I don't know, I don't have a 3D printer. I can't imagine the reed switch needs to be positioned too perfectly as they generally work from a reasonable distance.
That is the rub. You know it is so simple, but want to be sure, to have the optimum location.
I tried to get one X-Rayed for non destructive analysis. No dentists I know would come to the party as they didn't know what settings to put on their machine and risk it. Maybe acetone destructive bath with careful and frequent observation might be an alternative, as it can't be that expensive to manufacture a plastic blob that encloses one cheap reed switch, one resistor, one stainless steel screw, and two/three/four wires of a meter or two.
I see a business opportunity for some Chinese individual to offer a cheaper part on Ali Express that is the same shape and functionality but far cheaper, similar to most 'genuine' car parts, made in bulk at the same Chinese factory, have a significant markup by the time they are handed over at your car dealer spare parts counter, but can be purchased direct from the manufacturer at significant cost differential. Even a writeup on Silicon Chip would instanrly kill the greedy markups demanded if people could roll their own.
A retail price of say $14.99 would be tolerable for something that contains a retail price of say $3 of parts to manufacture. Even a $59.95 trade price charged by Reece Plumbing is just outrageous, but they are just passing on the price the vendor thinks the market will bear.
Competition would bring it down to something reasonable. It is not patentable, just rare.
An ideal project for a hobbyist to earn part time cash to sell on eBay, or a high school/university reverse engineering exercise?
The TT110 pulse sensor used to be cheaper but since the corporate takeover of Elster by Honeywell, prices seem to have skyrocketed.
I did not end up buying the TT110 for $100+, I ordered a cheaper transducer from Aliexpress and will try my luck. Once received and installed I'll report the results in this forum.
Yes, with Honeywell you are paying a significant markup for the name as well as reputation, support, and distribution infrastructure involved.
Yes, sometimes you need healthy competition to keep large monopolies honest too.
I'd be interested in your R&D efforts too, and how reliable your Aliexpress device turns out to be.
Given there are a number of common meters used by Australian utility companies, each using the same magnet/reed switch methodology, there appears to be a money making opportunity just begging to exploit.
The startup R&D costs will be the most significant part, and the ongoing assembly, postage and 3D printing consumables should be a fixed component that will keep it going as a paying hobby style exercise.