There are plenty of decent sources of entropy, like webcams and sound cards. However, they all add parts we don't need, and they don't take any care to design with security in mind. Eventually, a good open hardware TRNG should be cheaper, more reliable, easier to use, and more secure than any of those solutions, IMO.
What are you worried about exactly? Space? There are really really tiny cameras for smartphones that are mass-produced, and they are very noisy, which is perfect.
