Yea, I had one thing I made after re-designing the whole thing when they were not made any more, My Fur-FindR unit
Early 80's had my last one stolen that Ed Courtny used to make, but the market fell off due to low fur sales, I could not find one in any trapping store or fur place, so I made my own, took me a year to get it how I wanted it, worked very well, sold a few then a few more then a stampede of more. Did not even have animal sounds on the first unit, still brought in fur !
Had to start over again after the part I use was no longer made, changed things around, made it better, louder with animal sounds on it, same thing it took off as the fur market did a bit and I was in business once again, until some thief decide to copy it and try and give me competition with my own design in a new container, never did take off for them.
Then I had to change again with more updated stuff that users had suggested they wanted, same story because the other units worked so well this one took off until last December, when the chip used on it reached end of life !
I've finished working on a new one once again and updated things, added some ideas, changed the container a bit and will be selling by mid August, now fully retired so I can work to make sure I don't have to back order, got a new credit pay established because people were asking to pay by card so much I was worried about losing them as buyers and users.
Been a great hobby money maker for me to save for hunting and it pays for the supplies pretty much as well, I get great satisfaction of people sending me pics and vids of their catch's and the unit now has found other use's in research, and biology studies by government workers, as well as trail camera people, the units have sold all over the world and people still send pics because they like the units so well, can't get any better than that, from not having one to use to building thousands of them over the last 25 years or so to so many people , If one thing I did right in my life besides my wife, it was taking the time to follow a dream of making a tool that I needed for my own fur trapping !!!