Introduction: Human Auto Feeder 0.5

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Welcome to my very first instructable about making a (sh*tty) feeder bot!

In this instructable, I will try my best to explain how I made this bot step by step with the required procedures, materials and tools!

The table of contents:

  1. Materials & Tools
  2. Laser cutting .ai / .svg files
  3. 3D printing the extension
  4. Constructing the neck
  5. Constructing the base
  6. Constructing the head
  7. Hooking up the electronics
  8. Constructing the conveyor belt
  9. Closure

Tighten your seat belt (as well as your wallet) and let's have a look!


arc_lag is in no way responsible for any bodily or psychological harm one might bring upon him/her self during the making of the feeder bot

Ps. Miss Tode, if you're reading this then hi! And sorry for the horrible design as well as the instructable.

Step 1: Materials & Tools

I will be using metric units to convey dimensions.


  • 3 wooden plates with the dimensions of (length*width*height) 600*300*3 mm
  • Wood glue (You wont be using the entire bottle of glue)
  • Solder
  • A lot of jumper wires to connect everything
  • A little piece of rubber which you can attach (or glue) to the end of the dc-motor


  • Some clamps to keep the construction together while the glue is drying
  • Caliper
  • Arduino Uno
  • HC-SR04 Ultrasonic distance sensor
  • An Arduino capable button (any button with two pins should suffice)
  • Soldering iron
  • Glue gun (a minimum amount of 5 glue sticks)
  • An electrical relay (the one I used in my iteration is the Takamisawa RY-05W-K)
  • two pens for the conveyor belt system (discard the ink of the pens, they are not used. We mainly want to use the casings. The pens should be straight as possible, imagine something like a bic pen but circular )
  • A file (only for the last straw during assembly)
  • A 3D printer which can print 200*200 mm large objects
  • A laser cutter/engraver which can accommodate 600 * 300 large slices of wood
  • A knife or saw to cut the ends of the pens

I made use of a laser cutter (Trotec Speedy 100) to cut everything in a precise and controlled matter. You may not be able to put everything together nicely if you decide to use something like a saw

Step 2: Laser Cutting .ai/.svg Files

As you can see, I used the Trotec 100 to get get everything cut out nicely.

The files I have annexed are the so called 'blueprints' for the trotec engraver, they're specifically edited so that the lines are 0,01 mm thick and they are all coloured red (255,0,0 in RGB code. No CMYK). That is how the trotec laser engraver understands what it needs to cut. This may not be case for you if you are using any other laser engraver/cutter so bear in mind that you might need to give your own twist to the annexed files!

Consult the manual of your engrave/cutter to get the best results.

If you've managed to cut out everything.. let's continue :)

Step 3: Neck Assembly

Alright time for a bit of assembly!

After taking your pieces out of the engraver/cutter

The way I began working on the robot was by starting with the neck piece.

  1. I took some wood glue and glued all the ridges on to each other until I got the following result. The joints are all perfectly aligned so just stick them right on to each other, clamp them tight and let it rest for a minute or 5~10 (depending on the amount of glue you have used).
  2. Be sure that everything is firmly stuck to each other, don't be scared of giving it a little tug to check if all the parts are connected firmly. You will know that it's alright if it doesn't budge at all

If everything went well, your caliper should give around the same length mine gives in the picture, if not then no worries, it should fit nonetheless in to the base (if it really doesn't fit, rasping it with a file would do the trick).

Step 4: Base Assembly

Okay the base is a bit more tricky.

The procedure doesn't deviate a lot from the neck piece. The only way it deviates is that I could not use the clamp and had to hold everything together myself.

  1. Don't glue the top sides of the long wooden pieces, the top plate needs to be moved freely and not be secured.
  2. Glue the ridges(not the ridges that make contact with the top plate) of the long pieces with wood glue
  3. Stick them on the base plate which has no holes in it
  4. Hold everything together for 3~5 minutes (it's fine to do one piece at a time as holding everything together in one go is nearly impossible)

The clamps I had access to were not long enough to clamp everything down So I had to actually wait for for every individual piece to dry out and keeping them together my self at the same time :( By all means don't repeat my mistake, if you have access to tools that could replace the clamps, go for it.

Step 5: 3D Printing the Extension

If you have a keen eye and checked through some photos, you will have noticed that I did not have a 3D printed part in my robot. As I did not have the time and opportunity to print it, I more or less did the entire thing with some wood and a glue gun as an improvised 3D printer

However, for the people that do have a 3D printer at hand and you actually can wait for an extended period of time. There is an .STL file added to this page which contains the 3D design I made for the head extension. The printing time can deviate due to printer settings so consult your printer manual for the best possible result!

Use your biggest possible nozzle since we're not looking for detail here and a bigger nozzle means faster printing!

>sidenote< I made a horrible improvisation, as you can see in the annexed picture. That's what you get for being poor and impatient.>/sidenote<

Step 6: Assembling the Head

We're almost there!

