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What will it do?
**Goal is to create a kitchen appliance that can wash and dry greens and other vegetables via a pre set cycle both saving time (and potentially water)**
**Who's done what beforehand?**
So far I only found limited similar project within the fab academy community and a few outside.
Fab Academy projects
1) [here](https://fab.cba.mit.edu/classes/863.13/people/jfduval/final.html)
Outside of fab academy:
1. I like the automated spinning salad dryer that the You Tuber The Practical Engineer designed
<iframe width="560" height="315" src="https://www.youtube.com/embed/hfGojmXrGfc" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen></iframe>
I think that he has a good spinner design and using this approach can allow me to allow users to put in
any colander they wish.
2. Commercial solution are mainly ultrasonic, manual or focused on drying (salad spinners)
[Here](https://www.amazon.com/dp/B0BCVW1DPR?pd_rd_i=B0BCVW1DPR&pf_rd_p=b000e0a0-9e93-480f-bf78-a83c8136dfcb&pf_rd_r=SXKKN0NRSWW8SSBCYA6G&pd_rd_wg=yaMUE&pd_rd_w=RtpxZ&pd_rd_r=91c7961a-a2a2-4e3e-a877-a44317f81a64) are some examples
**What will you design?**
I will design all aspect of the project with 4 major components
1) The box / frame of the machine and water reservoir
2) The spinning mechanism
3) The machine lid and water dispensing mechanism
4) Control board electronics - main board, pump breakout board, motor breakout board, button breakout board
**What materials and components will be used?**
The main materials are
1) T Rails + Plexiglass
2) 3D print filament - TPU, PLA and XTC3D finishing resin
3) Electronic components and PCB boards, motor/ESC and pump
4) Molding plastic / rubber
Below is a full BOM
**Where will come from?**
Most are either provided by lab, purchased from Digi key or Amazon
**How much will they cost?**
**What parts and systems will be made?**
Washbasin/box/frame, drain/skirt, spinning plate, lid, water reservoir, electronics boards.
Only things not made are:
Motor + ESC, pump, salad spinner bowl, water tube, sprinkler head, power supply
**What processes will be used?**
- 3D print
- Laser cutting
- PCB Board milling
- Molding and casting / resin
- System integration
**What questions need to be answered?**
- Spinning mechanism - chain/band vs. direct drive (already answered)
- Frame materials - (already answered - TRail )
- Water drainage approach - TPU printed sloped base
**How will it be evaluated?**
- does it wash and clean greens / veggies
**Under what license is the project**
The project is published under the
[Creative Commons Attribution-NonCommercial 4.0 International License](https://creativecommons.org/licenses/by-nc/4.0/)
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## Project description
{: style="height:360px;width:720px"}
{: style="height:300px;width:300px"}
Here is a first cut at the base:
**There are 4 main parts to the appliance**
1. Water reservoir
2. Main container (Wash basin)- base is designed to have a gravity fed drain
3. Lid with build in sprinkler
4. Vegetable holding bowel that sites in the Wash basin and spins to dry
**There are 2 Motor/pump used**
1. Water pump to move water from reservoir to sprinkler head
2. Motor to spin Vegetable bowel
**There are 2 potential sensors**
1. Lid sensor - stop operation if lid is open mid cycle
2. Water level sensor to alert if reservoir is empty
**Microcontroller usage**
1. Control sequencing of pumps / motors
2. Interrupt operation if sensor is triggered
3. Manage GUI
**GUI**
- Wash only
- Dry only
- Wash/dry
Here is a another view of the merging design
| Weekly topics | Parts |
| ----------- | ----------- |
| Computer controlled cutting | Outbox / wash basin holder |
| Electronics production | Controller, motor ESC, Sensors |
| 3D Scanning and printing | Motor housing, water connectors, sprinkler head, sproket/chain for motor drive|
| Electronics design | sensors / controller board / Motor ESC |
| Computer controlled machining | Controller board |
| Embedded programming | Cycle design / User input |
| Molding and casting | Drain / Spinning plate |
| Input devices | GUI buttons / Sensors |
| Output devices | Screen |
Controller board / Pump driver / button and sensor break out board - PCB milling
Purchased - ESC, motor, pump, power supply, water bottle/reservoir, spinner bowel
My build split into the physical build and the electronics with notation of pins connected to each breakout board.
