Industrial Automation
Home Automation
Microcontroller Boards

IoThing Digital

Open source digital I/O module with two SPDT relays and two isolated AC or DC input channels for RaspberryPi, Arduino, and other embedded platforms

$1,797 raised

of $2,500 goal

72% Funded Time Expired

Recent Updates

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IoThing Digital is an open source digital I/O module with two high-power Omron G5Q-14 relays and two isolated digital-input channels (based on Texas Instruments ISO1211). Designed for ease of use with Raspberry Pi, Arduino, and other embedded platforms, it accepts digital input of both DC and AC signals to support a broad range of input-voltage levels. You can choose the voltage range, be it 60 VDC, 220 VAC, or anything else up to 300 V. IoThing Digital also includes a DC-DC converter, EEPROM for storing configuration data, and a slot for mikroBUS connectivity and to attach microcontroller modules.

Between our five adapter shields, you can use IoThing Digital as an add-on module for many popular third-party microcontroller boards, including Arduino Nano, STM Nucleo-32, Adafruit Feather, SparkFun Thing Plus, Particle, Teensy, Raspberry Pi PICO, and MikroElektronika MINI. You can find documentation for these adapters on our website and in our GitHub repository.

We also offer an RPi-to-mikroBUS adapter that allows you to connect your Raspberry Pi single-board computer (SBC) to the mikroBUS connector on IoThing Digital or to other I²C modules. And, if you’re working with a Raspberry Pi 3A+, you will be glad to hear that IoThing Digital adheres to the same 65 x 56 mm form factor.

Custom System-on-Module (SoM) Boards Also Available

During this campaign, we are also making three custom SoMs available in limited quantities: one with an LPC824 microcontroller, one with a a SAMD21 microcontroller, and one with an STM32F411 microcontroller. Technical documentation for all three can be found in our GitHub repository.

The LPC824 Lite Microcontroller Board

The SAMD21 Lite Microcontroller Board

The STM32F411 Lite Microcontroller Board

Perfect for Professionals & Hobbyists

IoThing Digital is perfect for engineers working on distributed or decentralized control systems, IoT and IIoT product designers, and amateur developers – anyone who needs a reliable module upon which to build compact, embedded control systems. IoThing Digital can be used to automate everything from thermometers to windows to heating systems to full-scale smart homes, smart gardens, and smart farms.


IoThing Digital (2 Relays & 2 Digital Inputs)2 Relays & 6 GPIO4 Relays & 8 Digital Inputs2 Relays & 8 Digital Inputs4 Relays & 4 Digital Inputs
Manufacturer Alt-Step NCD ERE Company, Ltd Widgetlords Electronics Sequent Microsystems
Components A single IoThing Digital module General-purpose, 2-channel SPDT relay shield & 6 GPIO w/ IoT interface I2C Relay 24V 10A PCF8574 & I2C OPTO 15-30V PCF8574 Pi-SPi-8KO relay output & Pi-SPi-8DI RPi digital input Four relays & four inputs for RPi
Power Supply 9 - 48 VDC 5 VDC 5 VDC 5 VDC 5 VDC
Digital Input RangeUp to 300 VDC & VAC 0-5 VDC Up to 30 VDC Up to 24 VDC Up to 48 VDC & VAC
Digital Input IsolationIndividual None Individual Group Group
InterfaceI²C I²C I²C SPI I²C
Microcontroller IntegrationsRaspberry, Arduino, Adafruit, Teensy, SparkFan, Particle, MikroElektronika, BOKRA Raspberry, Arduino, Adafruit, Particle, Onion, USB devices Wiring required Raspberry Pi Raspberry Pi
Dimensions65x56 mm 93x72 mm 87x52 mm + 42.5x72 mm 85x56 mm + 85x56 mm 93 x 56 mm
Channels/cm²1.10 1.19 2.11 1.05 1.54
Price$40 $43 $87 $50 $35

