Automatic Cornflakes Dispenser (Cerematic)

About: Student MCT Howest Kortrijk

My idea:

For my final project of my first year I was allowed to work out a project that I liked. For me the choice was quickly made. It seemed to me an original idea to automate a cereal dispenser so you can control the machine remotely. After some research it seemed a viable project.

Step 1: Supplies

  • Raspberry Pi Model 3B+
  • T-Cobbler Raspberry Pi
  • Power suply Raspberry Pi
  • Raspberry Pi Case
  • Memory Card 16GB
  • Breadboard (800 pins)
  • 2x Breadboard (400 pins)
  • Jumper Cabels (Male to Male, Female to Male, Female to Female)
  • Resistors
  • LCD Screen (16x2)
  • 2x Loadcell 1KG (+ HX711)
  • 2xI R Obstacle detector
  • 3x IRLZ44N MOSFET
  • Ledstrip 5M Water proof
  • 2x Ultrasonor sensor (HC SR04)
  • L293D Motor Driver
  • 37mm 12V DC 12RPM High Torque Gear
  • PCF8754 (I²C)
  • Power supply 12V 5A
  • Cornflakes dispenser
  • Pipes clamp 13.5cm
  • Connector 10mm
  • Mounting hardware 25mm
  • Set screws (with different sizes and lengths)
  • Set nuts (with different sizes and lengths)
  • Double sided tape
  • White tape 50mm
  • 1m² melamine
  • PVC profile
  • Shrink sleeve
  • Drilling machine
  • Clocking drill
  • Soldering item
  • Tin
  • Screw driver
  • Pliers
  • Miling cutter
  • Saw
  • Saw machine

If you have most of the tools, this project will cost around 200 euros.

You can find the prices and references below this paragraph.

Step 2: Mount the Motor to the Dispenser


Materials for this step:

  • 2x pipes clamp 13.5cm
  • 2x connector 10mm
  • 2x Mounting hardware 25mm
  • 2x 12V DC 12RPM Motor 37mm
  • Screws
  • Nuts

Tools for this step:

  • Drilling machine
  • Clocking drill (approx 45 cm)
  • Wiring cutter
  • Screw driver
  • Soldering item
  • Tin

Description:

Start with removing the hard plastic around the connector untill the iron appears. Remove the ash from the dispenser and mount it to the connector (with a screw driver). Mount the ash (inclusive the connector) back in the dispenser.

Now drill a hole in the middle of the "stand" right in front of the shaft so that we can easily mount our motor. Use approx. 45 mm clocking drill so you definitely have enough place.

Now mount the reservoir back to the "stand" where the connector is now located at the gate that we just drilled.+

Mount now the 12V DC motor to the connector (with the ash of the motor in the connector) so that the motor is fixed into the gate that we've drilled.

If your pipes clamp is too large for the engine that you have bought, I suggest you to mount 2 layers of thin rubber at the motor so we can firmly clamp the tubes.

Now mount the pipes clamp to the motor using 3 short screws.

The last step is now is mounting the mounting hardware to the "Stander".

To do this, drill 2 gates under each other which make it possible to assemble our mounting hardware here. (See photos)

Now mount the mounting hardware to the "Stander"' using 2 nuts, 2 screws and 2 trays to make our setup strong.

Make sure that this is a sturdy construction that makes it not possible to run the motor around himself.

Maybe it's still safer to get some rubber between the "stand" and the dispenser to fit, so that our reservoir certainly does not break when the engine is running. (See photos)

Do this step for both the left and right dispenser.

If last soldering jumper cables to the + and - of the engine to our circuit.

Step 3: Mount the Sonor Sensor to the Reservoir


Materials for this step:

  • 2x ultra sonor sensor (HC SR04)
  • Double sided tape

Tools for this step:

  • Drilling machine

Description:

Now drill a gate of approx 2x2 cm into the lid so we can mount our pins of the ulta sonor sensor to our raspberry pi.

Then mount at the bottom of the HC SR04 a piece of double-sided tape so we can easily mount our HC SR04 at the lid of the reservoir. This step will make our electronic circuit later much easier.

Step 4: Drill 2 Gates at the Bottom


Tools for this step:

  • Drilling machine
  • Clocking driller

Description:

Drill with the greatest possible beat drills the 2 platforms from where the bowls go on. We do this because we later in our circuit our 2 load cells will be placed there so we can measure our weight of the bowls.

Step 5: Make the Case


Materials for this step:

  • 1m² melamine
  • Screws

Tools for this step:

  • Drilling machine
  • Miling cutter
  • Saw machine

Description:

Since I never have studied in a technical school, and our direction here either I have focused on using a friend for making the case. It went for me what to be complex because I have never been using a miling cutter etc.

