Introduction: Laser Pointing Cactus

For a project in school, I had to make something with Arduino, I wanted to make something for a cat, that you can trigger and will play with the cat by itself. I first thought of a mouse but it was a bit difficult to make something so small with that much tech in it. After the mouse idea which was designed to be interesting for the cat, I decided that it was, even more, interesting to design something that would be a plaything for the cat and it's hidden in a cool thing. Thing later turned into a flower, later I decided that it would be a cactus (because cactuses are cool). It was that moment the “Laser pointing cactus” came to me. It’s an automated toy for your cat, in a cactus, fashionable and handy. For playthings for cats is always something that is visibly a toy this is not something like that. It is also a pleasure to look at although it is not something that is really realistic, it's really cute I think. The cactus is made from cardboard, this is because if it falls (cats are often bullies ;P), it wouldn't break.

To make this I used these items:


  • Arduino UNO
  • 6 by 6mm button
  • Male to male jumpers
  • Laser
  • 2 Mirrors
  • 2 mini servo’s
  • Breadboard (For testing)
  • Solder Board
  • Cable Soft
  • 2 resistors ()

Step 1: Idea Laser Pointer

So, for my laser to move I need to build a system that can move the laser horizontally and vertically, what I came up with is the servos with mirror’s placed above each other so that you can move the laser with turning your mirror. With placement, you can make sure it can make the laser move both ways horizontal as vertical.

A picture to “paint the picture” probably makes it more clear, what we need to do is program the servos to not only move randomly but to move just a little part of what they can realize. And a laser pointer you can always turn off so we also need to install that.

Step 2: Getting Your Arduino Set Up (For Real)

Now we are ready to build our laser pointer system. You´re first going to install it on your breadboard to test your setup, after that you can put it on your solder board and solder it all together. But first the breadboard of course, I used this code but for that you need to put your INPUT´s and OUTPUT in certain pins, the servo´s yellow wire you have to put in pin 10 and 11 for this code to work, the laser has to be connected with pin 12 and the button has to be connected with pin 3. You can choose yourself to use the pins you want and to adjust this in your own code. The button in pin 3 is rather important because I placed an interrupt on this pin, with the Arduino UNO model you can only put an interrupt connected to pin 2 or 3, so make sure you use one of those for the button.

Important also is to connect the pin into the Arduino with the resistor and the sensor or button, this is so you can control your connected object.

Here you can see and download my code to use.

Step 3: Last But Definitely Not Least

THE CACTUS! We got everything except for that, I used a piece of cardboard and with the help of cutting it partly I could curl it up like a circle, the pot I had lying around somewhere, so I used this also as something the cactus could stand on. I used multiple colours of green paper and glue to make sure it has the colour of cactus. Make sure you make a hole in the "ground" to put your wiring through so you can put your Arduino and a battery or a power bank in the pot. For the tip, I used a balloon and paper maché (also the same colour theme). Then the hard part, it's getting the servo's in there, I used multiple "bridges of cardboard" and used these to put the servos on, these do need to be fixated there so you can tape them or glue them (Warning: only glue them if they are in the right position!!!) The laser above the lowest servo nest to the highest servo also needs to stay in one place, I did it like the picture above.

Then you need to map your laser, I suggest you do this by changing the rand1 and rand2 to 0, that will be your starting value, you need to but your mirrors as far as they can without the laser falling off the mirrors, for me this was the left under corner. Like this, you try to map how much you degrees you want your servos to turn, then you will need to cut a gap in the cactus so that the laser can be seen in the room.