D-MARK is a versatile, open-source development board designed to leverage the STM32F070RB ARM microcontroller’s unbeatable price-to-performance ratio. It comes with the open-source D-MARK Script Interpreter (DMSI) firmware, which means you don’t need to be a programmer to use it. Just save a few lines of text to a microSD card, slot it in, and watch D-MARK go to work.

Unlike many development kits, D-MARK includes a curated set of inputs and outputs that were carefully chosen to facilitate real-life applications and to prevent you from having to re-invest in hardware. Whether you’re a professional programmer or an electronics enthusiast, D-MARK might very well be the fastest and most economical way for you to begin exploring the world of ARM microcontrollers.

Features

• Sensor and controller functionality in a single board
• Inputs and outputs sufficient for typical controller-related applications
• Field-ready hardware that can handle real-world applications
• No IDE and no need to program or compile code
• Gets you up and running with ARM in minutes rather than hours or days
• Bridges the gap between education and implementation
• Open hardware driven by open-source software
• Reduces both hardware and software development time

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1. Auxiliary Power Output - parallel to the Main Power Connector (see #4, below)
2. 1x MOSFET Output Connector - a dedicated output to drive a DC fan or similar load
3. 3x MOSFET Output Connectors - the same function as #2, above
4. Main Power Connector - accepts 9 - 24 VDC power supply
5. Piezo Speaker Output
6. 3x Relay Outputs - with connectors
7. Fuse - accepts a blade fuse similar to those used in cars (provided)
8. 2x SenseLog Port - a custom sensors connection using single-wire communication
9. Servo Header - usable with typical RC servos and powered by external power
10. Auxiliary ATTINY84A MCU - pre-programmed to work as a transparent input/output
11. ARM STM32F070RB MCU - running at 48 MHz with built-in DMSI
12. Micro SD Card - for running user scripts
13. Stepper Motor Module Header - headers for docking a stepper motor module
14. SWD header - for programming the STM32F070RB using a standard SWD interface (such as the ST-LINK V2 or V3)
15. 4x Digital Inputs - accepts mechanical or optical switches and each channel is pulled up and current-limited
16. USB Connector - served as a virtual COM port output for debugging and other purposes
17. UART Header - similar to the USB Connector above, but without an interface IC
18. Display Port - direct support for OLED displays using the SH1106 driver
19. 3x Analog Sensor Connectors - inputs for LDR, NTC, and analog voltage input at 0-30 VDC
20. Reset Button
21. Logic Power Source Selection - can be provided internally or externally via 5 V USB
22. Boot Mode Selection - opened for normal use, shorted for use with a boot loader

Technical Specifications

Inputs

• 4x Digital inputs
• 1x LDR sensor
• 1x NTC temperature sensor
• 1x 0-30 VDC analog voltage

Outputs

• 4x MOSFET outputs (rated for 12 V and 3.5 A continuous without heaksink)
• 3x SPST relays (5 A contact)
• 1x Stepper motor driver socket
• 1x RC servo output
• 1x Piezo passive speaker

Communication

• 1x USB Type-B female
• 2x USB Type-A female
• 1x microSD card socket
• 1x UART
• 1x 6-pin I²C OLED display socket
• 1x SWD programming & debug port

Others

• 1x 10 A blade fuse
• 1x Tactile reset switch

Comparisons

Note
* = Maximum 12 V and 3.5 A continuous without heatsink

Product Accessories

Stepper Motor Driver Module

This module slots into the D-MARK Controller Board is capable of driving 4- to 8-wire step motors up to 2 A. Current limiting can be adjusted using the on-board trimpot.

Programmer Clamp

This clamp can be used with any AVR programmer to program the ATTiny84A transparent line driver. You only need to do this if you want to use a custom communications protocol between the STM32F070RB and SenseLog ports.

Support & Documentation

You can find all of the documentation related to this project in our GitHub repository. Feel free to modify, extend, and adapt it to suit your requirements! And, if you have a question, please feel free to reach out to us using the Ask a technical question on our campaign page.

Manufacturing Plan

PCB design, assembly, and testing will all be done in-house here in Nonthuri, Thailand. For the sake of traceability and quality assurance, we will order our PCBs and parts from reliable, RoHS- and ISO-certified companies in the USA and China. For assembly, we will be using the custom pick-and-place machine we built for our previous project, PowerEver. Thanks to hardware add-ons and fine-tuning, it currently has a placement accuracy of better than 0.2 mm. Below is a demonstration of this machine placing 64-pin, 0.5 mm pitch ARM STM32F070RB microcontrollers:

Fulfillment & Logistics

When manufacturing and testing are complete, we will send all D-MARK boards 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

We have worked hard to minimize manufacturing risks and to avoid delivery delays. The common, discrete electronic components we require are all well stocked, and sourcing for other critical parts has already been arranged. Should we encounter unexpected challenges or delays, we will immediately inform backers by way of a campaign update.