D1 Mini DIN Rail Case 1TE, RS485

Simple DIN Rail case to hold a Wemos D1 Mini (clone) and a cheap MAX485 PCB.

This thing is a DIN Rail case (Hutschienengehäuse, DIN43880 - see also https://de.wikipedia.org/wiki/DIN_43880 ) that I built in order to send the values of an Eastron SDM120 energy meter on my DIN rail (German: Hutschiene or Tragschiene) to an MQTT broker. This is done using a cheap ESP8266 based Wemos D1 mini (in my case a clone, as the genuine ones after rev 2.2 changed the position of the Micro USB port) and an even cheaper MAX485 PCB. The case provides space for 5V Power (+ and -) and RS485 screw terminal blocks. You will also have access to the reset button (from the top) and to Micro USB (if the DIN rail cover inside an installation is removed) for updating your software.

You have to print:

• case
• cover
• clip (to fixate the case on the DIN rail
• holder (to keep the spring for the clip in place)

Hardware needed:

• Wemos D1 Mini clone
• MAX485 module (TTL to RS485)
• 2 5mm 2P or 3P screw terminal blocks (0 or 90 deg - see also TODO below) - cut off the nose for 3P versions to fit in
• wires - optionally with DuPont connectors
• spring - mine seems to be 5.5mm diameter and 15.5mm long
• external DIN rail 5V power supply (e.g. Meanwell HDR-15-5)

Software:

• e.g. https://github.com/codmpm/esp-sdm-mqtt - or my modification (to follow ...)

Connections:

• 5V + Screw terminal <-->MAX485 VCC <--> D1 Mini 5V
• 5V - Screw terminal <--> MAX485 GND <--> D1 Mini G
• D1 Mini Pin D1 <--> MAX485 RO
• D1 Mini Pin D2 <--> MAX485 DI
• D1 Mini Pin D4 <--> MAX485 RE and DE (bridge the two pins)
• RS485 A Screw terminal <--> MAX485 A
• RS485 B Screw terminal <--> MAX485 B

NOTES:

• the screw terminal blocks I had were two different models (one with 0 and one with 90 deg), thus top and bottom holders for them are slightly different. If I rebuild this thing than I will try to use the same ones everywhere.
• those cheap cables soldered on the D1 mini tend to break - I might want to use a connector later, but space in a 1TE case is limited ...
• redesign for a current rev 3.1.0 Wemos D1 mini
• break off a piece of the D1 clips if the DuPoint connectors are too long
• break off the thin layer behind the clip if it hangs

Changes:

• it has been requested in the comments to add the source file for easier editing. I unfortunately do not have final Sketchup files for the models available, as they needed some final fixing. The files in the attachment should therefore be considered building blocks for remixing. Some tools like Sketchup can also import STL files - I recommend this over the newly attached Sketchup files.