My Goal: Reliably Monitor Temp/Humidity inside a Freezer (metal exterior case)
My Problem: There does seem to be a off the self product that is under $100.00 that can do what the Everspring ST-814 can do with either a wireless sensor or remote antenna that will work with a Vera 3. Currently I don’t have the time/knowledge to try and build a one-wire solution.
Question: I opened up the ST-814, and it appears to utilize a simple copper wire antenna. It looks to be about 10 guage solid wire. Would it be possible to solder on a wire and jack (jack to allow removal of the antenna to replace battery and such) to extend an flexible wire antenna through the boxes exterior walls?
I don’t know about your specific device, but if modifying the wire antenna, I think you need to make sure it is exactly the same length as the original (else it will adversely affect the radio frequency).
Ok so I did some testing today, and I can report the final antenna I ended up with seems to be working VERY well. I have never been able to poll the ST-814 while in the freezer and updates were slow and erratic. With this mod and can now poll, configure with the unit inside the freezer. The updates are much faster and seem more reliable.
NOTICE: What I DON’T know is if the modification is harmful in anyway to the device itself or to other devices.
Final items used:
18 AWG Stranded Copper Wire. (27" in Length) (14 was too hard to manage)
Solder Materials and Tools
Heat Shrink
Male and Female connectors
Hot Glue
Drill and Drill Bit
Final ST-814 Mod:
Dissembled entire ST-814 (4 Philips screws for back cover, and 2 Philips screws for main control unit)
Cut off the very end of the ST-814 antenna sheath (The last 1/4 upward bend)
Prepped antenna end and new extension wire for solder. (Cleaned and Fluxed)
Soldered new extension wire to ST-814 antenna end.
Shrink wraps new extension wire to antenna.
Drilled hole in upper rear cover.
Ran wire through and laid out internal path so rear cover could be re-installed.
8.) Placed a small amount of hot glue to the area where the wire penetrates through the rear cover.
Re-installed Rear Cover.
Made up terminal ends to allow for removal from inside Freezer.
Stretched extension wire jacket beyond wire strands and forced hot glue into area.
Re-assemble remaining covers.
Freezer Mod:
Found easiest area in Freezer to facilitate installation. (For Mine, Upper Corner of Inner Door Liner)
Loosened all liner / gasket screws for that corner.
Pulled liner away from outer door skin and pulled gasket up.
Drilled small hole (using same drill bit for ST-814 outer housing) though liner.
Passed extension wire under the gasket, through the liner and up.
Positioned ST-814 and wire for best placement.
Re-installed gasket section making sure extension wire was between back of gasket and door skin and tighten down all corner screws.
8.) Placed a very small amount of hot glue around the interior hole that was drilled.
Ran extension wire along top of door gasket and place one small drop of hot glue in the middle area to help retention.
Some Pictures: (Can’t figure out how to get thumbnails to work)
Would it not have been an option to put just the temperature sensor in the freezer? I could not see from the picture where the sensor is located on the circuit board but then you could have the main unit out side of the freezer and the battery would last longer. (Just an idea).
I know this is an old post, but ServiceXp, you still seem active on this forum, so I’m hoping you see this. I’m very interested in using this to connect to my Simon XT to monitor a fridge. Your instructions are great, however it’s not clear from your pictures where you soldered the external antenna. I’d appreciate it if you could clarify.
Thanks!
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