Arachnio Due

An Arduino Micro variant with an ARM Cortex M4 and onboard WiFi

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So, there's now an official Arduino board coming out, the MKR1000, that accomplishes essentially everything I wanted to do with the Arachnio. Therefore, I am now releasing all of my work on the project to date for anyone who would like to use it. I will not be doing further development on it, and will instead be focusing my efforts on the Multispork and Hackerboat.

I am thinking about putting together versions of the ArachnoProto, Arachnode, and the ArachnoMoto for the MKR1000 when it's released.

The Arachnio Due is the first Arduino variant with both an ARM Cortex M4 and an on-board ESP8266. Functionally, it's an Arduino Micro variant with an Atmel SAM4S and an ESP8266 integrated directly on the board. Along with the core Arachnio, I've also designed two companion boards, the Arachnode and the ArachnoProto.

Here's what makes the Arachnio Due special:

  • Integrated WiFi -- No extra parts to buy or integrate -- just load an easy-to-use library and connect to the Internet! The ESP8266EX WiFi chip on the Arachnio works beautifully with the Arduino core.
  • ARM Cortex M4 Power -- The Arachnio Due takes advantage of the power of Atmel's ATSAM4S2AA running at 120 MHz. It has 128 kB of Flash, 64 kB of SRAM, a 1 MSPS A/D converter, hardware floating point support, a built-in RTC, PWM, I2C, and SPI
  • Small and light -- The Arachnio is only 50 mm long, 18 mm wide, and weighs less than 10 grams with headers installed.
  • Rugged -- Due to its small size, light weight, and the robustness of the SAM4S processor, it's hard to kill.
  • Low power draw -- In deep sleep with the power LED removed, current consumption is below 50 microamps on a single Li-Po cell.
  • Arduino Micro pinout -- The Arachnio uses the same pinout as the Arduino Micro and is only very slightly larger in order to accommodate the integrated antenna.
  • Breadboard compatible -- Standard 0.1" headers enable you to plug directly into a breadboard for easy prototyping.
  • Fully open source -- everything including the board layout and the network stack is open source.

In order to make it even easier to get up and running, we're coming out with two expansion boards immediately -- the ArachnoProto and the Arachnode.

The ArachnoProto is a prototyping expansion board for the Arachnio. It has a reset button, a general purpose button, two LEDs, and a JTAG header for programming and debugging the SAM4S.

The Arachnode is perfect for building remote sensor and network nodes. It integrates a solar Li-Po battery charge, a micro SD card, and an optional Atmel cryptography module in order to provide a platform for building lightweight and inexpensive webs of Arachnios for remote sensing and other purposes.

Technical Specs

Arachnio Due

  • Atmel SAM4S2AA ARM Cortex M4 processor
  • ESP8266EX WiFi with printed antenna
  • 128 kB flash storage on the SAM4S
  • 16 kB SRAM
  • 4 MB SPI firmware flash for the ESP8266EX
  • 3.3V operation
  • 120 MHz clock speed
  • 24 digital I/O (14 dedicated)
  • 8 analog I/O (6 dedicated)
  • 8 PWM channels
  • SPI, I2C, and 2 UARTs available (One UART shared with ESP8266EX)
  • LED indicators for Power, USB TX/RX, D13
  • Built-in real time clock


  • Two LEDs
  • Reset button
  • General purpose button
  • JTAG header
  • FTDI cable header for independent programming of the ESP8266
  • Two 2" x 1" prototyping areas
  • Option to use standard headers, stacking headers, or bottom-entry headers for extra low profile.


  • BQ24210 solar battery chargerBattery fuel gauge
  • Solar panel voltage monitor
  • micro SD card slot
  • Optional ATAES132 crypto module
  • Option to use standard headers, stacking headers, or bottom-entry headers for extra low profile.

Suggested Applications

The Arachnio Due is an incredibly versatile board, suitable for all types of Internet of Things applications. Here are a few that we've thought about:

  • Deployable sensors (as seen in our video) -- monitor a room, your garden, or anything else.
  • Mobile robotics -- use it as a remote control or as the brains of any robot.
  • Distributed LED lighting -- perfect for controlling mood lighting or light shows.
  • Home automation -- wire it up to power control hardware to control your lights, climate control, or appliances.

Hardware & Software Progress

  • 1 × SAM4S2AA Microprocessors, Microcontrollers, DSPs / ARM, RISC-Based Microcontrollers
  • 1 × ESP8266 WiFi SoC
  • 1 × ATAES132 (on the Arachnode) Crypto module
  • 1 × BQ24210 (on the Arachnode) Solar battery charger

  • Draft Kickstarter

    Pierce Nichols11/22/2015 at 06:57 0 comments

    I've been working hard on the code for this and getting the Kickstarter put together. In order to avoid competing with the many holidays at this time of the year (and give myself some more time to put together the video), I've decided to push the Kickstarter launch back to the beginning of January. In the meantime, check out the draft Kickstarter. I'd love to hear all your feedback on it.

