Four streams, one platform.
A four-module design accommodated wine bottles, mason jars, yogurt tubs, and cans. Its conveyor-based architecture established the first complete return system.
← All projectsMaking reuse
Industry project · Circulr · 2024–2026
Making reuse
returnable.
A compact reverse vending machine that accepts reusable containers and turns each return into a grocery-store reward.
Circulr Reverse Vending MachineDesigned, built, programmed, and tested by Aaron Emmanuel.
See the return experience ↓
OwnershipConcept to deployment
FocusMechanics + electronics + software
In-store deploymentOctober 2025
The challenge
Make container returns part of the everyday shop.
Circulr needed a practical way for customers to return reusable packaging in a grocery store. The machine had to validate each return, handle containers carefully, and issue a reward through a straightforward customer interaction.
As the sole engineer building the system, I connected mechanical design, electrical integration, software, fabrication, and testing into one working product.
01 / The return experience
Scan. Return.
Get rewarded.
A guided transaction connects a physical container to a validated refund, with the machine checking the handoff along the way.
- 01
Start
A button begins the return session.
- 02
Scan
The Raspberry Pi checks the barcode against a locally stored list of accepted containers.
- 03
Return
An approved scan unlocks the return gate. Distance sensors monitor the handoff and flag removal or substitution.
- 04
Finish
One printed receipt totals the accepted returns, ready to redeem as a grocery-store discount.
02 / Product evolution
Smaller footprint.
A more focused machine.
The first system explored four return streams. Store feedback and return patterns shaped a simpler, single-module product centered on jars and cans.
Built around the most common returns.
A compact single-module machine reduced the footprint and number of mechanisms. Focusing on jars and cans simplified the return path and made the customer interaction quicker.
03 / Engineering the product
One machine.
Connected disciplines.
Handle reusable containers carefully.
Chute geometry and cushioning were refined through rapid prototypes and repeated testing. The aim was a reliable slide into storage without sticking or damaging glass containers.
Build with proven components.
Off-the-shelf sensors, servo motors, a barcode scanner, and a receipt printer were integrated around a Raspberry Pi. Component choices prioritized cost, availability, and speed to market.
Validate the whole transaction.
Python software manages the approved-barcode list, gate behavior, sensor feedback, item values, and receipt total. A rejected barcode leaves the gate locked; a detected handoff error excludes that item from the refund.
Recover without a manual restart.
Automatic startup, watchdog monitoring, and timeout-triggered restarts were added to address observed software failures and support unattended operation in the store.
04 / Tested performance
Validated at the item and system level.
6 + canssupported mason-jar SKUs plus aluminum cans
100%identification of supported items in testing
100%rejection of tested unsupported containers
~1 sprocessing time per item
40%under the approved project budget
05 / In the real world
From the workshop
to Fiesta Farms.
In-store testing began at Fiesta Farms in Toronto in September 2025, followed by customer deployment in October. Circulr recorded the last reported issue in March 2026, followed by six months without a reported failure.
Identification, rejection, and processing results were recorded during project testing. The six-month operational update was reported by Circulr and is not an independently measured uptime statistic.
June 2024 – August 2025Full-time technical lead
Design, integration, build, software development, and testing.
September 2025Initial in-store testing
Single-module RVM installed and tested at Fiesta Farms.
October 2025Customer deployment
The return experience entered customer operation.
Through June 2026Continued development and support
Part-time work as an independent contractor following the full-time role.
Designed & built
Aaron Emmanuel · Sole technical lead