The Mini Temp Logger v1.0 has now been released and is available for purchase.
This project has quite a few SMD parts, soldering them by hand can take a long time so I decided to give stencils a go as I hadn’t used them before. I ordered one from OSHStencils for the top side, it came within 1-2 weeks which was good. I played around with how to align the stencil, applying the solder paste, etc, after a few tries I got relatively good coverage of the pads, placed the components, soldered them with the hot-air rework station and it worked out nicely.
We also have a GUI now which automatically picks up the device so you can easily connect/disconnect them without closing and re-opening the program.
I built a few more of them up with two different RTC capacitors, 7pF and 8pF, both of them seemed to worked well and the 8pF one almost didn’t need any digital trimming. I popped them in the freezer but both of them eventually stopped working after a few hours so that’s no good so it’s back to the 6pF caps.
A quick comparison between 2 loggers (top) and 3 loggers (bottom – in freezer, something isn’t right with our freezer, pretty hot day when the test was run) placed right next to each other shows that temperatures between them were very close to each other so the TMP102 temperature sensor is pretty accurate.
Hi Alex,
very nice job! I’ve recived the thing recently and I’m thrilled! It works, is symply, straightforward and does what it should!
Many thanks and respect for you competence!
Best regards,
Oleg Ginovker