It's wonderful to hear from people making their own light hats. Keep them coming, and please send me photos to post on the blog. I love the creativity people bring to it.

Some important things to remember:

1. 12 volts only. No more than 12 volts, ever.

2. When you search for LED strips, and all the bibs and bobs needed, always choose the 12 volt versions.

3. My experience is that the visible red spectrum (especially 650-670nm) seems to be loved by cells anywhere in the body.

4. But the almost-visible near infrared 810-850nm wavelengths don't work for every neurodegenerative condition.

5. When in doubt, stick to the visible red, preferably a gorgeous dark red.