The headpiece is perhaps one of the most complex part of the robot, not because of the electronics but because a lot of parts meet up there.

Just like the base we made, we're not going to glue everything together and since all the parts are fairly similar in size (all 12*12), we shouldn't have to hassle as much as we did with the previous base.

  1. There is a piece with a rectangular cut-out, leave that alone for now.
  2. Glue everything together like the second picture suggests. The procedure of gluing them is the same as the previous ones but don't glue the sides which are going to accommodate the piece with the rectangular cut-out.
  3. The piece with the large and small hole (seen on picture 4) needs to be on the left side on the cube as the rectangular piece is considered the front, those will be the holder and throughput for the DC-Motor which we will be working on in the next step
  4. If done correctly, you should now have a ¬(semi-beautiful)* cube.

The head doesn't need to be glued on the neck as placing the electronics will become much harder than necessary.

The extension should be placed and glued 6 mm in front of the small hole, I used my glue gun to place it properly, after gluing the pieces together as the first two annexed pictures show. try c

* ¬ meaning not/negation in logic

Step 7: Hooking Up the Electronics

We're almost there!

Let's begin with the code for the Arduino first!

  1. Connect your Arduino to your computer and try uploading the following code in advance:
  2. Link to my C code, just copy and paste it in to your Arduino software

After doing this, let's get to the circuit!

Keep the diagram I uploaded closely at hand! That will be the entire circuit. Take a look at the 2nd picture which shows how the Arduino should be placed inside the neck and connected with the relay. Picture 3 and 4 are there for reference

After assembling/soldering everything together (except for the DC-motor pins, quickly skim through the next step, procedure to get an idea why) you should cram everything inside the neck except for the sensor and the DC-motor, they need to pass through the entire neck in order to get to the head piece. Not elegant but who cares about elegance or functionality... :)

( I actually do but it was too late, I realised a lot of things after assembling the entire construction so yeah... I would've done things otherwise if I hadn't already passed the point of no return.)

Try making a test run, if everything has been followed this far, you should be able to see some result by putting the sensor closer or further away from an object (eg the motor spinning or some clicking noises from the relay)!

If that's the case, great! we can get in to some more details now, especially fine tuning and getting some form of a conveyor belt to eject cookies or snacks at C* speed

* C, used to denote speed of light which is 300.000 km/s

>side-note< I've come to notice that my DC-Motor hasn't been really up to the task of providing adequate torque/power, perhaps if I ever decide to make a better revision, I will go for something bigger with a potentiometer so that I can regulate the power and what not >/side-note<

Step 8: Constructing the Conveyor Belt

I can safely say that we've reached the 7/8th milestone, are you enjoying it this far? I certainly ¬(did)!

Now this is perhaps the trickiest part as this involves some improvisation from your own side.


  1. 2 straight pens
  2. Some thin, long objects that can pass through the pens and act as support x2
  3. Knife or a saw to cut the ends of the pen
  4. Some really small piece of rubber (it might be hard to see but on the second picture, on the right side of the pen, you can see a black spot sticking out. That is some rubber I had to get pierced by the DC--motor so that it made proper contact with the pen)
  5. textile


  1. Cut the ends of the pens out
  2. Stick the rubber on to the DC-motor
  3. hot glue the rubber piece and quickly put it inside a pen (The alignment of the DC-motor and pen should be straight, It's unreasonable what I ask of you but you don't want the conveyor belt to weeble wobble around.)
  4. Stick the DC-motor through the side mount as seen on picture 3
  5. Try routing the DC-motor cables through the little hole next to it and hook it up with the rest of the circuit. It is also safe to solder the cables to the motor pins now.
  6. Hook the textile up before securing the other side of the motor with a pin for support, as you won't be able to get it out anymore. Secure the pin or object of choice with hot glue
  7. Repeat the idea of picture 3, don't forget to get the second pen in place together with the textile before securing the pin or object of choice in place.
  8. ???
  9. Finished!

*procedure 9.1 maybe hot glue the head piece on to the neck now instead of letting it dangle around and disconnecting the cables whenever it falls.

>side-note< I'm fully aware that the DC-Motor I'm using right now is not one of the best ones available as it just chokes whenever something heavy is put on the conveyor belt. That's why I decided to use a relay with a separate 9V batter, as only the power source of the Arduino was not enough. This helped to a certain extend but it was not enough to move a single cut KitKat bar >/side-note<

Step 9: Closure

Open the mp4 file if you want a demo of how it launches some stuff out of the conveyor belt.
As you can see, the robot is completely useless but it's here nonetheless for educational purposes.

On the remaining 2 pictures, you can see how the conveyor belt is finally set up and how I routed the cables from the neck.

Grade F if you've been able to reproduce this mess.

Grade A+ if you stopped halfway

Thank you for reading through this guide. And do share your own version with everyone else! It's only courtesy to share your adaptation with the others so that we can learn from each other!