Quote Originally Posted by Robin Hewitt View Post
Is it possible they fit them to stainless because it is non-magnetic?

I remember, back in my days as digitizer tech support, the manufacturer accidentally printed a menu overlay for a capacitive tablet using conductive ink. Oops-Splatt :heehee:

I got the impression that the technology wasn't friendly if messed with.

Did you try insulating the scale then sticking a cap to ground to de-jitter it? They don't seem to bother much with decoupling.

Robin

There's about 1uF of inbuilt capacitor. The scale is powered all the time its just the display thats turned on and off, at least on these ones, so they read the same when you turn them on as when turned off... as long as you dont move them. I've seen a number of articles that suggest putting 100nF + 10uF when powered remotely and no battery in the compartment. I like Bill's idea of a local reader pcb and localising the power arrangement, that will get rid of many glitches. I've sketched a design using a small number of SMT parts that can be fitted to the existing reader PCB instead of the display case. I think a small bit of ali milled to suit will act as a suitable casing.

The existing case is definitely built down to a price. It took several attempts to get the display to work again after I dismantled it because the positioning of, and pressure on, the zebra connector seems to be critical. and the screw holes are marginal at best... in fact the 4 retaining screws for the PCB have all but one pulled through the pcb so i flowed a little solder in the holes to tighten them up.

I am debating whether to grind the calipery bits off or try to use them as a mount...

oh the other thought I had was making the PIC do calibration to improve accuracy over the long runs... some form of look up table of offsets per cm

and another thought: what about compensation for temperature? does the PCB expand enough to warrant it?