Wiring, coding and testing the thermal printer. Your donation is a tax write off so save your receipt! When you finish taking the citizenship test you will be presented with a printed receipt that shows how many questions you answered correctly and the amount of money you donated to the Wounded Warrior Project.
I built this little contraption to test the weight limit of the stepper motor. My donation box will accept bills and coins so I need to know if the motor can hold position when multiple coins are added. This stepper motor and pulley system allows me to move the axis of rotation to the center of the box which is critical since the lid will need to tilt inside the acrylic canister with very little tolerance for forward / backward movement.
The donation lid will sit on the top of the donation box and rotate to open and close the donation slot. I'm now testing stepper motors instead of servos. Steppers allow for controlled movement but they can't store position data like a servo motor. If someone disrupts the movement of the lid the motor will stall and there is no easy way to "reset" the position of the motor.