The use of cellular networks has increased a lot over the past decade especially because now not only we are using to call people (the old fashion way) but also to do many other things like sending emails, photos, listen to music or watching movies. There are over 280 million mobile lines in Brazil but unfortunately prices for the service are still expensive, specially for data what makes over 3 quarters of lines be pre-paid ones. Although coverage is quite reasonable, we also have the same problem like any other country: Battery life! On average, a smart phone battery last for about 5~8 hours on regular use, not enough for the whole day.
The models were equipped with a 135w photovoltaic systems to power 6 USB ports (5V 1A) and 2 wireless charging pads. Besides providing power to charge many devices the electric system was able to sustain the LTE connection for up to 30 wi-fi enable gadgets at the same time. One the park ones we also added a small weather station based on a open source project to provide data about air quality to the city hall.
We had to come up with two different designs: One robust enough to stay outside on city parks, resisting thru weather (and maybe some vandalism too). The other one, lightweight and smaller to be installed on schools / universities, common private areas and food courts.