What does civic frustration look like when combined with technical know-how? In Philadelphia, it has resulted in a sort of guerrilla network of solar-powered e-paper signs showing how often buses arrive, constructed not by the city’s transit authority, but by mysterious artists armed with microcontrollers.
The ESP32 is the backbone of this project and is a microcontroller with WiFi and Bluetooth capabilities, which is very small and powerful. This microcontroller is the central controlling unit for each sign and receives the real-time arrival information from the public data feed offered by SEPTA, the same data used for the Google Maps transit information, and displays it on the low-power e-paper displays. The use of e-paper, which is commonly known as an e-book, helps the system save considerable amounts of power, as it is able to retain an image even when there is no power connected to it.
The solar panels are installed to maximize the exposure to sunlight, connecting the charges to water-resistant housing units containing the electronic components. The units are designed for resistance against the rain, snow, and temperature variations for continued functionality irrespective of the climatic conditions in the City of Philadelphia. The design is carefully spaced, choosing the intersections based on their significance to the participating artists. It is a combination of functionality and public art, with the metallic signs designed with images depicting birds and flowers, indicating the arrival times of the bus for anyone who cares to take a look.
‘Make it Weird, the pseudonymous lead artist, called the process “months of problem-solving, research, and trial and error.” The team focused on reducing power consumption without reducing clarity and reliability. The team’s concern for power efficiency aligns with the best practices for solar-powered IoT devices intended for the infrastructure of a city with limited power resources and maintenance access to the devices.’
The project has as much civic need as technical support. Philadelphia’s Southeastern Pennsylvania Transportation Authority entered into a five-year, $6 million deal with a new company in 2024 to install as many as 700 real digital bus-time signs, but none have yet been put out. Cybersecurity testing of a possible new provider has been given as one reason for this, and a growing budget crisis, currently down $231 million this year, has further hindered implementation. The agency cut back service by 20% in August, reducing or cutting altogether 32 bus routes, with many others operating less frequently, mainly impacting passengers without smartphones and data plans.
For these cyclists, the guerrilla media installation is far more than an interesting novelty. In fact, as one cyclist, Brianna Brooks, stated, “When it’s cold you want to know how long it’s going to take without taking out your phone… Now you know.” This immediate, glance-and-go functionality was only possible in New York or Minneapolis but not in Philadelphia.
There are also independent participants in this space. Max Goldberg, a creative director, began with a hacked sports timer to display bus arrival information and eventually developed the ESP32-controlled scrolling message display mounted inside his apartment window to face the bus stop. These examples show how versatile displays for public transit information can be, starting with home brews from consumer items and increasing to designed models as expertise and resources increase.
Both Goldberg’s and Make it Weird’s projects have the intention of releasing their code into the public domain in order for a replicate set of these phenomena to be identified elsewhere in other cities. Infrastructure of this kind, developed in the open source manner, could very well help to push through a grassroots movement for DIY transit technology based on free public data feeds and low-cost components to help fill the service deficit. The system is simple: a data-retrieval script executes on the ESP32, interpreting routes and times of arrival, and updating the e-paper display periodically.
Power control routines control solar recharging and the use of the battery to guarantee continued operation during periods of sustained cloudy weather. Engineering-wise, these signs show how low-cost, embedded systems can benefit the community utilizing data and come together in a cost-effective, beneficial way for the public. Moreover, these signs demonstrate how independent, grassroots systems can thrive despite the delay of their institutional counterparts. As SEPTA’s institutional initiative continues to be stagnant, these artist-engineers have managed to create their own functional system, independent and successful.
