Servo/software/available now!

Follow the github link from the downloads page for the binary file to download, and right above it the pdf file to show you what to do with it…


Settng/up/mqTrains LCD?

When you power up an mqTrains module, on first power up, it will create an access point (AP) mqTrains-0001 and you can use your computer, phone or tablet to connect to it…you then proceed to with your browser to get to the web page to configure it, and when you are successful in configuring your SSID, WepKey, MQTT’s IP Address and the base topic to subscribe too, it will reboot, connect to your WiFi router, connect to the MQTT broker (server) and publish the IP address of the module to with "/baseTopic/IPA is here!", and now you know where to find the web page again to configure the servos and I/O as you need. The AP will turn off once the module publish the IPA message. Next power cycle AP on again and off when IPA is published. So you have a way to reconnect to it on power up. But, if you don’t have a way to see the MQTT messages easily, we just added and tested a very inexpensive SSD1306 OLED LCD module (also explained in a Random Nerd Tutorial here). So consider having one or two LCDs handy to monitor your first mqTrains device:


mqTrains/getting/ready HowWhatWhen

Okay, we are getting closer to the release, so you might want to start getting some parts and install some software! We might just release the binary files first, in which case you would need to read up on PlatformIO, or if we just want you to get lost in all the details, we will upload all the code into github or gitlab to use with the Arduino IDE.

So, starting with the latter, the Arduino IDE (we recommend at least version 1.8.12) is needed with the tool set to compile and upload the code (ESP8266 Community version 2.7.4 recommended), as well as the little tool to upload the file system (at least version 2.6.0) with the web pages and .json configuration files (how to here).

And then you are going to need all the libraries installed required to make this work. You should be able to download and install most of them within the Arduino IDE, just make sure that the ESPAsyncWebServer is also installed, even though it might come from another package when you do the search in Manage Libraries… (Ctrl+Shift+I). If not, just as easy to download and unzip the code from here:

Here is the list with the versions required:

  • Wire at version 1.0
  • LittleFS at version 0.1.0
  • JSON
    • ArduinoJSON by Bernoit Blanchon 6.17.2 (was 6.15.2)
  • Queue
    • ArduinoQueue by Einar Arnason, version 1.2.3
  • i2c IO
    • Adafruit_MCP23017_Arduino_Library at version 1.1.0
  • i2c pwm servos:
    • Adafruit PWM Servo Driver Library at version 2.4.0
  • MQTT
    • PubSubClient by Nick O’Leary Version 2.8.0
  • WebServer:
    • ESPAsyncWebServer at version 1.2.3
    • ESPAsyncTCP at version 1.2.2
      • cd libraries && git clone *
  • mDNS:
    • esp8266_mdns at version 1.1.7
  • Hash at version 1.0

Ok, now that you have all the software tools under control, here is the minimum Hardware needed:

  • Computer to run all the software above on, and that includes operating systems like Windows, Linux and Mac, even Raspbian.
  • A USB connector for a USB cable to go to the ESP8266 programmer
  • An ESP8266 programmer board that makes USB into RX/TX, provides 3v3 to the ESP and has a switch or button to pull the GPIO low on ESP power up, to put it in boot mode.
  • And ESP8266, and this can be any NodeMCU variant, but in order to make this as inexpensive as possible, and limit the growth in software, an ESP-01 is sufficient to connect to the i2c modules or the 1-wire LEDs for the first round
  • A PCA9685 PWM driver module, with a 5V power supply capable of enough Amps to control all you 16 servos from anywhere to anywhere else, even at startup, when they all will consume power!
  • Or a MCP23017 module with the 16 I/O pins to read sensors or control ouputs (3.3V at this point)
  • Or a whole bunch of WS2811 or WS2812b devices to control LEDs on one looooong wire.
  • We are in the process of making the interface hardware between the Modules and ESP01, but if you can solder 4 wires (3v3, GND, SCL and SDA) on top of the ESP01 (or to the NodeMCU) you are ready.

Debugging/your/MQTT help!

