Day 4: #WorstWednesday

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The Auger screw for flour dispensing

We finally got our hands on the ~9hour 3D print of our own CAD-design of the auger screw. We got some valuable insights from the moments we had to remove the supports for the structure. Getting the auger screw free from the support was messy – and the rotor pin broke off in the progress. Thus we spend some time drilling a hole through the center, and replacing the PLA pin with a metal pin. This is going to be redesigned in the upcoming version of the auger screw.

The 3D printed auger screw, on a laser cut gear, after the initial prototyping session.

Don’t say it with flour

Flour is filled with counterintuitive properties – not entirely easy to dispense precisely. Our first prototype with the small auger screw seemed to let the flour out fine from the bottom. But due to the amazing properties of flour, we would be restricted to a canister with the same diameter as the auger screw, if we were to rely on gravity itself. That would cause the flour-canister to become tremendously tall and slim, which is not quite suitable for the user, when flour is poured up. Therefore we needed a larger auger screw – or another way of dispensing the flour.

One of the issues with our current model of the flour-dispensing mechanism, is that the flour is falling straight down on the stepper motor. We have looked into different kind of bevel gears that would solve this issue by providing an alternative placement of the motor. In the morning we woke up to a team member having provided an alternative to expensive bevel gears, which was fast and easy to prototype on. We laser cut the parts needed, and tried to do a test of the gears and the new auger screw in the flour canister.

The Auger Screw v1.1 failed us

The flour went through the first to slopes seemingly without too much difficulty, however it came to a stop, no matter how many turns we gave it. At one point the flour began spinning on top of the screw, so no flour could be added. We learned that we should implement a wall on the flour canister to ensure it would not follow the spin of the auger screw.

Prototyping on the auger screw with the gear mounted on it. (Look at the empty space in the canister)

The test gave us following insights:
We need a higher slope and/or fewer threads, which should be included in the next version of the auger screw.
OR we should look back at earlier ideas of dispensing flour.

  • By removing some of the threads on the auger screw 1.0 we got new insights and transformed the model to a auger screw v1.2

Alternative flour dispensing mechanisms

The “classic” or corporate way of dispensing flour, is with flour falling down on an auger screw, which moves sideways. We did a quick test with a flour canister, and it was too narrow to provide a proper slope for the flour to fall. Therefore we try to improve the current auger screw model, while we think of super smart alternatives.

Higher slope & fewer threads for Auger Screw v2.0

We set the new model up for 3D print, and will wait excitedly till tomorrow. The new model will have room for a metal rod to be inserted as a core – to give it the strength needed to dispense the flour.

Container lids

We worked on the lid for the flour container and the water container. The lids need to have holes for the ultrasonic sensor, the sensor is needed to measure how much flour and water is left in the containers. The lids need to hide away the cables and the ultrasonic sensor. We laser cut a part of the lid to see if it fitted the container and that the ultrasonic sensor fitted in the holes. We disused if the lid should be a cylinder, or a cylinder with a sloped top surface. We also played around with a design where the lid had a cylinder shape handle that will hide sensor. For now, we choose the cylinder shape lid. The lid will be made of 2 laser cut acrylic plate with holes for the ultrasonic sensor, a cylinder with holes for the cables and waterpipe and a top plate also made out of acrylic. We made drawing of the lid parts, so that we are ready to laser cut the parts. Because the acrylic is clear we need to paint, so that the sensor will not be visible. We consider, making the lid out of wood, but if we use wood, there is a chance it will reshape or rotten, with contact with water. It is also important that the ultrasonic sensor we stay clear of the water to avoid short circuit.

The mixer motor

So, we have had quite a few struggles with how the motor is going to work together with the dough hooks. The problem is, that the dough hooks should be in a neutral position when they haven’t been turned, and we don’t know if this can be done with a stepper motor without extra logic. A servo would be more suited as it has a rotary encoder to keep track of the position.

