A smart recycling bin needs to operate outdoors, without needing to be plugged in, in dirty environments, and with thousands of uses per month. Candam solved this problem with RecySmart, a ring that adapts to glass and packaging containers, and classifies each container using an acoustic sensor and artificial intelligence. In chapter 54 of “Toque de Ingenio,” Jordi Berguinzo explains why they abandoned computer vision, how they power the device, and what incentives they use to encourage public participation.
Guest: Jordi Berguinzo, who was introduced in the episode as a co-founder of Candam Technologies. Interview published: June 10, 2025. Episode: 54. Duration: 1 h 31 min.
In this episode:
- Why does an acoustic sensor perform better than a camera within an urban container/environment?
- How to feed and maintain a device that operates on the street without access to electricity.
- What incentives and what pace of implementation lead to citizen participation?
The conversation was recorded in the spring of 2025, with the new waste rate recently implemented and the deposit scheme for packaging scheduled to be introduced in Spain by the end of 2026.
Smart recycling container: making the most of what’s already on the street.
Jordi locates the origin of Candam within the deposit return system of Northern Europe. Machines in supermarkets use barcodes and optical sensors to identify the packaging and return the deposit. These machines have been in use for almost 30 years and perform their function effectively.
Their limits are defined by the Candam void. They require electricity, occupy space in retail, and primarily cover bottles and cans – accounting for approximately 30% of packaging. The European Commission is calling for a significant increase, aiming for 90% of packaging to be reused by 2029.
An alternative was to simplify that machine into a single device. RecySmart is a ring that is fitted into the opening of glass or lightweight packaging containers. The citizen identifies themselves using a card or an app, depositing one container at a time, and the system classifies the material in real-time.
The figure that justifies that decision can be found in the conversation: there are approximately 400,000 yellow containers and 250,000 glass containers in Spain. Jordi compares the device to an electricity or gas meter, but one for packaging.
Identifying packaging without cameras: acoustic and artificial intelligence.
The central technical question is how to determine what has been discarded. Computer vision was ruled out due to the environment. A municipal waste container accumulates dirt, and a camera stops working if it’s not cleaned regularly, which increases maintenance costs.
“Computer vision needs to see in order to classify”.
Jordi Berguinzo 14:22.
The team was looking for an affordable system that wouldn’t get dirty and could be enclosed in a protective IP67 casing against dust and water. Their solution involved combining acoustic technology, artificial intelligence algorithms, and a mechanical component within the device itself.
According to Jordi, a single sensor is used to classify plastic, cardboard, and ‘brik’, as well as metal and glass. The algorithm is configured based on the proportion of each type of container. At the time of the interview, the European patent was about to be granted, and another patent was being drafted, utilizing sensors that are not optical, for example, to distinguish PET from other plastics.
Choosing a sensor based on its suitability for the environment it will be used in, rather than solely on its accuracy in a laboratory setting, is a common practice in Electronic engineering For outdoor use.
Powering a device that lives on the street.
Jordi explains that they started with solar panels and rechargeable batteries, but they abandoned that approach due to their experience in the field. Each container has a different lid – some are oval, others are straight – and adapting the panels to each model proved to be a difficult and time-consuming process. Furthermore, the panels became dirty, some containers were located under trees with no sunlight, and vandalism caused them to be ripped out.
The decision was to switch to non-rechargeable lithium batteries, with a return process when they run out. Sudden temperature changes were also shortening the lifespan of the rechargeable batteries; Candam has installed them in the United Arab Emirates, where temperatures have reached 50°C in the summer.
The lifespan is measured in uses: the device can handle approximately 120,000 recycling cycles, and when inactive, it lasts nearly three years. Depending on the country, the actual number of uses will vary: in Spain, an average person can recycle 30 packages per month, while in Switzerland, it’s five.
According to Jordi, for local councils, what matters is the service provided. The industry standard is between eight months and a year – as with electronic billing – and Candam’s commitment is to replace the battery before any issue arises for the citizen.
