Could this be The Hummingbird Series by <PERSON> - you can read/get it free on Smashwords. This series tells the tale of a range of people, but initially of a girl created/bred as part of a military research project, who is an autistic savant, capable of advanced mathematics and incredible feats of engineering at a very young age. She goes on to create a number of things, including an AI inside a very advanced fighter-jet and some other similar items.
The following is a summary of the series as I remember it, I'd not be surprised if I have something wrong:
The girl is brought up in a brutal military selective program where she is part of a group of created/bred people who are selected for intelligence and ability, far beyond what you would expect from children. They are aim is to get them to create new military concepts/weapons etc. At some points in this system she is starved, raped (by another competitor, who she later kills), beaten, bullied etc, unnecessarily to the story in my opinion.
She creates/designs a bunch of things, among them being a termite farm as a food source, potatoes and corn that are drought tolerant. 44
She also creates an AI, which she stores in an optical/quantum computer in a ring that she disguises the manufacture of by making at the same time as making some highly advanced armor/fighting suit and as a part of that also making a highly advanced energy storage device. The plans she creates for these are cryptic and deliberately misleading so that she can use the information as bargaining leverage against those in power. Because of the energy storage device, the people in command make a bunker system containing a larger scale version of it and some sort of self-contained community.
She later makes an advanced fighter-jet incorporating the AI (IIRC using the large scale device, which she predicted would be made by those in charge), but makes it only respond to her. She is then pressured to release the technology of the AI and fighter she created and does so under some stringent conditions, which basically allow her and her friends to go to war against a group of foreigners (IIRC led by an immortal/golem type figure, probably in the Middle East), and have some freedom from the restrictive military regime she has been under. She and her colleagues in the fighters are shot down somehow (EMP??, perhaps the immortal does something) and captured, which triggers her AI to create a world-ending scenario that somehow ends with metal being unusable (induces very strong electric current IIRC), and causes a major population crash etc.
I think the story then jumps in time and follows the lives of two individuals struggling to live following the population crash, who set about creating their lives in the absence of metal, using material derived from plants (I think milkweed), using latex and fibers from the plant to create structures, clothing and a range of mechanical devices, including a long-distance signalling system based on semaphore or flashing lights. I'm not sure if a fan powered by a pulley system is one of these, but similar things are made.
The cover-art features a teddy bear with one-eye as a X shape, which may be what you remember. 999