I have given my friend 2 documents where he knew enough to realize the casing (see photos)

If you want to make the case himself, there are some pictures at this step that show how the end result should look like. Specific dimensions are in the first 2 pictures.

Step 6: Mouting the PVC at the Back of the Case


Materials for this step:

  • PVC profiles (approx 2.5cm thick)
  • Double sided tape

Tools for this step:

  • Saw

Description:

Still some details should be finished to our enclosure. In this step we go mount the led strips to the back of the case for the best visual effect.

Saw the PVC profile in pieces (2x 55cm and 1x45cm)

Now we have the perfect dimensions for the profiles. Therefore, paste some double sided tape at the PVC profiles so the back of the profile is on the outside (and the open side on the inside) and paste it to our enclosure.

Paste as last the led strips in the PVC profiles and make that the control of the led strips is to the left corner down (this is important to control our led strips later). Make sure to cut the ledstrips on the right place.

So you get the result in the above photos.

Step 7: Mounting the Load Cell to the Case


Materials for this step:

  • 2x Load cell
  • 2x HX711
  • Jumper cables
  • Heat shrink tubing
  • 4x long screw
  • 4x short screw
  • 4x nuts
  • Hard cartonboard

Tools for this step

  • Soldering item
  • Tin
  • Screw driver
  • Drilling machine
  • Lighter

Description:

Since the load cell works with a strain gauge, this module should be mounted on a special way. The load cell should not rest on a flat surface, hence this extra step is needed.

Since the wires of the load cell are very small, it is necessary to solder 4 jumper cables to the loadcell (so we can switch them easier). Use a soldering item and tin to connect them with each other.

In our case there are already 2 holes machined on the bottom. We start with the leftmost hole.

Drill 2 holes through the bottom (1 x 1 cm to the right of the left hole, and another 1.5 cm to the right of the left hole)

Now insert 2 long screws through the bottom by the 2 holes of the loadcell, and attach using a nut (see photos). Make sure that the load cell is NOT resting on the bottom. Make that the loadcell module still can move a little bit (but not too much!)

Now do the same for the other side, but identical drill the 2 holes 1 cm to the left of the right hole and 1.5 cm to the left of the right hole.

So you get the result in the above photos.

Finally, it is useful to create another kind of ' platform ' on the load cell so we can easily put something on that platform.

For this I used a piece of hard cardboard and I have 2 holes drilled in the middle.

Then mount the spools stuck to the load cell with the help of 2 short screws (make that firmly!)

Do this for both load cells.

Step 8: Drill Gates to Supply the Case for Power


Materials for this step:

  • Drilling machine

Description:

Now drill a hole of about 2 cm x 2 cm. Drill this hole in the left corner at the bottom (where we have the control in step 6 of the led Strip fitted). Now insert the Steering, power supply of the Pi, power supply of the led strips and the control of the led strips through the hole.

Step 9: Electronics


Materials for this step:

  • 2x HX711
  • 2x Load cell
  • 2x Object detector
  • Resistors
  • 2x Sonor sensor
  • 2x Motors
  • L293D
  • RGB connector
  • LCD Screen
  • PCF8754
  • 2 Buttons
  • T-cobbler
  • 1x Breadboard (800 pins)
  • 2x Breadboard (400 pins)
  • Power supply 12V 5A

Tools for this step:

  • Double sided tape
  • White tape

Make the above schedule on the breadboards.

Mounting the LCD screen:

Select the PCF along with the LCD screen as on the above schedule. I pasted the bottom of the breadboard to the top of our housing. Now insert the LCD screen through the hole that we have machined.

Mounting Object Detectors:

Paste at the bottom of the 2 object detectors double-sided tape and paste it at the bottom of the 2 platforms that we have already mounted.

Mounting power supply:

Paste at the bottom of the power supply 2 double-sided tapes and paste this to the back of the case. Connect the + the + and the - with -

Close all other sensors to the breadboards as in the above schedule.

When finish you can get over all cables white tape.

Step 10: Mount the Sensor to the Dispneser

Now mount all sensors and motors to to the dispenser.

So you get the above result

Step 11: Configuration Raspberry Pi

Make sure that all busses are disabled, so we can use the GPIO pins.Enter the following commands

sudo apt-get update
sudo apt-get upgrade

Step 12: Database

Upload the SQL file in MariaDB and test if you can view all the tables.

Step 13: Code

Git and clone the link below https://github.com/LennertDefauw/Cerematic. This is the code of the project.

Enter the following commands in putty

nano /etc/rc.local

Type the following rule at the bottom of the page:

python3 /home/pi/project/app.py

Step 14: The End

The project is done! Surf to the IP address on the LCD screen comes up and you can remotely control the machine,.

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