Connecting with citizens: card, app, and data
The identification process is available through two methods. In the public sector, the use of NFC cards distributed by the local council or administrator is prevalent. Using the application, the mobile device connects to the device via low-energy Bluetooth, and data travels through the user’s phone.
That second option offers improved connectivity. Jordi explains that in Spain, there are many areas with no coverage where an IoT device never manages to connect. When data is transmitted via NB-IoT, it’s sent one or two times; however, when it’s transmitted via Bluetooth, it relies on a mobile phone. In their use cases, between 60 and 70% of interactions involve a mobile phone.
Personal data are held by the local council. Candam only sees identifiers – which he refers to as “registration codes” – and the materials deposited. The platform can be their own, or a third party’s, and some councils are requesting that the device be integrated into their own application.
Designing the incentive: waste rate, pay-per-generation scheme, and marketplace.
Technology only makes sense if the data is used for a purpose. Jordi explains that from April 2025, local councils must have a separate waste collection rate that covers a service which is currently inadequate and rewards those who recycle effectively. To offer these rewards, it will be necessary to know what each individual is recycling.
The system doesn’t weigh or read codes; it calculates deposits based on the amount. Once the rate has been implemented, the bonus will be added directly to the bill.
Edgar raises the user’s objection: depositing bottles one at a time takes a long time, and with a saving of 15 euros per year, many people will simply discard the entire bag through the other opening. Jordi responds that changing habits requires a sufficient incentive. The variable part of the rate can be 50% or 60%, and in Meliana, with local business vouchers, participation increased significantly.
For the private sector, Candam offers a dedicated container and a marketplace where campsites or petrol stations exchange packaging for discounts. That same marketplace is also used by local authorities to stimulate local commerce. Jordi, referring to initial data, mentioned increases of 15 to 20% in collection rates.
Introducing technology without causing resistance.
Edgar recounts the case of Premià de Mar, where the removal of all bins with cards resulted in bags being left on the streets and the formation of a local residents’ group. Jordi doesn’t specify the exact municipality, but he explains how Candam proposed its installations.
“When introducing new technology, it’s important to do so gradually.”
Jordi Berguinzo 1:12:45.
Their method consists of three parts. Firstly, starting with the glass, focusing solely on identification, and then moving on to packaging when the initial reception is positive. Secondly, a sustained communication campaign over several months, rather than just a few days. Thirdly, a technical design that doesn’t close anything that shouldn’t be closed.
That design has a logic: electronic closure in organic and cardboard, a glass ring and packaging, and an open container for waste. Anyone who participates receives a bonus; those who don’t can simply continue to throw things in and pay more. According to Jordi, closing the glass would actually worsen the quality, because the lid opens abruptly and allows unwanted items to enter.
In lightweight packaging, the issue lies with the bags themselves – approximately 30% of the contents are unsuitable. Therefore, the device occupies one of the two openings, leaving the other free. Jordi insists that no single technology can solve the problem on its own.
What can another development team learn?
The Candam case offers four key lessons for those designing devices installed in public spaces:
- Choosing the sensor based on the environment. A camera is precise in the lab; a sensor that doesn’t require cleaning can survive on the street.
- Design energy with maintenance in mind. A non-rechargeable battery with a programmed charging schedule can be more effective than a solar panel that isn’t protected.
- Utilize the user’s device. Sending the data via mobile saves on connectivity and addresses areas with no coverage.
- To schedule the implementation. Starting with a gradual change and communicating consistently over several months helps to avoid rejection.
At the time of the interview, Candam had approximately 700 devices installed and was working with local councils, waste management companies, and private businesses. The model combines the sale of the device with a software subscription per unit, and they are exploring rental options and plastic/carbon credits as potential future revenue streams.
In i-mas, we develop. products that incorporate sensors, low-power electronics, and mechanics to function outside of a controlled environment. If your device needs to operate on the street, in a factory, or in a vehicle Tell us about your project..
To continue reading: How are self-service car dealerships without staff for the street/outside being designed?.
Source of article: An interview with Edgar Guerrero on Toque de Ingenio with Jordi Berguinzo. The excerpts cited refer to the minute of the conversation. The project recommendations are a summarised editorial from i-mas.
