Case for WiTcontroller

I recently got into the world of DCC control for my train set, and have built and am using the excellent [DIY DCC-EX system][1]. I initially used the [WiThrottle iPhone app][2] to control my trains, but found the [WiTcontroller physical controller][3] to be easier to use since it has a physical knob and switches. The WiTcontroller is a simple DIY handheld controller that talks to a WiThrottle Server (JMRI, DCC-EX, etc) using the WiThrottle protocol to control DCC model trains.

This case is for a WiTcontroller using a 2.42" OLED display plus five dedicated pushbutton switches, in addition to the standard processor, keypad, rotary encoder, and battery. Full instructions for the WiTcontroller hardware and software are available at [this link][4].

Here are the parts that I used (Amazon links may earn me a small commission):

[LOLIN32 ESP32 Lite][5]
[2.42" OLED Display][6]
[3x4 Keyboard][7]
[Rotary Encoder Module][8]
[Pushbutton Switches][9]
[Rocker (power) Switch][10]
[3.7V LiPo Battery][11] (note: the connector polarity is reversed - see below)

Several small screws from my parts bin were used to assemble the controller, but if you need a source, [here is a nice assortment of small screws][12]. I use six 3mm screws and [heat set inserts like these][13] to hold the case together. You will also need jumper wires - I find separated [ribbon cable][14] works well.

I have included a version of the front cover in the STL files that should accept small screws like the ones in the set linked above instead of the heat set inserts if you'd prefer to make yours that way (Front_Cover_NO_INSERTS.stl). Note that I also included a Threaded Insert Practice Piece (Threaded_Insert_Practice_Piece.stl) so you can experiment with the heat set inserts before you try to put them into the front cover for real.

At the request of user gwaland, I have included a version of the front cover in the STL files that better fit the heat set inserts he used (Front Cover WITH 4mm THREADED INSERT HOLES.stl). Here is a [link to the inserts][15] which he recommended (note: I have not tested these myself).

All of the parts can be printed at 0.2mm layer height with 20 or 30% infill. The Back Cover and Knob will need support material. Everything else doesn't need support.

Before installing the electronic components the Display Cover will need to be glued to the Front Cover with cyanoacrylate glue (aka CA or crazy glue) or similar adhesive. You may find it easier to align, hold, and glue the parts together with the Back Cover in place - just be sure to not get glue on the Back Cover and get it stuck to the front.

The battery connector on the LOLIN32 ESP32 Lite has a non-standard polarity (it's reversed for any LiPo battery with a JST connector that I can find). Be sure to pay close attention to the "+" and "-" markings on the ESP board and make sure the pins on the battery connector are correct BEFORE you plug it in. I modified my battery to make it the correct polarity for the ESP - the pin contacts on the JST connector can be removed if you push down the locking tab of the contact with something sharp like a pin or needle while pulling it out of the JST housing. Be careful not to let the bare contacts touch each other when you remove them! Reassemble the pins back into the housing with the correct polarity and you should be good to go. Note also that my design includes a power switch on the battery leads so the battery leads will need to be cut and extended with some wire and heat shrink tubing or similar to prevent short circuits (see the schematic included in the photos above).

The battery I used is a 3.7V 603450 type. The mounting space in the case bottom will fit any battery measuring up to 52x34x6.4mm as designed.

I included the battery monitor resistors as described in the WiTcontroller github link above. My resistors are soldered directly on the ESP board as you can see on the "Inside" photo.

Note that I am not responsible for the WiTcontroller code.

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