After some discussions we decided to mechanically force the dough hooks into a neutral position every time. This is done with a guiding channel where the dough hook axle can only pass through one way, any other way will turn the axle into the correct position.

Day 3: Tuesday – Water pump and containers

emiliekjeldsenLeave a comment

On tuesday we mainly worked with getting the water pump to work, prototyping a new type of mixing blade and a new bigger auger screw and deciding the size and shape of the flour and water containers. We also begun making the overall structure of the NodeRED flow.

Water pump

We made the water pump work by finding a suitable Arduino code and connecting a diode and a transistor to the system. The Arduino was run by the computer and the water pump was run by the power outlet (12v adapter). The pump is fairly small, but can still transfer 1 dl of water in a time span of 2 minutes, which fits our needs just fine.

Testing the water pump

The prototypes of the new mixing blade and new auger screw were initiated, which we will work further on tomorrow (see separate blog post).

We also cut some acrylic cylinders to use as flour and water containers.

Flour and water containers

We also made questionnaires to cover the users needs and habits when it comes to their sourdough, which we posted in various facebook groups. From this we hope to know more about the way the user interacts with their sourdough and what they need.

Day 3: Tuesday – The sourdough mixing chamber

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Today has been focusing around detailing the essential parts for the MVP.
Designing the concept and detailing the geometry requirements has been the one of the tasks for Aksel, Ruben and Sebastian this Tuesday

The mixing chamber has a lot of requirements and is one of the essential parts of the apparatus. This is the most frequently used part of the machine, thus it has to afford easy use.

The rough concept for the sourdough container / mixing chamber

The vision: the user can at any point easily pull out the chamber and pour out the desired amount of sourdough and place it back. The entire thing is easy to wash and easy to know dose and keep the minimum amount of dough in the container. †

The mixing is done by turning the dough hook axle between -45 to 45 degrees, and potentially higher as the dough increases in size, thereby saving energy whilst mixing the entire dough.

The dough mixer

The shaft easily snaps into the container and can only face one way; it can however sit whatever way in the container. We chose this as it allows the user to have the handle in whichever side that fits their kitchen, whilst only being insertable that way.

As the dough hook is always in the container, thus making it easy to clean the entire container; even though it’s hopefully an uncommon event.

If the user wishes to mix the sourdough further then they are able to by turning the dough hook axle with their hands.

When removing dough there are several options depending on the dough consistency. If the dough is very liquid, then it can be poured using the containers designated pouring tip.

If the dough has gotten a high viscousity it can be desirable to use a spoon or whatever other tool. In this case can snap it out the axle and lay it in the creaveses on the left side of container, whilst keeping the hooks submerged. This avoids spillage when removing dough and even keeps them in whilst pouring.

The sourdough container

The container will consists of a somewhat halfcircle with a round foot, a pouring tip in the one side, snap fit ‘bearings’ for the dough mixer and a handle. On both sides are there measurements, displaying a minimum amount of sour dough to keep and mL/dL. The round foot is also used for guiding the container using a simple channel system. This is to ensure a smooth connection between the dough mixing axle and the motor.

The exact geometry of the dough hooks is yet to be determined, we have had one prototype was not suitable for high viscosity doughs, it wasn’t too pretty either. Therefore have Aksel and Ruben created a prototype which will be tested tomorrow hopefully with the stepper motor. Early tests were conducted turning the dough mixer manually, which is not as representative of the real world as is desirable. This stage might be pushed later into the project as it is easier to optimize when the MVP is done.

Day 2: Friday – The auger screw and mixing chamber

helenewaldmannLeave a comment

One of the things we believe to be most challenging about the mechanics of the sourdough machine, is dispensing the flour. Flour is generally hard to pour evenly, for example when pouring it from the bag to a bowl. It tends to stick together when tilting the bag, before it suddenly slips and too much flour falls into the bowl. Therefore, we needed to make a prototype to test if it would be beneficial to dispense the flour by moving it with an auger screw which we 3D printed. We tried moving it upwards, sideway and downwards and learned that moving it upwards is possible, but very hard. Therefore we figured that this would not be the most efficient way to transport the flour. Moving it sideways, however, is possible and works quite well.