I decided to use a similar method that we used in machine week of T rails for the outside frame and then 1/4 inch plexiglass for the water tight box and water reservoir that are both mounted in side the frame
Using a chop saw and aluminum cutting blade I got all the pieces ready for assembly
3D printed bracket will be key together with T Rail M5 screws and bolts
To make the water proof interior box I decided to use 1/4 plexiglass that I will laser cut and then use cement and possible silicon to water proof
I used the big epilog laser at the fab lab. Setting for 1/4 inch plexi glass was 100% power and 10% speed.
I first cut and assembled a cardboard set to make sure it all worked well as I only have 1 sheet of plexiglass. I made sure the mounting holes for the motor were positioned correctly
Now it was time to cut the plexiglass
4 of the five panels cut fine on the left side but the right side of the laser did not cut through. I refocused the laser on the right side and ran the cut for the 5th panel with 3 passes. Discussing with the person in charge of maintaining the laser it seems like they were having a focus issue they were working through.
Now I needed to glue it together and so I used a plexiglass cement with the following [data sheet](https://assemblyadhesives.com/SDS/WELD-ON%204SC%20Low%20VOC%20Solvent%20Cement%20for%20Acrylic%20US_EN_v2.pdf)
I only did used it in the garage with the car door open to ensure enough ventilation
This applicator was very useful
I used clamps to keep it together until the cement dried
The lid assemble was a smaller version of the box assembly with an addition of a hinge and a Door Lift Stay Support Hinge Damper [](https://www.amazon.com/gp/product/B01N5GQZK2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1)
Now it is time to fabricate the internal plexiglass box including screw holes to mount the sprinkler head
First I cut out the shape from cardboard to make sure it would fit
Looks good
Now cut the plexiglass
Clean cut
Here you can see the water pump mounted and another hole for the water tube to go into the lid
And here it is with the spinkler mounted.
First I set up some user parameters I will use in sizing the spinning plate and it base
To create the shape of the base I will create a new sketch on the top of the base leg. I then
create a circle and replicate it using the circular pattern tool followed but a cut.
I then sketched on top again and created a circle to create the plate itself
Here I made a mistake as I did not select the whole plate and where the handy timeline
tool come into play
And we are back on track. I wanted to create a downward facing lip in order to provide some water
protection for the spinning mechanism during the dry cycle.
To do this I am going to draw a sketch of the lip and have it rotate around the plate center axis
Start with sketch
Then used the revolve to create the lip and set it to join the plate base.
and there you go a first cut at the base plate
After 5 hours, here it is:
When I put it up to the salad spinner bowel I have it seemed to me that the overall size of the machine \
can be much smaller then I originaly planned.
I think a good approach is the max the size of the plate I can print on the MK3S
The original size had a 320mm diameter but I am going to resize it to a 200mm diameter
I used the scale command leaving the Z as is and scaling the X and Y to 62.5% of the original
Now that I liked that size in order to make every thing work in fusion I had to go back and resize the plate in fusion to match.
Now we are ready to create the bowel holders
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See below for discussion on the motor drive selection and decision to move to a direct drive mount on a outrunner motor. I am used a D3548.
I found a model of the motor I am planning to use on GrabCad
This an out runner and I would like to cut its shape into the bottom of the spinner to test a direct drive
As the CAD was made of many many pieces it was easier to create a similar shaped body. I traced the profile and used the revolved function to create an new body
s
Now I used the combined command to cut this out of the base of the plate for a direct mount
Creating a nice mount for the plate - i also think i do not need the spinner base any more.
I knew there was going to be a lot of stress on this when the plate spins so I filet everything I could to strength the joints.
Got it ready to 3D print
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Initially I printed a basic arm to get a physical sense of the shape and size
After have a basic shape in the early design I needed to have a pieces that was help in place on the plate.
I started by adding a wedge at the plate level and tweaking the shape but it was very unstable
I decided to use to features to do that.
1) Redesign the base to snugly fit on the shape of the plate
2) Create a threaded rod on the bottom and print a nut that will hold the are in place
<iframe width="560" height="315" src=../../images/Finalproject/Bowlfly.mp4 frameborder="0" allowfullscreen></iframe>
When discussing my progress with my local instructure Dr. Fagan, the feedback I got is the need to have a screw to hold the plate to the motor shaft
Once the design looked goo it is time to reprint the plate.
