Here is a picture and video of the robot:
This robot consists of:
1 EV3 Brick
2 Large Motors
1 Ultrasonic Sensor
This robot was harder to build than originally expected. At first, one motor was used to push down the handle. This idea did not work. After many trials and failures, the L3GoBots Lady (link to her blog here) suggested a brilliant idea. One, that the robot use the power of two motors instead of one. Plus, the dispenser should pull down the handle instead of pushing down the pump for maximum force.
Below is a picture of the pulling mechanism:
A Steering Link and tow ball with pin is used to pull down the handle. The Link attaches to one of the holes on the motor instead of the middle of the motor where the axle hole is located.
Here are pictures of the steering link and tow ball pin:
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Steering Link (Top) and Tow Ball Pin (Bottom)
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The steering link and tow ball pin when they are connected
The entire program is placed within an unlimited loop block. First, it resets both motor B and C. Then, the program WAITS for someone to place their hand above the ultrasonic sensor. The robot will then say "Place your hand about an inch below the handle. Wait for hand sanitizer." After waiting for 0.2 seconds, the large motors will then pull down the hand sanitizer pump, allowing the hand sanitizer fluid to fall into waiting hands. The robot instructs the user to remove their hands from beneath the pump. It then politely sends them off by saying "Thank you! Good bye and have a nice day!" Afterwards, a wait block is used for 3 seconds.
A picture of the program is shown below. It was broken up into two pieces to make it easier to read.
Below are the links to buy all the materials listed in this article.
EV3 Home Edition Kit
Ultrasonic Sensor
Here is the link to download the EV3 Home Edition Programming Software:
EV3 Home Edition Programming Software
Happy Building!
