Typewriters can be an interesting poetry topic idea for many reasons. For the purpose of this poetry topic idea, a typewriter is not electric, but is only mechanical.
The first reason, is the idea that a typewriter is a complicated mechanical device. A typewriter is in some sense “busy”. There are moving parts that interconnect in a series of actions. There is a certain sense of complicatedness to it. The idea of this complicatedness and interaction could be the basis of a poem.
Secondly, a typewriter is in some sense antiquated. It is not normally used today. It has been replaced and is in some way obsolete. All of these ideas, antiquatedness, replacement and obsolescence, could be poetry ideas.
Thirdly, depending on the individual, some people may have direct experience with a typewriter and some may not. The idea of these differentiated experiences, the idea of knowing about something and not knowing about something, could lead to a poem. In a side sense, it could be interesting to compare poems about typewriters written by people who have direct experience with them and those who do not.
A fourth idea from typewriters is the idea of an irrevocable mistake. On an old typewriter, if a mistake was made, there was no way to correct it without affecting the final piece of paper. Once a mistake was made, the idea that the final piece of paper, could in some way be pristine, was lost. This idea of irrevocable mistakes could lead to many poems.