I would say she is feeling neglected and that you spend more time with your projects than with her. It could be several things or a combination of them.
1. You actually are spending much more time with your projects than her (neglecting her).
A. Spend more time with her. Just sitting in the same room with her while playing around with electronics probably won't cut it. You need real quality time (and not just sex).
2. She is jealous because you have a time-consuming hobby and she doesn't.
A. Help her find a hobby. Work with her, especially at first. Help her set up her "work area" and show a real interest in what is wants to do.
3. She feels that you did something to her and this is payback.
A. Once again, sit down and talk about it. Apologize to her.
4. There are some more serious feelings that she has been tucking away for a while and they are starting to leak out.
A. Try to communicate more, spend more time together, and maybe see a marriage counselor.
Although our society tells us to blame others first, a lot of times it can be partially or totally our own fault. Don't be so quick to say she is the one that needs to change.
I'm not trying to come off wise or arrogant, just trying to help. Marriage is a precious thing. Work hard to save it. If you don't like or agree with my comments, please ignore them.