Efficient, Compliant, Independent ISO1211 Inputs

For its inputs, IoThing Digital uses the Texas Instruments (TI) ISO1211 instead of a traditional optocoupler-based solution. The primary benefits of this solution include:

  1. Reduced power dissipation, which leads to a significant reduction in the heating of the board

A traditional board (heating to 84.1°) compared to an ISO1211-based board (heating to 44.9°)

  1. Guaranteed compliance with IEC 61131-2

  2. Channel independence, which prevents damage to one channel on the field side (due to a short circuit, for example) from impacting any of the other channels

Features & Specifications

IoThing Digital Pinout

Support & Documentation

You can find technical details and board schematics in our product datasheet, documentation for our adapter shields on our website, and much more in our GitHub repository. You can also reach out using the Ask a technical question link below.

Manufacturing Plan

IoThing Digital has already been tested and deployed in several projects. We produced a trial batch of modules for this purpose and used them to approve the design of the board. Our PCBs will be manufactured in China and tested there before being shipped to the US for fulfillment. We have longstanding and successful working relationships with several contract manufacturers, including the one with whom we currently expect to partner on IoThing Digital production.

We are working closely with a number of distributors and vendors to accelerate component acquisition so we can manufacture IoThing Digital as quickly as possible despite current component-availability challenges.

Fulfillment & Logistics

After testing and packaging the production batch of IoThing Digital boards, we will send them on to Crowd Supply’s fulfillment partner, Mouser Electronics, who will distribute them to backers worldwide. You can learn more about Crowd Supply’s fulfillment service under Ordering, Paying, and Shipping in their guide.

Risks & Challenges

The first batch of IoThing Digital has already been manufactured and tested, so we have no concerns about issues with the module itself. In that respect, risk to backers is low. However, the global chip shortage—caused in part by the COVID-19 pandemic—is such that we are constantly on the lookout for possible component-availability challenges. Should we encounter any such issues, we will inform you by way of a campaign update.

While we currently anticipate no production issues, a surge in COVID-19 incidence could cause delays in the fabrication or assembly of IoThing Digital PCBs. In the event of significant delays, however, we are prepared to change manufacturers in order to mitigate the issue. And of course, if we are somehow unable to complete IoThing Digital fulfillment, we will offer backers a full refund.

In the Press

Geeky Gadgets

"Developers, engineers and makers searching for a professional grade digital input output module and relay board may be interested in the IoThing Digital board..."

Hackster News

"Board offers isolated AC/DC channels to 300V, two Omron relays, and both mikroBUS and Grove connectors for expansion."

"IoThing Digital is a professional digital I/O module with two high-power Omron G5Q-14 relays and two digital input channels... It allows digital input of both DC and AC signals, so you are not limited in your choice of input voltage level."

Ask a Question

Produced by AlterStep in Haifa, Israel.

Sold and shipped by Crowd Supply.

IoThing Digital

IoThing Digital is a relay-output and digital-input module manufactured in the Raspberry Pi A+ form factor (65 x 56 mm). It contains two SPDT relays, G5Q-14, and two channels of digital input (both VDC and VAC) based on ISO1211 chips.

$40 $8 US Shipping / $18 Worldwide

IoThing Digital Adapter Shield for SBCs & MCU Boards

Five different Adapter shields that allow you to connect IoThing Digital to an Arduino Nano, STM Nucleo-32, Adafruit Feather, SparkFun Thing Plus, Particle, Teensy, Raspberry Pi PICO, or Mikroelektronika MINI.

$9 $8 US Shipping / $18 Worldwide

STM32F411 Lite Microcontroller Board

An STM32F411-powered microcontroller board compatible with the mikroBUS "S" standard and ready to slot into IoThing Digital. Operates at 100 MHz and includes 512 kB of flash memory and 128 kB of RAM.

$22 $8 US Shipping / $18 Worldwide

About the Team


Software and Hardware for IoT and Cloud Applications.

Vladimir K

See Also

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