  • Testing the auger screw sideways
  • The auger screw is inside the pipe

The problem with moving it sideways and downwards was that not all the flour would fall down and get fed into the auger screw. Most of the time the flour would build up along the side. We also tested different types of containers.

We also drew drafts to decide the size and placement of the components, to make sure that everything will work together. The plan for monday is to start looking more at the shape and sizes of the containers and testing the water pump.

First prototype of the mixing chamber and the mixing blade

Day 1: Thursday – The Sourdough machine

helenewaldmannLeave a comment

For our final project we have chosen to make a sourdough machine. The target user is the home baking enthusiasts – the person who like to make great bread using their own sourdough.

We discovered the need for a sourdough machine, as we, and people we know have struggled to keep their sourdough alive, especially during busy periods or when going travelling. You can put your sour dough in the fridge, but only for a short period of time. After a week you risk that your sourdough goes bad.

The Sourdough machine will keep the sourdough alive, by mixing the dough, with certain interval, based on the room temperature. Every day or every other day the dough will be fed, which means adding flour and water. After the feeding the machine will mix the dough with flour and water till the mixture is homogeneous.

The user can choose between 3 modes: “Start a new Sourdough”, “Travel mode” and “Keep it Kicking”. The modes are controlled from the webapp.

The Start a new Sourdough setting will mix water and flour to start a sourdough from scratch. When the starter is finished the user turns on “Keeping it Kicking” which is the default setting. On this setting the sourdough is kept alive and the user can put in the dates where he or she is going to bake, so that the machine can make extra sourdough. When the sourdough is not used for baking, the user has to remove some of it every other week or whenever the container is full. If this happens, the user will get a notification. The user will also get a notification if the machine is out of water or flour, no matter the setting.

The Travel mode is for keeping the sourdough alive, when the user is away from home. When starting Travel mode the user will be asked, how many days the Travel mode should be active. They will also be guided through how much sourdough to remove, to make room for the growing dough. On travel mode less water and flour is added every day to keep the dough active and also make sure that the dough can fit in the container and that the machine does not run out of flour and water.

Components

  • 3x stepper motor
  • 3x stepper drivers
  • 3x ultrasonic sensor
  • 1.3 inch OLED screen
  • 1x peristaltic pump
  • 1x RTC
  • BMP module
  • NodeMCU
  • Arduino Uno
  • (Peltier elements)
  • (Weight)

Time schedule

To get a overview of the project we made a timeplan. We decided to aim for being finished with the machine on the 20th of June, to make sure we have time left to finish the report and make the video. We plan to finish everything on the 25th of June, so we will have time on the 26th of June, to make the final preparations for the exam.

Day 1: Thursday – Auger screw prototyping

mcbasseLeave a comment

Today, the first day of 3 week course in mechatronics we have already begun prototyping. Essential to the machine is dosage of flour. We’ve brainstormed several ideas and a simple, versatile solution to control dosage amount is accomblished with the auger screw. This method of controlling dry powder is already well known and established in many machines.

We have to construct our own and have it accostumed to the material attributes of flour. this will require propor testing. From thingyverse we have downloaded an Auger screw as STL file. We modified the file to our liking and begun printing.

Closing in on a project

emiliekjeldsenLeave a comment

For today we had each prepared a concept for project 3 to share with the group. The projects that came up were a ‘keep your sour dough alive’ machine, two different types of instant ice cream makers, a weight with nutrition and recipe information, a wine cooler to keep track of your wine and the temperature, and a smart grill.

After each member had explained their idea, we had a group discussion about what would be most fitting to work on for project 3. The two concepts we saw most potential in were the sour dough machine and the ice cream maker. We discussed the two remaining ideas with Ali, to get guidance and a new angle on it. We learned that it was important to clarify the problem before creating a solution, as we risked solving a ‘self-made’ issue.

