RMIS 12S SDK v1 – Specification


RMIS (Remote Monitoring IoT System)

Ideal for remote monitoring DC Voltage and Current of:

  • Green Energy Systems
  • Renewable Energy Systems
  • Batteries
  • Solar Panels
  • Wind Generators
  • Hydro Power Generators
  • Rain Gutter Power Generators
  • Thermoelectric Power Generator
  • Water Tower Power Generators
  • Turbines

This exciting new RMIS-1 – STEM SDK kit was originally designed for the GB3FW repeater site and displayed interest as a STEM project – so here it is!



RMIS v1 specification overview:

  • The board is available in TWO standard voltage ranges (although you can alter this range if required with a single resistor change per channel).  The  variants  and features are  shown  below:
  • Each will monitor 4 x channels
    • Each +/- 30A current and voltage up to 30V, or 60V
      • 8 x channels in total.
      • Allow monitoring of charge and discharging of current sources.
      • Voltage monitoring, on each channel, can be isolated from current, if needed.
      • Ideal maximum continuous current 15A, per channel.
    • Each of these channels are isolated.
    • Common ground for voltage monitoring.
    • The current measured is also positive and negative, so RMIS can monitor both charging and discharging DC currents in each channel.  This makes it ideal for battery monitoring, solar and wind charging etc.
  • In addition, the board has a digital temperature sensor included.
    • Provides feedback on the PCB and ambient temperature.
  • On board 5V and 3V3 regulators.
    • Maximum of 15V DC input to the PCB  power.
    • DC Input Voltage monitored by separate input to ESP8266 ADC.
  • Compact Board
  • Easy to install and setup


An example of the output can be seen here  as highlighted below.   Our sample code posts live readings to ThingSpeak website.


Power Connectors

The DC Power Connectors on the RMIS-1 – STEM SDK are quality 5mm spacing, 32A Insulated Screw Terminal Blocks – with a cable diameter range of 0.5 mm² to 4 mm². This equates to a conductor cross section of 20 to 10 AWG.

These are not pre-soldered to the SDK PCB, so enabling the option to solder the cables directly, or use the terminal blocks.


Data Connections

The RMIS has two headers.

  • UART with RTS and DTR (avoids the need to press reset when flashing)
  • I2C (expansion)


Software Code

Can be easily flashed with any ESP8266 firmware code in order to connect to MQTT or other systems.

Arduino IDE based software / firmware code for this RMIS ESP project will be provided in our Wiki, to easily get you up and running.  This code connects the RMIS-1 – STEM SDK to your Wi-Fi and then uploads to a ThingSpeak channel.  FREE ThingSpeak accounts for small non-commercial projects are available (providing up to four channels), so you could have more than one project running at once.

Example Outputs using ThingSpeak


Note regarding the UART cable.

RMIS-1 – STEM SDK has been designed to flash/program easily by using the RTS and DTR connections on a UART. This enables automatically flashing without pressing/holding any buttons).  Details are in the Wiki.


In the Box

RMIS-1 – STEM SDK is supplied as a Developer Kit PCB.  SMD Populated and Tested.

You will need to update the firmware with your preferred open source firmware, using a standard UART (3v3).  Working examples of code for ThingSpeak can be found in our Wiki

The RMIS-1 – STEM SDK Developer Kit contains:

  • 1 x  RMIS-1– STEM SDK SMD PCB (tested).  Ready to Program
  • 1 x Set of header pins (for UART, SPI or I2C)
  • 5 pairs x PCB Screw Terminals (unsoldered)


Other Details

Further information may be found in our downloads and Wiki pages



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