wood boards to realize the axle support for the conveyor. They are ready to be perforated and to incorporate the shaft to allow the conveyor to work properly. Moreover, a little piece placed on the top of the body frame is added to create a fixation point for all the piping providing the drink. This component will be detailed forward in the video.

To come back on the shaft support, they are made by inserting à steel pipe surrounded by a PVC one. The diameter of the PVC pipe is slightly wider than the other. That make it free to rotate around the steel pipe. The rotation is possible thanks to the glide between the steel and the PVC.

The next step was to think about the stabilisation of the glass on the conveyor. Then we have carefully cut a thin wood board with a jigsaw and fixed it in the front of the structure. In this case, the conveyor rotates around the axis support and can slide on the wood support to bring stability to the filled glass.

Before inserting the electric motor for the conveyor on the structure, we have took a  MDF plate that is the base of the machine. Thanks to this, we can place the machine wherever we want. Moreover, the structure is reinforced by its fixation on the plate.

After this, the bar tender is ready to be paint, once again, we have chosen a recovered material. That’s why the structure is paint in black.

The final step was to insert auxiliary components on the structure as the pumps, the piping, and all the electronics that command all the operations.

At first, we have perforated the board on the top of the structure and fixed a threaded rod on it. The rod extremity height corresponds at the top of the glass where the liquids are poured. An annular wood board is fixed on this extremity, and 5 holes are perforated where are inserted each pipe. They come from a bottle, go through the pump and finally go out of the pump by a pipe that is inserted in the annular wood board that I was speaking about previously.

We have chosen not to make the piping visible. Then we have put a hold cable duct to insert all the pipes. These pipes are traditional plastic pipes used for all domestic hydraulic applications.

That’s all for the body frame building part. Il leave you with Benoit who will explain the electrical building part. Thanks’ for watching, see you next time!


Hello everyone,

I’m Benoit of the cocktail Team! In this last video, I’m going to explain the electrical building part of our cocktail dispenser.

First, I’m going to make a brief reminder about the listing of the main electrical material needed to make our project functional:

In this project, we have bought 5 centrifugal pumps destinated to an aquarophilia use. Each one is powered in 12DCV and with this voltage, it can reach a flow rate of 240 l/min.

We have also bought 5 Arduino relays, one Genino Arduino (a uno can be adequate for the application). In this project, we have used this object as a slave interface to command all pumps.

Finally, we have used a raspberry PI 3. This device is the most important object in this project because its broadcom chip allows to connect it on a local or online network, furthermore, it allows to manipulate a database because it has a bigger memory than the Arduino. So, it is the brain of our project!

We have bought the pumps on amazon for 5€ each. We have chosen these even though they are really not optimised to this application, because they are low-cost pumps and their flow rate allows to fill the cocktail glass really fast.

We have cut the base connector of each pump and soldered each wire to an Arduino connector. In this way, it’s easier for us to plug these devices on a breadboard.

In the same way, we have cut the connector of an old 12VDc power supply of 500mA and soldered 2 arduino connectors.

Here are the different connections:

First, to power and send the program to the arduino and the raspberry, we have connected these on a laptop by USB.

Then, the arduino connections are pretty basic:

We plug it to a 5VDC sector power supply. As the Arduino is the main device which helps to command the pumps, we must connect each pump on it. However, the power supply voltage of the Arduino and the pumps are different which means that we must pay attention to insulate both supplies between them. Otherwise, we risk to create a short-circuit and to burn all electronic elements. Moreover, we can’t power the pumps with the 5 VDC Arduino supply because it is too low to operate the pumps.

Therefore, we used arduino relays because they create a « galvanic » insulation between the supplies.

As a reminder, a relay is a kind of switch which allows to command an electrical circuit. This switch is operated by a magnetic field which is generated by a self. The self is powered by a secondary circuit which is generally of a lowest voltage than the first one. There isn’t any contact between both circuits and it is that what we called a galvanic insulation.

This is the interest of this device, because we can command a 12VDC circuit by a 5DCV circuit without any risk of short circuit.

The relays have 3 connection pins (VVC – Ground – In) of command circuit by side and 3 others (NO-NC-ground) of power circuit by side. We must plug the Arduino 5VCC on the “VCC” pin and make the same for the ground. The “In” pin must be plugged on an Arduino digital output. The first pins allow to power the relays whereas the last one allows to operate the self.

We have plugged the pumps on the connection “Ground” and “NC”. The plugin is justified because our program activates all pumps at the startup.

To ease the connections, we have used a breadboard to gather all indirect plugins.

So we have connected the power supplies on the track  + and – .

We have finally made the connections like on this schematic (it is not contractual but it’s the main principle):

Capture d_écran 2017-05-22 à 12.43.18

I hope you have now the whole information to make your own cocktail dispenser.

See you soon!

