Week 4

Progress

This week the block diagram for the initial electrical system was finalized, and a schematic was created. These can be found under the Design page, in the Electrical section. The picture below shows a prototype of the electrical system that was built, and used to test code for the robot. Currently the system utilizes a start button to trigger an interrupt on the microcontroller indicating that the robot's turn has started. The microcontroller then signals the robot arm height stepper motor to raise the robot's arm, and then the robot's arm length stepper motor extends the arm. A button is then used to symbolize the IR break beam sensor input, which will signal if there is a block to clamp. The signal from the button (IR break beam sensor) then triggers an interrupt on the microcontroller that will signal for the clamp to close, then signal the robot arm to return to the team's area, and finally signal the clamp stepper motor to release the block.

Challenges

I found out during my testing last week that my L298N H-Bridge motor drivers weren't sufficient enough to power the NEMA 17, and NEMA 23 stepper motors that control the robot arm's length and height. The L298N can only handle 2A continuous, but the NEMA 23 motor pulls up to 4A, and the NEMA 17 2A. A 160W Microstep motor driver was consequently purchased to drive the NEMA 17, and NEMA 23 stepper motors, because it can handle up to 3.5A continuous.

Action Items

• prototype of robot structure and arm
• prototype of stepper motor MXL pulley drive methods