Here are some examples of what I mean.
Nerg Box turned Time Travel box
In Book 1 In Times Passed, Brent stumbles upon a means to travel in time. He alters a standard issue Nerg Box which results in a machine that can jump a person back in time. This is all very well, but to have staying power, this device needs to evolve, develop in use, performance and even appearance. It starts out as a rather non-descript gray box (Nerg [eN ER Gy]) which provides a temporary means to increase stamina and attention span and is nonnarcotic. With some modifications in frequency and duration of the "effect," Brent finds he has created a means to travel in time.
But Brent and his friends are tinkerers, and they have access to a computer with extensive abilities to improve this early model. And Brent is not one to have a means to travel in time and leave it sitting in a closet.
Time Travel box turned Jump Stage
With Ismar's help, Brent, Jove and Quixote build a stage that has the same "effect" and can be used to concentrate the time jumping abilities to more than one individual or thing. This stage makes its debut in In Times Passed, and shows up again in No-Time Like the Present (Book 2) where it evolves over the course of the novel.
Jump Stage turned Jump Pack
In the third book, currently in redraft, Next Time We Meet, Mick and Emily find they can go anywhere or when for a second honeymoon by use of the individual, portable Jump Pack. It has somewhat limited capabilities in that the jump calculations must occur in the lab still, but once downloaded to the pack, those calculations are available no matter where the jumper is. This is important as they are on a honeymoon which is serving double duty. Mick has determined he is going to be a detective, with his wife Emily's assistance, of course. Every man, even one who can travel in time, cannot manage without a good woman by his side or ahead of him.
Jump Pack evolves some more
Book 4, with the working title of Testing Time, is in draft and makes extensive use of a more advanced model of the Jump Pack as it is able to calculate new jumps without returning to the lab. When things aren't going according to plan, such an improved model has tremendous advantage even if all it can offer is moving to another site to provide a few more seconds to make a dash for safety.
This item shows up for the first time in Book 2. It is a device that offers environmental as well as background information to its possessor. It is referred to and used once, but the question of its further use is asked and answered. It is appears again but as an embedded tool, one casually in use.
Schemslide turned essential time travel resource
In Book 3, Mick and Emily cannot manage without it. Now called the noter, it provides historical information, a filing system for notes, is the transfer unit for calculated jumps, records environmental features, and is a time-delayed communications device. Emily gets quite proficient at accessing its valuable capabilities as the travelers stretch their ability to understand the intricacies of moving about in time while tracking down a possible kidnap victim.
Readers complain about those "in the nick of time" devices or theories that save the day. I don't want that kind of situation in my books cropping up. What fiction devices, good or bad, have caught your attention?
Book 1, In Times Passed at Smashwords and Amazon
Book 2, No-Time like the Present at Smashwords and Amazon