[Accepted] STETEL-Open Source ESP32-C3 Dev-Board “Powered by IoTeX”

Proposal details

Project Name

Open Source ESP32-C3 Dev-Board “Powered by IoTeX”

Project Type

MachineFi / IoT Device

Proposal Description

We want to build and deliver an open-source hardware design for an IoT board containing several sensors and radio-bearers, besides an IoTeX-compatible secure element, that can be used by anyone as an example or the foundation for future “Powered by IoTeX” IoT devices.

The presence of a specialized plug & trust secure element chip allows easy and seamless integration with the IoTeX ecosystem, especially with the upcoming Layer 2 network (TruStream) that supports cryptographic verification of devices identities and data integrity.

The following devices will be integrated on-board:

  • GPS (integrated into Simcom SIM7080G)

  • Temperature, Pressure and Humidity (Bosch BME280)

  • Accelerometer (Stm LIS2DE12TR)

  • Ambient Light (Rohm BH1730FVC)

  • User Button

  • Rgb Led

  • Buzzer

The board supports the following bearers:

  • Wifi 2.4GHz (ESP32-C3 module)

  • Bluetooth LE (ESP32-C3 module)

  • NB-IoT & LTE-M (Simcom SIM7080G with nano-sim holder)

Other features:

  • RISC-V Cpu will soon support the Arduino IDE

  • 4MB of onboard flash to contain the firmware

  • Secure Element connected via SPI with several cryptographic algorithms (NXP SE050A2HQ1)

  • Power Management IC with power on/off, battery charging, reset functionalities

  • Can be flashed/updated via the USB port

Value proposition

IoTeX aims to create a secure and reliable platform for next-gen IoT devices, based on blockchain technology, secure hardware, and layer 2 networks. However, while experimenting with software layers is generally simpler in terms of the resources required, building hardware that fully supports the IoTeX platform may seem complex and expensive to someone.

With this project, we want to demonstrate how it is possible to design a simple, inexpensive, IoT device based on popular components, flexible, but at the same time secure and ready to be integrated with IoTeX using the simplicity of the IoTeX “MachineFi” vision. This way, we will make available an alternative and cheaper project to the excellent Pebble Tracker device by IoTeX, including firmware examples to communicate with the IoTeX “TruStream” Layer 2 network, as well as for direct interaction with the Layer 1 blockchain. This will make a complete “Quickstart” package for anyone interested in “hardware side” IoTeX development.


Open Source (license Apache2/MIT)

  • KiCad Schematics.

  • One firmware that acts as a validation and testing tool.

  • One or more firmware examples to interact with the IoTeX Layer 2 TruStream network (over MQTT)

  • One or more firmware examples to interact with the IoTeX Layer 1 Blockchain (Using IoTeX Arduino SDK)

Other Deliverables

  • 4 layers Pcb layout.

  • Up to Nr. 5 first prototype boards (will be used to validate the schematics and Pcb).

  • Second round of schematics and PCBs with workarounds and fixes (if required).


NOTE: following durations (excluded the first milestone) may be impacted/delayed by the current global electronics components shortage.

  • Milestone 1:

    • Duration (weeks): 3 weeks

    • Deliverables: schematics and Pcb layouts

    • Funds request: 6000 EUR (6,950 USD)

  • Milestone 2:

    • Duration (weeks): 3 weeks

    • Deliverables: first assembled Pcb boards

    • Funds request: 6000 EUR labor + 1000 EUR material (8,100 USD)

  • Milestone 3:

    • Duration (weeks): 3 weeks

    • Deliverables: hardware validation and bug fixing, Testing firmware passes all green

    • Funds request: 3000 EUR (3,470 USD)

Total funds requested

We ask 50% of the project to be funded by the IoTeX foundation:

8,000 EUR (9,260 USD)

About your Team

We are Stetel Things. We are a spin-off of Stetel, bringing all our 29 years of experience in software and hardware development to give the most advanced IoT solutions to the market! We keep up with innovation and sometimes we create it!

From complex circuits making to 3D printing, we design, create and assemble unique pieces of handcraft to serve your needs.

We have already some IoT products successfully launched on the market: Urban Tracker a small, discrete device to locate object in outdoor and indoor environments; a Logistic Tracking solution of for business; MAIA, and IoT development board for makers.




