Little Bird Automates Stock-Picking with Bishop, a Raspberry Pi-Powered Raspberry Pi Picker

In a textbook case of "dogfooding," Australian electronics retailer Little Bird Electronics has made picking and shipping Raspberry Pi single-board computers and other gadgets significantly more streamlined — by using a Raspberry Pi to automate the process.

"Bishop is our Raspberry Pi-powered picking (and eventually packing) robot," the company explains of the automation system, which has been put to work in its Pi Australia division. "Named after the android in the movie Aliens, Bishop consists of a shelf and a shuttle that moves along it to pick order line items and deliver them to a pick bin. It is kinda like a giant vending machine for our most popular products."

The Bishop system, developed by Little Bird and Nuvotion's Nick Owen, is powered by a Raspberry Pi 4 Model B 4GB, one of the very products it's designed to pick for shipping, running the Raspberry Pi OS Linux distribution with LinuxCNC and a Mesanet 7C80 FPGA_based automation controller for computer numeric control (CNC) of the stepper motors and linear actuator that drive the mechanical side.

That mechanical side is put together using a customized plywood and steel shelving system to hold the stock, a rack-and-pinion for the shuttle, and a combination of Hall-effect sensors and limit switches to determine the position of the shuttle. When a product has been ordered, the shuttle finds its location, moves towards the shelf using a linear actuator, lifts the product over the shelf's lip using a "finger" inspired by a toy train, and delivers it to the packing area.

"When an order comes in from one of our sites, the Rails application [Koi, an inventory management tool] assesses whether Bishop has the products that are required to fulfil the order," the team explains. "If Bishop has the products, it will then send a request to a Ruby script running on the Pi to pick the products. The Ruby script then connects to the LinuxCNC's linuxcncrsh process via Telnet and sends a series of commands to LinuxCNC to pick the products and deliver them to a picking bin."

While Bishop works as-is, the Little Bird team is testing out a few potential upgrades — including automated packing and labeling for shipping, the latter including experiments with the use of reusable shipping boxes with ePaper labels supporting remote refreshing. "Don't tell Auspost this," the team writes, "but we've tested their ability to scan and deliver the E Ink label, and it works!"

More information on Bishop is available in Little Bird's blog post.