The Open Source Autarkic Motherboard

A solar-powered, Raspberry Pi-like Board idea that runs on 5mW

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Welcome to a solar system! Tentatively titled Minitel 2W (2.0, Wireless)

Building a consensus on a credit card sized ATX standard with:

1. Solar Power & Battery Management

2. MCU & Memory PCB Design:

3. Linux/RTOS software development--EPOC/EKA2?

4. E-paper/Reflective Display driver (larger screens sought!) SHARP Memory in Pixel 4.4" RLCD LPM044M141A


Brainstorming Draft Specs to develop "FemtoTX" and "AttoTX" form factor

"FemtoTX" (fTX) could be used for tablets and laptops, whereas "AttoTX" aTX) could be for cell phones, or at least small enough to be in a keycard or usb drive. Though there could be an overlap so that attoTX can also fit on a femtoTX mounting holes (similar to mini-ITX fitting on 4 of 9 Micro holes.


from: (chosen for easy reference/continuity, rather than arbitrarily small form factor concept)

"The Mobile-ITX form factor was announced by VIA Technologies at Computex in June, 2007. The motherboard size of first prototypes was 75 × 45 mm (3.0 × 1.8 in).[2] The design was intended for ultra-mobile computing such as a smartphone or UMPC."


60mm is 2.3622" and that might be too large for a mobile phone at least for a square dimension. 40x40mm = 1.57x1.57" and might be simpler for a smaller form factor, but perhaps too small for femtoTX and too large for attoTX.

The Sparkfun Nano, for example (see pictures) is 49mmx21mmx7mm (1.92"x0.82"x0.27"): Narrow and thin enough to fit in a phone and long enough for additional headers. A boxier one would not as flexible with most cell phones (as 1.9 wide would leave little space for the side of the cell phone. Two mounting holes could be used, however, and doubling the width to 50x50mm or 49x49mm might be ideal for femtoTX, which could have the same distance between mounting holes for all 4.

By comparison, the Raspberry Pi 3-4 is around 85x56x17mm (l x w x h):

Single-core 700MHz
ARM Cortex-A53
Quad-core (3B 1.2GHz, 3A+/3B+ 1.4GHz)
ARM Cortex-A72
Quad-core 1.5GHz
GPUBroadcom VideoCore IV@400MHzBroadcom VideoCore IV@500MHz
RAM512MB512MB1GBChoice of 2GB/4GB/8GB
USB1x micro USB1x USB2.04x USB2.02x USB2.0 + 2x USB3.0
BluetoothN/ABluetooth 4.1Bluetooth 4.2Bluetooth 4.1Bluetooth 4.2Bluetooth 5.0
WiFiN/A802.11 b/g/n3B: 802.11 b/g/n, others: 802.11 b/g/n/ac 2.4GHz/5GHz dual band
EthernetN/A100Mbps300Mbps (USB)1000Mbps
Power InputMicro USB (5V 2.5A)USB Type-C (5V 3A)
Dimensions65 × 30 x 5 mm65 × 56 mm85 x 56 x 17 mm

The PicoITX (, a common embedded format, is slightly larger than the newer Raspberry Pis, but not by much: 

ROCK Pi E: 56 x 65 mm, or 2.5 x 2.2 in

(2020) Radxa’s latest single-board computer is a tiny system that measures just 65mm x 56mm (2.6″ x 2.2″). It’s called the Rock Pi E and it features a Rockchip RK3328, support for up to 2GB of RAM, and an eMMC socket and microSD card reader that you can use for storage."

  • "The measurement is 1.7 x 1.7 inches (38.1 x 38.1 mm)."

Having used a RockPi S, it seems acceptably small without being too wide. Whether it could accommodate...

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semi-accurate Claremont.pdf

2012 article, best detail of application processor chip

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e64 wrote 07/01/2024 at 18:55 point

please add more ram 512K is ok for start.

and meybe a / Lora network for emergency communications

  Are you sure? yes | no

Giovanni wrote 07/01/2024 at 20:55 point

  Are you sure? yes | no

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