Retractable USB cables!

retrolefty:

liudr:
Just be careful with these cords around transformers and halogen lamp bases(transformer inside). The cables don't have shielding thus the softness. You turn on or off a transformer or desk lamp, they knock out the USB connection. My desklamp does that to my mouse and keyboard every time. I wish I had more space.

I can allude to that also. I have a nice halogen desk lamp that swivels around for close in work. If I turn it on with any radio near (AM, ham radio, etc) it creates a large noise level making radio reception almost impossible. I haven't researched why halogen lamps do that, anyone know or have a fix?

Lefty

I busted one halogen desk lamp open and found a largish transformer, possibly to lower the voltage to around 12V for proper operation. You turn on a transformer and it is destined to leak out magnetic field lines from imperfect packaging and the quickly time-varying B-field will induce voltage across any wires nearby. If you have a grounded enclosure or shield, then this voltage is not generated on anything inside the grounded enclosure. Other lamp bulbs operate at 110V/220V and don't need transformers so they're not generating any interference with B-fields.

BTW, I made a photo gate flexible mount out of the deadn halogen desk lamp and kept the transformer so don't worry about wastes.

Here's the orphaned webpage I once wrote:

http://web/zliu/photogate/photogate%20homepage.htm