We also discussed the most challenging aspect of the two solutions. For the sour dough machine it is measuring the pH-value and dealing with the growing manner of the sour dough. As the machine should add flour and water every day or every other day, there need to be a way to discard excess sour duogh. The challenging aspect of the instant ice cream maker is how to cool the ice cream properly, to achieve a good quality with different types of ice cream.

The next step is to evaluate the two concepts up against each other, so we can make a reasoned decision about which concept we will work on in June.

Project 3 – FOOD

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The subjekt “FOOD” was presented to the mechatronics team. Initially, the group had to adjust to the new topic and the divergent process should be launched. Loosely and firmly, the talk crossed the table with crazy ideas.

Aksel and Sebastian go on their way to Skylab Food and get in touch with Ruberto early. He is open, helpful and comes with some key points to the topic: It is important to find a new topic. A new way of doing things. In the world, there are many alternative ways of processing foodstuffs, which are considered either exclusive, industrial processes or consumed. New technologies need to find their way to the everyday kitchen. In Skylab FOOD, we were shown technologies to cook without heating and an ultrasonic device to evaporate liquid without heating. Common to the technologies is that they have no everyday use – and are therefore an example of what has a potential in the consumer market.

POWER to the Group

We decided to go on an excursion to get new inputs. In power, we asked the staff for new products and technologies within food. First we were shown new product releases, for example a m-hood that is on the table. Next, the group searched the other department’s stores, which offered:

Various coffee machines, blenders, ergonomics, visual design user-friendliness and more. Many products are conventional, as one expects them. Few new products dominate the market, just new models and new designs. In fact, the visit could help us find possible categories, but it is difficult to pinpoint the concrete input.

The project must be based on a user group and an existing problem field. This is the basis and must above all be applied. We returned to skylab and wrapped up the day, by assigning a hometask: Everyone will look into and present an idea that we can work on in the 3-week period.

The final reflections

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The group work

Our group work progress has generally been working really well. At the early stage we experimented a lot, and tried connecting things outside of our exercises. However, one downfall we have had as a group has been, that we have not each individually changed between the tasks. This means that not everyone has tried to make a component inside nodeRED apart from the exercises. We had one time when the work practice was really good: Making the flow diagram, and deciding what the locker should do in different scenarios, made it very clear what tasks should be done. For the next project we will do the flow diagram earlier, define what tasks should be done, and make sure that everyone get to work on all parts of the project.

A new world of things connected to the internet

This project has opened up the world of IoT devices for us. Most interesting is how we could save memory on the nodeMCU, by making cloud computing do most of the tasks for us, by simply communicating with our NodeMCU via MQTT. The nodeRED layout was a very simple way to “program” specific tasks for us. Especially the dashboard functions was amazing to quickly prototype a functional UI, without much knowledge of html and css. Combining it with an MQTT server, made it super easy to send and receive messages (or commands) to the nodeMCU.

It is nice to experiment with making every-day things work on the internet. However as design engineers we must also remember to think about the Raison d’être of our inventions – otherwise they might be chindogu inventions.

The assembly of mechanics and electronics

The construction of the locker was through lots of trial and error. Corners are extremely fragile during assembly, and has costed the lives of a few boxes. We got a tip, that moisturizing the wood before assembly, would make the bendable corners less prone to break. The tip was given post-assembly of the final box, and is therefore something we can take with us to the next project, if bendable laser cut wood still is the thing we want to work with.

We wanted to lessen the resistance in the breadboard, so we could be sure everything would run smoothly, and so no cable would loosen itself during the setup post-assembly. We thought it would be a great idea to solder everything together on the day before delivery, with very little experience in soldering circuits. We got extra cable from the instrument group in building 414. Next time we will ask for something more specific than “cable”, so the instrument group won’t mock us and get a bad impression of Design and Innovation students. In the students workshop in 413 we got a few tips and tricks for creating powerbridges for parallel connections with jumper cables. We got hold of a perfboard which was very helpful on the soldering process.