<iframe width="560" height="315" src=../../projects/Plate/newplate.mp4 frameborder="0" allowfullscreen></iframe>
To ensure the spinner bowel does not fly out I need to add a hooks that will connect to the top of the plate arms and hols the bowel in place
I decided to go with a simple 3D printed design
Got them 3D printed
And istalled
After some testing i found out that the hooks allowed the bowel to have too much motion that got out of hand when the RPM went up.
So I redesign the hooks to have a tighter fit with the bowel.
I also replaced the bolt with zip ties as the bolts came loose over time. These 2 changes got the bowel in with a tight fit that works well.
## Box: Water reservoir
I had decided to use a square water container as the water reservoir
I wanted to build a holder that will attached ot the back of the frame and hold the water bottle
I added strong support to try and only connect it on the bottom rail
And we are ready to print
<iframe width="560" height="315" src=../../projects/Frame/Waterholdprint.mp4 frameborder="0" allowfullscreen></iframe>
Looks like a good fit
3 M5 screws secure the holder to the frame
And here it is mounted and full of water
My plan for water profing the motor and providing a gravity based drainage is to create a sloped rubber base for box with a rasied skirt.
The skirt will go between the motor and the plate lip thus stopping any water for getting into the motor.
I started with a fusion design
Added the drainage slopes
Unfortunately my Prusa is too small to print the whole things at one so I had to cut it to be printed in parts
Printing in TPU is slow if you do not want stringing It is a 23 hour print !!
Here it is in progress
Fully printed
Printing went well but remove the print from the plate was nearly impossible and ended up destrying the plate.
This did not happen to me in smaller prints I did but after going back and reviewing the Prusa [materials guide](https://help.prusa3d.com/materials#_ga=2.250429327.883239654.1684193727-1420350994.1684193726) as well as reading some user form it seems that I missed the need to either
1) Add a layer of glue stick
2) Put down blue tape the print on
After reivew it seems that Loctite 406 is a recommended glu for TPU so that is what I am going to use to turn these 3 parts into 1. But before I do that I can see 2 things that I need to add and adjust:
1. Add a drain connection
2. Expand the neck to fit the screw that I added to the plate
I created a drain connection / edge
Ready to print
Here it is
I also cut the next of the skirt to fit the new screw placemen.
I needed to connect the different parts of the bottom into one
Some reaserch showed that for TPU loctite 406 is a good option.
I used ducktape on the bottom hold the pieces together until the glue dried
after some more tests that drain was working well.
<iframe width="560" height="315" src=../../projects/Plate/draintest.mp4 frameborder="0" allowfullscreen></iframe>
The drain worked well but i still got a lot of water under the TPU base from all the side.
I decided to use some clear silicon to waterproof the edges and funnel all the water into the drain
And we are ready to go
Unfortunately over the next 2 days the caulk did not cure and was a mess. I ended up taking off the base, cleaning out as much of the caulk as I could and resealing it with silicon which cured much better.
## Box: Feet
I used molding and casting to make mushroom shaped feet for the machine.
Here you can see the design
Milled out of wax
Running a roughing pass followed by finishing pass
Cast a rubber mold
Plastic legs ready to go
And here they are mounted
## Box: Decorative design
To help hide the silicon on the bottom of the box I found a garden silhouette.
For the side I added a square cut out for the drain
I then cut it out of 1/8 inch plexiglass
and then I mounted them which worked out well
Here is the front
and the side
## Box: Sprinkler head
The machine needs a spinkler head and so started up fusion. It will be secured to the LID from the inside and will be feed by the 3/8 hose coming in from the pump.
I ended up making the walls too thin and so it was very brittle during the print
I added more fortification and a square peg on each side I will use to mount into the lid
I went through a number of priting settings to try and get this working as consistently the incoming connection kept have water leaking.
I fortified the design, moved the square overhand to cover the bend of the pipe and reduced the printing layers to 0.15mm. I also added 2 screw holes to mount onto lid.
