The authorities of the city of San Marcos (Mexico) have a project to develop the municipality as a smart and sustainable place. This requires funding, technology, and expertise that they scarcely have, since they are afflicted by digital exclusion. To face the challenge, they are using low-cost technologies with optimised deployments to minimise maintenance and environmental costs. They are also relying on open science and knowledge transfer. They have agreements with Unijuí University, the city of Santa Rosa (Brazil), and collaboration with the University of Cambridge (United Kingdom). This paper discusses the main technical problems, technology used, and results already achieved and outstanding.