The Sliding Rail was constructed using a linear rail with a slider (single assembly usually used to make CNC lathes), two geared pulleys mounted on pulley shafts driven by a pulley belt. Pulleys were supported on either side by brackets which were mounted using screws to the base board as shown below. The robotic arm would eventually be mounted on the Slider.

Coupling between Bipolar motor and pulley shaft using a plastic tube.

Pulley positioning on board

Fully assembled pulley system top view

Fully assembled pulley system side view

[Failed attempts] This mechanism was arrived at after a few failures. Attempt one used a 4 Wheels based Platform on which the robotic arm was mounted but the wheels would not travel in a straight line which was critical for this to work. Even constraining the wheels to move along a guided path failed badly and accuracy was compromised.

Once the linear slide was aligned next to the belt, the robotic arm could be placed on the slide. The bipolar stepper motor was then coupled using a plastic pipe to one of the pulley shafts. The power of the Bipolar motor is transferred to the pulley shaft to control the belt's movement forward or backward. This allowed for a smooth backwards and forward motion for the robotic arm, as seen in the picture below.

After this, connect all three stepper motors to the Arduino along with the driver for the bipolar motor. See the Fritzing diagram for details on how to hook them up using the motor driver.

Here is a circuit diagram for the connections:

Industrial Security QA

This project creates a robotic "Badging Bot" designed to simulate thousands of badge-swipes to test the reliability of commercial access control systems.

• Servo-Driven Swipe Arm: An Arduino manages a high-torque MG995 servo that physically sweeps an RFID tag across a commercial reader. The firmware tracks the number of successful "Reads" vs "Timeouts."
• Variable Speed Stress-Test: The user can configure the "Swipe Speed" and "Interval" via the Serial Monitor (using Arduino IDE 2.0), allowing engineers to identify the system's performance limits.

Data Reporting

• Reliability Logging: The bot logs every failure to its internal memory. At the end of a 24-hour test, it provides a "Success Percentage" and identifies any mechanical or software lag in the security system.

Final working prototype:

Note: Although I have used an Arduino Mega in this project, an Arduino Uno can also be used.

Improvements:

1. Using wood for the robotic arm made it sturdier. This made it easier for the cards to be picked up and dropped off more accurately.
2. Introducing a cardboard card holder with diagonally cut sides allowed the cards to slide into the correct slot even if they are not placed correctly.
3. Using wifi, we can control the bot from anywhere. This will serve its true purpose allowing cards to be tested without having to be present.