What we created

We created a bar graph using foam core, a stepper motor with a driver, neopixel strips, a lead screw mechanism through the use of a threaded rod and a bolt.

We also created a cup sleeve using foam core, neopixels, and an RFID tag embedded in the body.

The RFID tag was read using an RFID reader which was a separate installation.

Methods and techniques we used

Considering the dimensions and weight of the bar graph, we used a NEMA-17 size bipolar stepper motor with 200 steps/rev, which runs on a 12V power supply. To run the motor, the A4988 driver was used. The lead screw mechanism was designed using a 12” long, ¼” threaded rod with 20 TPI(threads per inch) and corresponding nut. By driving the threaded rod with the motor and constraining the nut, the bar was moved vertically both ways. Each bar consisted of a neopixel strip which was connected to a 5V power supply. The motor and the neopixel for the bar graph was controlled using particle argon.

For the sleeve, a neopixel strip and a neopixel ring were installed and controlled by another particle argon. Also, an RFID coil was stuck to the sleeve. To read the same at the store counter, a reader was designed with an RFID RC522 board which was controlled by the third particle argon.