Automatic bartender (post 3) : software librairies

In computer science, a library is a collection of non-volatile resources (which is a type of computer memory) used by computer programs, often to develop software. These may include configuration data, documentation, help data, message templates, pre-written code and subroutines, classes, values or type specifications.
Library code is organized in such a way that it can be used by multiple programs that have no connection to each other, while code that is part of a program is organized to be used only within that one program.
This way to organize a library is really interesting to reuse it whenever you want in a program or in another one.
Moreover, it helps the “junior” programmer to begin or to develop his own code with a reliable piece of code.
So I will describe you which library were used, where it comes from and why it is useful in our project:
Let’s begin with the libraries coming from Arduino and the Serial one, this library is used to communicate between the Arduino and other components. We are using it to communicate with the raspberry pi. Serial:
Then, the LCD is chosen because, like its name said, a LCD screen is used to display the different choices and the preparation state of the cocktail. LCD:
The SD library is useful in our project because it stores a file in an SD card and we need a TXT file to store all the volume data. SD:
A 2 wires sensor is used in the project so the SPI library is interesting. Actually, this library will probably be used because we need a goblet position sensor and a goblet filling one. In function of the components finally used, we will appeal the SPI. SPI:

To go on with libraries used in the raspberry pi let’s talk about Python which is not really a library but more the language used to navigate in files and allows to use some controls. This is essential to acquire data from the TXT file.
Then to be able to communicate by Wi-Fi between android and python, the socket library is used.
One of the last one is the Xamarin Studio library, already installed in the android interface. This allows to include different packages in the app.
And finally, we need a library to communicate from a smartphone to the raspberry pi via Python.
These libraries are downloaded from the same website : . Actually, they are already installed in the program, so it comes from the program download link.

Automatic bartender post 2 : project presentation & material


Our project is about automation of cocktails mixing. We would like to create a machine able to make some cocktails from a display.

First, a cocktail receipt stored in a database is suggested to the customer (2 or 3 receipts).

The project is composed of 5 bottles of (fake) cocktails or alcohols and every bottle is derived by a hose to the glass position (nozzle).

A glass is placed under the nozzle of bottles. A proximity sensor allows to the machine to detect the presence of the glass and to make the cocktail.

The device used to drive the liquid from the bottles to the glass is a peristaltic pump. After a long discussion between each members of the group and some tests, this is the best solution we keep thanks to its ease to instal and its low price. In fact, the process just need a dip-tube in the bottles passing through the pump and ending in the glass. The project need a tiny volume for each glass and a tiny flow is possible with this kind of pump so that’s why it’s the best solution. Moreover, in comparison to another pump or an electronic batcher, this costs something like 15€ which is really cheap.
If we have enough time, we could program the possibility of ordering a list of cocktail by the user to accelerate the process. So, 1 easy selection of different cocktails and the machine takes care of everything. Cheers!

We have also determine a last solution, cheapest but that allows to make a maquet aspect.

We would like to recycle an alcohol bar dispenser. This object allow to distribute an exact volume of alcohol to make a cocktail. The system is composed by a little bucket of 5ml and a cross shaped piece which is positioned at the termination of the bucket. When the cross is pushed the bottle neck is filled in and the volume is evacuated of its liquid. the inverse is done when the cross is relaxed.

We would like use and motorise the system. We can use a motor which the motor axe is connected to a radial lever. We control the rotation of the motor to push on the cross.

Then, the system is the same of the other solution. Each bottle is connected to a hose which to redirect the fluid to the nozzle.


Capture d_écran 2017-03-18 à 22.51.26

See you soon !

Automatic bartender : Team and project presentation

Hello followers, we’re the CocktailTeam and we’re going to present you our electronic and electrotechnical project above the next three months. At first, in this post,  we’re going to introduce each member of the team, with his motivations.


Our team is made up of six members, future electromechanical engineers with different specialisations. So, each member is currently a fifth-year student in a programme leading to a master’s degree in industrial engineering, at the HELHa college (Haute Ecole Louvain en Hainaut) in Mons, Belgium.


This project proposes several purposes. Indeed, it’s interesting in order to better prepare students for teamwork. Furthermore, the fact that it is developed in English should improve our English skills. Lastly, various assets of each member will allow us to carry out a successful project from conception to completion. The aim is to link signals and power.


Half of the team is made up of people specialised in thermal process, and the other half of people specialised in automation.


Justin OVAERE, 22 years old is specialised in thermal process. He is also well interested in programming. He hopes you will enjoy the project that we’re going to develop together.


Benoît BAILLY has always been interested in the conception of many things.

Child, he would be an inventor.

According to his child‘s dream, he has chosen to study in Electromechanics since his secondary school (equivalent of Middle and High school) especially in the industrial automatic (at the university).

He’s totally fascinated by the automatic machines and robots. It’s a very interesting thing about an interesting domain.

In a few couple of months, he will be graduated in industrial engineering. It allows him to realise “his kid‘s dream”.

Versatility, dynamic, meticulous are some words which describe him.

He hopes to bring his skills and knowledge to conduct the project.


Axel PATTYN, is specialized in Electromechanics and Thermal engineering. He’s really glad to be part of this project which is developed in English because he gives importance to this skill since he performed an internship in America.


Florent MARTELEUR likes computer programming and it’s for this reason that, after his Bachelor’s degree in automation, he has continued his studies to make this Master’s degree, with the automation specialization.

This project is an opportunity for him to improve his English and his programming skills. And so he is very excited to begin to work for this one.


Jérémie FEDERICO is the third student of the team with thermic specialisation. He already has (owns) a bachelor’s degree in automotive engineering, that’s the reason why he is fluent in the practical aspect of a work. He has decided to go further by studying this Master’s degree and be involved in industrial projects in the future. His interest is about the real application that consist in this project. He will improve his groupwork skills and his English level.


The sixth and final student is Baptiste FEDERICO, 25 years old, also automation specialization. He’s more theoretical than practical. This project is very exciting for him because it could bring him more resourcefulness he needs it ! The fact that this project is developed in English is also useful for our future. The use of new materials, like Arduino and Raspberry Pi, is a good challenge for the team.


Now you’ve met the team, you are ready to see our first video post !



As you can see, we are going to build an interesting project, please stay focus on our progress. For the people concerned, a second post is coming soon about the project presentation, about what we’re going to work on.


See you soon.
The CoktailTeam.