Many everyday tasks still rely on outdated systems, like using physical coins to unlock shopping trolleys. While small, this inconvenience affects millions of shoppers who no longer carry change, creating unnecessary friction in an increasingly cashless world. Retailers also face hidden costs managing coin inventories and abandoned trolleys.

A Digital Solution for Trolley Access

One way to solve this would be to create a universal mobile app that replaces coins with digital deposits. Here's how it might function:

• Users scan a QR code or tap an NFC tag on the trolley to place a temporary hold on their account (typically €1-2)
• The hold is released automatically when the trolley is returned to its dock or manually via a "return" scan
• Retailers could retrofit existing trolleys with inexpensive QR stickers or upgrade to smart locks over time

The system could work across supermarkets, airports, and other locations with coin-operated trolleys, removing the need to download multiple retailer-specific apps. Additional features might include family accounts for shared use or integration with loyalty programs.

Benefits for Stakeholders

This approach could create value for multiple groups:

• Shoppers: No more searching for coins, especially helpful for younger users and tourists
• Retailers: Reduced coin handling costs and fewer abandoned trolleys cluttering parking lots
• App operators: Potential revenue from small transaction fees or retailer partnerships

Supermarkets might be particularly interested if shown data on how coin requirements lead to abandoned trolleys or deter potential customers without change.

Implementation Approach

A practical way to test this concept would involve:

1. Starting with a basic version that works with QR codes at one test location
2. Expanding to a small retail chain to prove the concept works at scale
3. Gradually adding features like NFC support and integrating with different types of coin-operated systems

Early versions could use simple refundable payment holds rather than complex smart lock integrations, allowing for quick testing with minimal investment.

This concept builds on existing attempts like retailer-specific apps or prepaid cards, but offers a more universal solution that could eventually become standard across multiple use cases, from grocery stores to airport luggage carts.