I like those old articulating arm lamps. I've made several things from them but they have one major draw back and that is that if you have anything heavier than a lightbulb at the end they can't hold the weight. The reason is that there is just not enough friction on the pieces.
My redesign changes that by making disks from wood, thereby increasing the surface area thereby increasing the friction. But even then, wood doesn't deliver the required friction so rubber pads are needed. I used tool drawer liner. It worked better than expected because I don't have to really reef on the knobs to keep the arm in place.
I may make something that looks less like a prototype and more 'pretty' but it works so well, for now I'm just enjoying the fact that I don't drop my tablet while nodding off to sleep.