Starting mosquitto from the command line, you can use the ‘-v’ (or ‘–verbose’) option for showing verbose messages…this will override the logtype option in the config file. So first step, when something is not going right, start the MQTT server manually with mosquitto -v and watch what the server does while you debug the problem.

If you don’t have direct access to the Broker/Server, you can also check out MQTTBox, works on most platforms…great tip from David B., thank you.

Create a new MQTT Client, with some unique MQTT Client Name (MeBox will work), select the protocol you are using in your application, and enter the hostname or IP address for the Host. Enter Username and Password, if used, and check or uncheck all the other boxes that are application to your setup. Then click Save and selecting the “MeBox” client in the list, will allow you to add Publishers to Publish to a Topic, or Subscribers to Subscribe to one or more Topics, with the wildcards (Single Level ‘+’ and Multilevel ‘#’) , as usual.

Very easy to monitor and interact with the MQTT Server: a Published message has a “Publish again” arrow, avoiding quite a but of typing.; restarting MQTTBox will automatically connect (if the option was selected), but you will need to click the Subscribe button in each Subscriber window.


Uploading/code/to/ESP8266/with mqTrains_xxx.bin

Monitoring the verbose output in the debug window in the Arduino 1.8.12 IDE, we see:

C:\Users\name\AppData\Local\Arduino15\packages\esp8266\tools\python3\3.7.2-post1/python3 C:\Users\name\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\2.7.0/tools/ --chip esp8266 --port COM4 --baud 115200 --before default_reset --after hard_reset write_flash 0x0 mqTrainsIO_xxx.bin v2.8
Serial port COM4

Enable verbose output with Settings (Ctrl+Comma). File -> Preferences -> Show verbose output during: [ x ] compilation [ x ] upload

So, if we do this in Linux or on a Mac or Raspberry Pi:
All we need is
sudo apt-get update
sudo apt-get install python python-pip
sudo pip install esptool

And then --chip esp8266 --port /dev/ ttyUSB0 --baud 460800 --before default_reset --after hard_reset write_flash 0x0 mqTrains_ServoPCA_1.0_1MB.bin

For the Windows kind, there is a Nodemcu-Flasher tool here in a 32 and 64 bit version which you can specify the bin file on the Config tab:

Set the appropriate Flash Size, Flash speed and SPI Mode on the Advanced tab:

And then head back to the Operation tab and a click “Flash(F)”:

Of course, the Windows device driver needs to be in place for the USB programmer you are using (COM7 shown here).

We also recommend using this little DYI Mall programmer which avoids the slide switch at power up to be in program mode, but instead gives you a reset button and the same 8 pins on the ESP-01 to connect to the next i2c board:


Setting/up/MQTT/Broker mosquitto


mosquitto-1.6.12a-install-windows-x64.exe (example)

Select Files and Service

To start the service, Computer Management (right-click on My Computer, Manage) -> Services and Applications->Services->Mosquitto Broker->right click->Start

(You can also set the service to Automatic in right click on the service->Properties->Startup type)

If not run as a service, you can start it with
C:\”Program Files”\mosquitto\mosquitto.exe -v -c “C:\Program Files\mosquitto\mosquitto.conf”

To test, run:
C:\Program Files\mosquitto\mosquitto_sub -h localhost -v -t “TxNamib/#”

If the service is not running or accessible, the error wil show:
Error: No connection could be made because the target machine actively refused it.

Else, you will only see a message if it was “retained”, or you publish something to TxNamib now
C:\”Program Files”\mosquitto\mosquitto_pub -h localhost -t “TxNamib/servo.2003/03” -r -m “CLOSED”
C:\”Program Files”\mosquitto\mosquitto_pub -h localhost -t “TxNamib/servo.2003/03” -r -m “THROWN”

Ubuntu and Raspberry Pi (3, 4, 400 and Zero W):
sudo apt-get install mosquitto


snap install mosquitto

Older versions of Ubuntu:
sudo apt-add-repository ppa:mosquitto-dev/mosquitto-ppa
sudo apt-get update


We/are/live TRUE

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