  • Seattle Mini Maker Faire 2015

    Pierce Nichols09/21/2015 at 02:09 0 comments

    We took the Arachnio Due to the Seattle Mini Maker Faire in the form of a couple of sumo bots based on Jeremy's wifibot project. The bots, with a little maintenance, lasted most of the weekend, which was awesome. Dozens of people took the opportunity to drive the bots and challenge each other in our robosumo ring over the weekend.

    We'll get pictures and video up in a couple of days once we've recovered from the weekend. In order to get notifications about the Arachnio Due and a heads-up when our Kickstarter goes live, please sign up for our email list.

  • It's Alive!

    Pierce Nichols09/10/2015 at 00:03 0 comments

    After some entertaining yak shaving, I can now compile the Blink sketch and load it onto a prototype Arachnio Due with bossac. I made the not-entirely-awesome decision to place the pin 13 LED right next to the power light, so it's not as clear as I'd like, but you can see the green LED blinking right next to the steady blue.

    The yak shaving entailed adding SAM4S support to bossac. First challenge was configuring mingw to compile it, which mostly just meant futzing around with my path. The only reason it was challenging is because I was convinced there must be something more to it, so I investigated that rather than doing the trivial thing.

    Luckily, there has been some motion towards adding SAM4S support, so I just built from that and made sure that the SAM4S2 was on the list of supported architectures. You can check out my modifications here: I've submitted it as a PR to the bossa mainline, so hopefully it gets picked up and I don't have to ship special tools with the Arachnio Due package.

    Thibaut has been doing some really awesome stuff on the core, which is the really big part of this puzzle. It looks like I will be able to get the Arachnio sumo bots up and running for Seattle Mini Maker Faire the weekend after next!

  • New pictures!

    Pierce Nichols09/02/2015 at 01:00 0 comments

    I've just added some pictures of the new prototypes. The assembled Arachnio Due passed its smoke test, and I'm helping Thibaut get the core up to the point where I can start testing more functions.

  • Arachnio Due

    Pierce Nichols08/18/2015 at 16:42 0 comments

    The Arachnio Due is finally coming together. The biggest boost I've received over the past few months is from Thibault Viard, who is currently porting the Arduino core to work with the Atmel SAM4S series, which gives me access to a much better processor. You can check out his code here:

    I've been working more on porting the Arduino WiFi library to work with the AT command mode of the ESP8266. I tossed out my earlier attempts and restarted it as a driver-level re-write. I've implemented everything but UDP, but I haven't tested much of it yet. You can check it out here:

    I am hoping to unveil it publicly as the Seattle Mini MakerFaire in September, and go live on Kickstarter soon after.

  • A new direction -- Arachnio Due

    Pierce Nichols05/05/2015 at 17:09 0 comments

    Well, the Kickstarter flamed out a bit short of half way funded. This makes me sad, but I have a new plan.

    The most common question I received was asking why the Arachnio had an AVR rather than an ARM... and the most common comment was criticizing me for not using one. I took that to heart, and I'm in the process of designing a new version of the Arachnio, the Arachnio Due. It will feature a SAM3S series microcontroller running at 64 MHz for a major boost in computing power at no change in cost.

    I'm working on the layout right now and I will be posting more updates as they become available.

  • Arachnode & ArachnoProto new prototypes

    Pierce Nichols04/20/2015 at 03:03 0 comments

    Late last week, I got the prototypes for the latest revisions of the Arachnode and the ArachnoProto. I'll be getting another spin of the core Arachnio late next week to roll in some things that I found I wanted with the ESP8266 connections during testing and development. In particular, I cut out a couple of unnecessary programming connections and added a jumper to allow the 32u4 to reset the ESP8266 if necessary.

    Today was a gorgeous day here in Seattle, so I took some pictures outside. It turns out natural sunlight makes everyone, even me, a better photographer.

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AVR wrote 05/18/2015 at 04:18 point

where can I view the source files for the design? I am intrigued by your integrtated ESP8266 topology and I would very much like to learn from your design. Thanks.

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Pierce Nichols wrote 04/13/2015 at 22:32 point

Thank you! You are correct about the header, of course -- I guess I have it embedded in my brain because of the Arduino. I'll make sure the boards go out with correct silkscreen at least. :)

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Tachyon wrote 04/12/2015 at 23:52 point

Great idea! It's about time someone did this.

One tiny nit pick, on the Atmel chips it's called an ISP header, not an ICSP header. Don't feel bad, the Arduino guys got it wrong too.

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