This project creates an hardware interface for the cash drawer with RJ12 connector. The interface is powered by a 24v DC power source. With a microcontroller and relay module, the cash drawer can be controlled by a customizable switch (which is also quick swappable for different needs). The builtin speaker module/port also provides audio feedback when opening the drawer. As well as a 3 pin JST connector that powers a 8x32 matrix display.

Supplies

24v DC power supply
DC connector
5v relay module
24v to 5v step down module
8x32 LED matrix grid
Mini Speaker
3.5mm audio connector (female)
Circuit Playground Bluefruit (microcontroller)
Cash drawer with RJ12 Interface
Cardboard
Ice-cream sticks
Glue Gun
Wire
Tape

Step 1: The Design

This is the basic idea behind the design, major component listed

Step 2: Reference Material

this is the interface for the cash drawer connector, we will need to use the two wires labeled "coils" to trigger the drawer lock

Step 3: Schematic Design

Follow this design step to put together the control interface

Step 4: Connection

Connect all components as described above, use ice-cream sticks as needed to reinforce the connectors. Hot glue or tapes to secure the parts.

Step 5: Add Magnets

Finish the enclosure, and tape some magnets for easy attach and detach from the drawer.

Step 6: Program the Board

Upload the code.py program to the circuit playground Bluefruit, and also download the audio files to the board

Step 7: Finished!

Give your control interface a nice looking color with the cardboard, and connect the RJ12 connector to the drawer, power everything on, and see it working!

Introduction: Smart Assistive Cash Drawer