I made a simple robot with basic functions that can be used to teach kids how to code and many more.
The robot is pretty inexpensive can can be made with a budged of about 10€.Its my first robot so far and I will show you what you can do with him and how to build him.
His main features are:
- Easy to build
- Can move his arms and legs
- He is able to move forward
- He can sens if anything is in front of him and react on it
- His parts are relative fast to print (compared to other robot-projects you can find)
4x SG90 Servo
1x HC-SR04 Ultrasonic sensor
1x Arduino nano
1x 9V Battery
1x 9V Battery cable/connector
PLA of your choice
Step 1: The Setup
For testing everything just connect all the parts as shown in the plan and test it with the script. If you use other ports, just change them in the script but be aware and use ports for the servos that got a pwm-function (otherwise it will not work)
The scipt will let two servos work the whole time (like he is moving) and the other two servos will only work if something near enough to the ultrasonic sensor. You also can activate serial view and see if the ultrasonic sensor reacts as you wish.
Why these parts?
The SG90 servo is pretty common and easy to get. He got a 180° range what fits totally.
You should be able to use any ultrasonic sensor but the HC-SR04 is also pretty common and easy to get. He will also fit perfect in the corpus of our robot.
The arduino nano is very small but got all the features as his bigger brother the arduino uno. To power him we simply have to solder the cables of the 9V-Battery connector with the VIN and GND ports of the board.
All these parts are pretty cheap and if you buy them directly from the china-shop of your choice you will not pay more than 10€ for the whole robot.
Step 2: Printing the Parts
The parts are easy to print except the main corpus needs a bit more supporting material. Just put the percentage on 20% if not already set. Otherwise you will get problems with the holders for the arm servos.
The other parts can be printed with 15% supporting material.
Just place them in your slicer as shown in the pictures.
Scale all the objects to 50%!
All parts should be printed in 7-8h.
Remove the supporting material and check if the bolts of the knees and legs are round enough or if you need to remove supporting material here as well with a sharp knife.
Step 3: Connecting the Printed Parts
Use slightly force to push the legs into the knees and the knees into the foods. It should be all able to move easily.
The servos should fit like shown in the pictures and can be connected with the whole corpus with the screws you will get with every servo. You don't need the connectors that come with the servos. Just press the servo slightly in the holes.
To get a good result and not much trouble when you try to let him walk you need to check that the servos are in the same position. Just roll the small wheel of the servo to the end of his motion range and than place the servos in the same position in the robot corpus.
Step 4: Wiring
As you can see in the pictures i used a arduino with pre soldered pins - don't do the same mistake! Use a arduino nano without these pins and just the holes. Its easier to solder everything.
I didn't needed extra wires because the wires of the servo are so long you can use just 3/4 of them (I used a bit less but its much more uncomplicated).
Solder first the wires of the control ports and in the last step the 5V+ and GND!
I used the cuttings from the servo wires to connect the HC-SR04 properly with the board and secured everything with shrinking tubes.
You can see on the pictures how i connected the switch. I didn't attached him to the corpus of the robot but with a bit of glue its easily done.
For the 5V and GND port you can make the following. Just connect all five cables to one cable (as shown in the pictures) and secure everything with a shrink tube. The one cable will be connected to the GND/5V port.
To connect the arduino and the ultrasonic sensor i just used some wire and the holes on the corpus.
Take your time.
Step 5: Let Him Move
You can see here some examples what you can do with him.
If you try to let him walk be aware. He needs to make small steps and need a super flat ground!
For example I just let him make steps in a range of 10-15° but maybe you will find a better way?!
Step 6: How to Use Him for Education
To use him for education you have plenty of options.
I made all the testings/code with a scretch like tool that's called ArduBlock. Its a good way to start.
You can give the kids the code how he can walk and let them explore how it walks or just start to let them move the arms and later let the arms stop/go in connection with the ultrasonic sensor.
Let them find a way to make the robot move/walk and compare in the class whats benefits of each solution or make a race.
I guess its too complicated to build the whole robot with the class but the basic setup and how a servo motor and a ultrasonic sensor work could be a topic as well. The kids can research where these parts are used as well.
Or you go deeper in coding and discuss how loops and conditions work...
You see here are a lot of options to go.
Step 7: Just a Small Step for the Robot...
...but a big step for me.
As you can see in the picture it was (is) a process. It was fun to make the robot and I hope he can be useful for someone else as well.
I guess it wont be the last robot I made and for sure the way he walks/moves is not totally satisfying.