Brainstorming process:

During the brainstorming process of creating a behbot, I was thinking of how to create 2 different movements to represent 2 different emotions. For the 1st sketch, I was thinking of the clock mechanism movement (grandfather clock) which gives people 2 kinds of emotions. When the minute hand of the clock goes fast which makes one anxious and if it goes slow it will cause one to be irritated.

I was thinking of how to implement the pull and push motion for the clock mechanism to work. I was thinking to have the servos move to the right at the same time with strings attached to the stick and the servos. As to how to attach the strings to make it look like a pendulum movement of the grandfather clock, I have no clue. Hence, I thought of the 2nd idea which was easier to implement.

Sketch 1 (image below):


For 2nd sketch, I thought of drumsticks after hearing someone playing drums. The speed of the sticks could represent 2 different emotions. I was thinking that if the sticks move faster it could represent angry while slow movement could represent fear or sad. 

I was thinking how I could replicate the movement of the drumsticks when someone is playing the drums through the use of servos. The servos just needed to move from 0 degrees to 90 degrees. 1 of the movement should be fast and strong while the other is slow and not too strong. 

Sketch 2 (image below):

Mockup (physical): 

Since I wanted to have a material that is similar to drumsticks, I decided to use chopsticks. I tried to mimic the movement and moving it at different speed to see if they have the effect I wanted. After testing and being satisfied with the outcome, the next steps I need to think about was how am I going to attach the chopsticks to the servos.

Prototype:

The first testing was with one servo. I wanted the servo to move from 0 degrees to 90 degrees instead of the usual 180 degrees. The servo went the way I wanted without the button pressing. Next, I had to implement the button to change the speed of the servo. After 1 servo with the button works, I added the other servo to see if 1 button could control 2 servos. 

After the servos worked, I attached the chopstick to 1 servo since there will be added weight needed to move the servo. The servo moved slightly slower which I had expected. Not only that, the strings tying the servo and chopstick becomes more loose as it turns. I realised that I had to make a ‘X’ figure in the middle to make it tighter. The strings did not become so loose as compared to the previous time. I used the same method on the other servo and chopstick.

Final:

For the final, I decided to make a stand to hold the servos. The panel on each side seems like hands holding on to the sticks and hitting the middle part (some sort of a drum).

Challenges:

The part which is the most challenging is coding the button pressed to change the speed. It is easy to verbalise it out but when it comes to adding 2 delays I have a problem with implementing it. After much testing, I managed to figure it out. When pressed once the servos will move at a fast pace and when the button is pressed the 2nd time, the servos move at a slower pace.

The other challenge is figuring out the position of the servos. I wanted to make them hit at a different timing instead of being simultaneously. I had to change the white part a few times before getting it to the position I wanted.

Final documentation: