Pre-Compiled miniThrottle

miniThrottle: A model railroad WiFi throttle.

↓↓ Dig deeper ↓↓

What is it?

It is a pre-configured and pre-compiled version of miniThrottle. Calling it prebuilt is a bit of a misnomer as it is not a ready-to-run option. It is a pre compiled image. You still need to source your own hardware and assemble it yourself. But the firmware is ready to install, and assembly follows a recipe. As such it can be installed on a specific hardware configuation, which then allows:

Note: The pre-compiled version is not suitable for a stand-alone / hand-held WiFi throttle.

While it is possible to connect the module directly to DCC-Ex, this is not recommended. Mounting the module on an Arduino prototyping board, requires slightly more effort and allows the module to be stacked on DCC-Ex.

Install a Pre-Compiled miniThrottle System

As a precompiled version, no compiler / Arduino-IDE is required. Some downloads are required as indicated below. And the Esp32 module is connected via a USB cable in order to flash the precompiled image to it.

By downloading from this site you accept the conditions of use.

  1. Start by downloading the ESP flash download tools. If you don't already have these and unzip the file to your pc. Note these tools are only available for Windows systems.
  2. Download the pre compiled image and unzip to a working directory. This should contain files with memory location in their names which we will use at a later stage.
    File NameSave AtFunction
    miniThrottle_bin/0x1000_bootloader.bin0x1000Boot loader
    miniThrottle_bin/0x8000_partitions.bin0x8000Partition table
    miniThrottle_bin/0xe000_ota_data.bin0xe000Over The Air (OTA) update data
    miniThrottle_bin/0x10000_miniThrottle.bin0x10000Program code
  3. Connect the Esp32 module to your PC using a USB cable.
  4. Go to the folder containing the ESP flash download tools, and run the application. This opens both a control and a status window. The control windows are discussed below.
  5. initial control menu from ESP Tools In the window select processor type of ESP32, and develop mode. Factory mode would allow you to perform the install on to multiple units simultaneosly.
  6. Define files to upload in ESP Tools Now using the elipisis button next to the file names select the files you want to write to the Esp32 module. Note if the option is unchecked in the left column then that image file won't be written to the module. Copy the file location to the @ location. Other settings to look for are
    Once set you should be able to select start to flash the image to the module. The status window should show details and give an indication of progress. Once compete a blue Finished indicator will appear in the control window, and you can close the ESP tools window(s).

    After the image is burnt to the module, you should boot it before typing to access it. You will be able to access it using either the serial port (say using putty or TeraTerm terminal emulation) or using a web browser. Initially it on't have details of your local network, but the module will initially presnt a "dccStation" network which you can join. On this dccStation network connect to and if prompted for a password, your initial user is "admin" with a password of "secret". (without the quotes in either user name or password.)

Physical Connections

Wiring diagram for the pre-compiled miniThrottle

The module used can found by searching Google (or other search engines) using the term "esp32 oled", and purchased from AliExpress, Ebay, Amazon etc.

Left Hand Side
36 / SVP10k - 20k potentiometer centre / slider, pot pin 2 (any linear potentioneter in this range should be OK.)
25, 264 x 4 keypad, membrane type recommended, same keypad as pins 0, 2, 14, 12, 13 and 15.
S1, CM, SO, CLno connection - used to access internal memory
3Vpotentiometer high / fast side / pot pin 3
GNDpotentiometer low / slow side / pot pin 1
Right Hand Side
SVN, 39RX connect to DCC-Ex TX pin (via 5K resistor to DCC-Ex and 10K resistor to GND)
16TX connect to DCC-Ex RX pin
5, 4no connection - used by I2C connection of display
0, 2, 14, 12, 13, 154 x 4 keypad, membrane type recommended, same keypad as pins 25 and 26.
RX, TXno connection - same console connection as USB serial
GNDConnect DCC-Ex GND, common ground
5V5v supply from DCC-Ex

Note: If using this as WiFi relay only (ie no local controls) then the potentiometer and keypad connections are left disconnected. In this case you don't need a module with a display, as long as pins SVN (39) and 16 are available to connect to the DCC-Ex module.

First Time Use

Time to customise the unit!

There are numerous customisations that can be set through the web interface as shown in the WiFi Options

You can configure the unit either via web page or connecting to the serial port. The serial port parameters are 115200 (speed), 8bits, no parity, 1 stop bit and no flow control. On a PC you need a terminal emulation such as Putty or TeraTerm-Pro and a USB cable attached to the miniThrottle device. It is assumed that for most users the web page will be the best option. However, the serial port option can still be useful if you have forgotten the admin password.

On the first start the unit should run an unsecured access point called "dccStation". No password is required. Connect to this access point and use your web browser to go to To access anything other than the status page you will need an admin password. This is initally a user of "admin" and a password of "mysecret", neither of which contain either quotes or capital letters. Now work through the various options to customise your miniThrottle device. See the web interface configuration page to review details, but here are some general comments.

Thank you for visiting this websiteHome