And here is the final version
1. 12-24V power supply
2. 12-24V / 80W DC Motor
3. 12-24V Motor ESC
The ESC is controlled by a Potentiometer and once I got them connected they all worked well together. When
I turned the knob the motor speed changed.
I want to be able to control the ESC with the microcontroller so I can adjust the speed for the wash and
dry cycles.
First I need to understand how the Potentiometer works with the ESC. There is a plug with power and ground on either side
the middle wire voltage change based on the potentiometer position ranging from 0.5V to 3.6V.
I was not sure how to approach this, my initial plan was to use 2 resistors and some relays to switch between
2 speeds. After reviewing Dr. Gershenfeld class and reflecting on the transistor discussion I came up with the
idea of used a transistor to replace the potentiometer and a capacitor to smooth out the control signal from the microcontroller.
I ran this by our local instructor Mr. Dubick and my classmate Adam Durrett that have strong electronics background and they
agreed it should work!!!
I decided the set up the board to control both the motor the spin the Vesgtable Basket as well as the Water pump even
though my focus this week was on the motor.
For each I would have a control signal come in from the micro controller on the main board. I would change the frequency of
the signal the change the speed, putting a capacitor on the line would smooth it and would replace the line in with the
potentiometer.
Not to get things a bit more organized. It is a relatively simple circuit
Not pushed it to the 2B Board and started tracing
Pushed to the 3D board get ready to mill
When I reviewing the milling it was very tight due to the tracing.
I reviewed the connectors and saw that by switch a few things around I could simplify the tracing
and provide more space between traces to make for easier milling
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Now I was ready to mill. I used the same set up with my Genmitsu 3020-Pro-Max from last week [here](https://fabacademy.org/2023/labs/charlotte/students/dan-stone/assignments/week09/#tool-path-set-up)
The tool path looked good
Got to cutting using a 0.8mm end mill
I deburred and washed the board
Now we are ready to stuff and solder
Here are all the components
And we are ready to test
After stripping the connectors on a number of boards and after rethinking the machine design I decided the break this board into
2 one for the motor and one for the pump.
I also increased the side of my traces to 30mil and replace the pad for my connector with A better connector from
the fab library
I started testing the board and it seemed like now matter what I did the Sources and Drain of the transistor was always connected.
I checked for shorts, I added a pull down resistor to ensure the gate is 0 and not joy. The source and drain are connected.
I went back to the lab and got another 2 transisotr (the lab only had 3 of them) and they all seemed to do that same.
I reviewed them with my instructure and fellow student who is an electrical engineer and they could not find why it was
acting this way other then it may be a bad batch of transistors. We put in an order for some more and for now this part
of the project is on hold until the arrive.
While this effort was on hold we completed Machine Building week and that changed my mind on how to set up the motor.
After a success full machine week I got appreciation for the out runner motor capabilities and so I decided to try and mount the plat directly on a out runner motor and see if that work.
I had a outrunner motor in the lab that was bigger then the one we used in machine week and I think would work well.
Here is it spec:
I coupled that with a large ESC with the following [user manual](https://www.rcelectricparts.com/classic-esc-user-guide.html#03)
I decided to test the motor using a potentiometer to control the speed so I can find out what are good speeds for my final project.
I set up the mounting bracket on the motor
I used a scrap piece of wood to mount the motor onto the frame
Power: The motor will connect directly to the 0-24V power supply I have
ESC control: the ESC will be connect to the BOD via 3 wires: 5V / GND / and PMW from pin D0
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I wired a potentiometer to analog input A1 and the 5V/GND and ran the following code:
```c
# include <Servo.h>
// create a Servo object to control the ESC
Servo esc;
int potVal;
void setup() {
// set the baud rate for serial communication
Serial.begin(9600);
// attach the ESC to pin 9
esc.attach(9, 1000, 2000); // the second and third parameters are the minimum and maximum pulse widths
int potVal;
esc.write(0); //arm ESP
delay(1000);
}
void loop() {
// set the speed to half of the maximum (which is 180)
potVal = analogRead(A1); // read input from potentiometer.
int speed = map(potVal,0, 1023, 0, 180); // maps potentiometer values to PWM val
// send the speed to the ESC
esc.write(speed);
// print the speed to the serial monitor
Serial.print("Speed: ");
Serial.println(speed);