The human body consumes merely ~2000 calories a day. Really not that much energy, about the same as a 100W light bulb. Even if you can capture every single bit

The human body consumes merely ~2000 calories a day. Really not that much energy, about the same as a 100W light bulb. Even if you can capture every single bit of extra energy from a tshirt, you'd end up with a tiny fraction of 100W. Certainly not enough to power a mobile device like this.