We were quite excited when we learned that no components was burned in our soldering adventure. With great momentum, we were ready to assemble it. But before we would hide the electronics inside the safe, we had to make sure that it all worked. We had a strange experience with the nodeMCU, that suddenly did not want to connect to our wifi. We re-uploaded the code, and tried to reset it, but nothing worked. We then tried to upload the code on another NodeMCU, and it worked flawlessly. We desoldered the NodeMCU and replaced it with the one that worked. The new NodeMCU now did not want to connect to the wifi. So we tried changing the code, but nothing worked.

The point of no return

At one point we wanted to see if it worked, and plugged in the 12 volt adapter to the nodeMCU. A loud pop went into the room, and we sat back in silence looking at each other. The LEDs had stopped emitting light. It was dead. So we found a third NodeMCU and soldered it onto the board, after cutting loose the old one. And suddenly the wifi was working. So the moral of the story is, sometimes things just don’t work, and if we get stuck, we should try to disassemble everything and try to replace the cables and components.

Project 2: IoT Safe, final overview

akselnladegaardLeave a comment
  1. Introduction
  2. Electric circuit
  3. Dashboard and Node-RED
  4. Buzzer + OLED
  5. The locker

The goal of this projet has been to create a single IoT safe that can be unlocked via a web-browser. We have achieved this by using a node MCU, Node-RED hosted on IBM cloud, using CloudMQQT as our broker and various other hardware components.

The Node-MCU, acts as the hardware controller. It’s code defines its functions but it is at no point in control over the safe, the Node-RED is in charge of what the safe does. This makes it easy to adapt the hardware part of this project to a completely different IoT safe experience.

All Node-MCU functions are triggered via strings over the broker, from Node-RED: Ie. we can play specific buzzer sounds by sending either “success” or “failure”.

The project can be seen as a proof of concept, as it only accounts for one safe. It would require a database to have multiple safes running over one flow. Ideally one could have multiple safes running over one Node-MCU or one central server handling it. Another possibility is just accepting the higher safe costs and each safe running on its own cloud instance, own Node-MCU and so forth.

2. Electric circuit

The electric circuit and components can be analysed via the schematic seen below.

Power Supply:
Our Node-MCU is powered form 12 volt direct current outputted by an adapter. It transforms 220 voltage alternating current from a standard house power plug. This way the locker can be be powered from any outlet. Same adapter delivers power to the solenoid motor inside the electronic lock.

The powered Node-MCU delivers 3 volts direct current to the OLED and the buzzer is powered by the digital output pin D0.

3. Dashboard

The Dashboard, or UI (user interface), is an important facette of the product. It’s the digital front end and it must guide the user. The UI consists of 3 elements.

A presentation element welcomes the user and displays the locker’s status (Available / Occupied). This is connected to the OLED that will also display OLED.

An ‘Unlock’ element asks for passcode. In case the user has already registered with a passcode he/she must enter the code and the closet will automatically unlock. Entering a passcode without registering will display the messages: “Please sign up to use the locker” and if it is in use and the passcode is incorrect: “Wrong password, thief”.

Lastly: The register element. This is where you type your email and passcode. Registering will send the user an email with instructions on how to use the locker along with a link to the UI and the registered password (in case you forget).

The confirmation mail looks as such:

4. Buzzer & OLED

OLED screen

The OLED is located behind a acrylic plate, to give the locker a nicer finish and make the screen look better. The acrylic plate makes the screen more appenrent and it lights up more.

The buzzer is located behind the airholes made to let sounds pass through.

The hole in the buzzer is locate behinde one of the holes, this make the sound go though better. The rest of the holes if for the look of the locker.

5. The locker

We are signing in with e-mail and password, and the locker opens as it should, playing the right tone
An incorrect password played the FAIL-melody.
The correct password opened the locker playing the SUCCESS-melody.
The final Locker

The final locker will open when the user signs up, and it opens again when the user types in their password. The lock is mounted on the wall in Skylab and is fully functional.