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=== Please add Milestone Reports below ===

Milestone Report: #1
:pencil:Invoice form has been filled out correctly for this milestone.
Deliverable Name : (e.g.: “Schematics and Pcb layouts” )
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Payment tx : Transaction hash


This is an exciting proposal and we should support the hardware builders! I have two personal thoughts:

  • can this board support different Arduino sensors/parts? if so, great!
  • can this board support different radio frontends? for example, if someone wants to make it work with lora network, he can just plug in play a lora module?

Nice proposal! Thanks for this submission :slight_smile:

  • The ESP32-C3 module has limited GPIO pins which are used for the onboard peripherals. We aim however to expose at least the I2C bus which can be used with a broad variety of sensors and actuators. These are often used by the Arduino community. We are also investigating if the GPIO pins of the mobile module can be used.

  • Radio Front-end: The first milestone will deliver a schematic that is using the NB-IoT/LTE-M radio module. This schematic is however open source and can therefore be used by everyone as a starting point to replace the radio module with a Lora one. The first proto-boards will also have the NB-IoT/LTE-M module (Milestone 2) but we’re not excluding to build, in a near future and a separated project context, also a Lora version.


We are glad to inform you that the IoTeX Foundation decided to grant the funds for your proposal.
When you think the deliverables for a milestone are ready, please edit your original post and append a milestone report according to Grant Issuance Rules and contact me for review at:

Congratulations @stetel :partying_face:!


We are so happy for this approval ! Thanks :bowing_man:

As soon as we hit milestone no. 1 we will append the report to the post.

Given the approval from yesterday the first milestone is foreseen for the 7th of December.
The deliverables will be published on github.

Because of the electronic components shortage we are already working on the shopping list. :wink:


agree completely. :ok_hand:

Milestone 1 achieved

Happy to announce that we’ve just reached our first Milestone! :partying_face:

The IoTeX Devboard has been designed and can be found here: IoTeX Devboard on Github

Going to prepare the first Milestone report. Working hard to reach Milestone 2.


Thank you @stetel for this update! The repository looks good, looking forward to the results of the prototyping!

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That was quick!
Looks great, looking forward to testing it

1 Like

First assembly about to start

We have now all the needed “ingredients” for our Board recipe.

Checkout the: IoTeX Devboard on Github and take a look on the bare PCBs which we are about to assembly with the components in the next few days so that we achieve Milestone 2 .


Update for Milestone 2: IoTeX Devboard #0 is alive :partying_face:

See the IoTeX Devboard on GitHub for a real picture of board #0 which replaces the rendering picture.

  • The smoke tests have been passed. :white_check_mark: No fire :fire: !
  • All voltages look good so far. :white_check_mark:
  • We are preparing the first testing firmware which will be published on Github as well.

There is a little “but” though:
You can notice that a little chip is missing: it’s the voltage translator that allows to communicate with the mobile module. Unfortunately we received the wrong version of that chip, and are now waiting to get the right one (hoping the global chip shortage doesn’t add its delays).
For the sake of our commitment, we will declare Milestone 2 reached only after this chip is also on the board, enabling the mobile connectivity.
In the meantime the board should be able to operate with all other sensors, radios and peripherals.

Stay tuned !


Exciting to see the progress here. What is the plan to hook this up with trustream @stetel?

Trustream is for sure the best protocol candidate for several of the possible applications that can be implemented on the board.
We are not yet there but the usage of Trustream for one of our PoC apps is on our Radar.

Milestone 2 is finally completed: Took a while but the missing component is now available and assembled on the boards :wink:

  • With the level shifter in place we found a little defect in the design: the “status” line of the Simcom mobile module can not be read correctly by the ESP32-C3 module. This means that we will release soon a revision of the schematics and a corrected PCB. The missing status line doesn’t impact though the possibility to use the whole board.
  • We are proceeding to Milestone 3 with the implementation of the “T=1” protocol for the secure element communication (NXP SE050 chip).
  • All other peripherals are working perfectly and as expected :+1:

See the IoTeX Devboard on GitHub for a new description of the elements on the board.

More to come in the next days (first firmware on github) !


Amazing job :clap:
Thanks for the update! Can’t wait to see it working!


What is your plan for giving back to the Iotex ecosystem, stakers and community?

Will innovators be able to build extended projects utilising your board?

All the best with your project, live long and prosper.

The page for the Grant Issuance Rules dos not exist.
This link “https://community.iotex.io/t/grant-issuance-rules/3839#milestone-reports-4” does not work for me.


You can try here. We migrated some time last year, or was it a year before…I can’t remember the exact date :sweat_smile:…But some thread might have remained archived after migration