The FemtoTX Motherboard Standard

Update 7-13-25 (Hackaday squashed the original formatting of this Description and hyper links into plaintext & paragraph) #Welcome to a solar system! (why not "my" solar system"? because it's yours! # https://github.com/EI2030/Low-power-E-Paper-OS # Building a consensus on a postage stamp-sized ATX standard with: # 1. Solar Power & Battery Management https://www.tindie.com/products/jaspersikken/solar-harvesting-into-lithium-ion-capacitor/ # 2. MCU & Memory PCB Design: https://www.sparkfun.com/products/15444 "And runs at less than 1mA" https://www.tsmc.com/english/dedicatedFoundry/technology/logic/l_22nm https://www.cmc.ca/globalfoundries-22fdx-fdsoi-22-nm/ # 3. Linux/RTOS software development-- https://github.com/hatonthecat/linux_distro_tests https://github.com/kragen/dernocua/blob/master/text/energy-autonomous-computing.md # 4. E-paper/Reflective Display driver (larger screens sought!) https://www.youtube.com/watch?v=BD4At2-e87E SHARP Memory in Pixel 4.4"

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• computer rendered concept designs

  Giovanni • 09/04/2025 at 16:22 • 0 comments

  

  

  some new concepts (only the last photo seems practical)

• 06-02-2025 Update

  Giovanni • 06/02/2025 at 13:08 • 0 comments

  Vedula has completed synthesis of a ZAP processor (ARMv5T) on an Artix A7!:

  Github repository
  

  Vedula's notes:

  "Please see Save/ dir for Synthesis report.

  Added a separate Readme for convenience."

  syn_timing.rpt
  | Design       : zap_top
  | Device       : 7a75t-csg324
  | Speed File   : -3  PRODUCTION 1.23 2018-06-13
  | Design State : Synthesized

  XC7A75T-1CSG324C

  https://docs.amd.com/v/u/en-US/ds180_7Series_Overview

• Thought Experiment

  Giovanni • 09/21/2024 at 19:34 • 0 comments

  https://github.com/hatonthecat/Solar-Kernel?tab=readme-ov-file#copenhagen 

  The theory, analogy, and metaphor is- solar powered computers are possible, but most have just not realized there was a calculation to be made. (From Copenhagen, 2002, BBC4) 

• Lithium Ion Hybrid Capacitor Circuit & LED Test

  Giovanni • 08/28/2024 at 14:51 • 0 comments

  I successfully tested the Ymin 10mAh, 20 Farad lithium capacitor- it runs continuously and it hasn't been recharged since I received it. Next step is testing a variable resistor, a potentiometer which is pictured in the 1st and 3rd videos to toggle the dimness. I also tested positively a 12V car W5W "dome" LED light that I bought from eBay in 2017 - a 10 pack for $0.99- unsure what kind of voltage it uses (when connected to this breadboard), but similar ones use around 0.2Watts. Green LEDS (not the tinted aspect) use the least power, though using green for everything isn't always preferred.  

• Testing a 20F, 10mAh Lithium Ion Hybrid Capacitor

  Giovanni • 08/26/2024 at 04:06 • 0 comments

  Being so risk-averse when it comes to testing circuits, electricity is easier written about than tested. That said, I try to make time for actually devising miniscule experiments that test at least one or two things. I am also a very slow learner- I tend to accumulate a ton of idle knowledge and rarely organize the information towards something I actually can see a use for testing (and towards developing a more complex test or build!). The terms "move fast and break things" and "fail fast" doesn't interest me, or at least when it comes to testing circuits, as opposed to carpentry or metalworking (which I never do). Not only that, but "move fast and break things" is counterproductive for circuits at best and dangerous at worst. For this video, I was only able to test one thing- voltage. Granted, I also had an unused multimeter that I only tested once in 2021, and had been wanting to get some use out of it. Not to mention the breadboard and solar power managers that I have laying around in a box. But one step at a time- While the breadboard is pictured, it is not tested in this video. That will come next, once I figure out how to wire the minimum circuit necessary to light the red LED.

  A positive result was that the voltage test resulted in a reading of 3.60V, of which the LIC is rated 3.8V. Not sure if that is less than par, or it is just less than 100% charged. Or something like that. The margin of error is somewhere between 0.5-1%, not enough to result in an incorrect reading of 5% margin error:

  |Automatic ranging TRMS 6000 count

  AC voltage: 6V/60V/600V (±1.2% + 5d), 750V (±1.5% + 5d)

  DC voltage 600mV/6V/60V/600V(±0.5% + 5d), 1000V (±1.0% + 5d)

  AC current 6mA/60mA (±1.0% + 10d), 600mA (±1.5% + 10d), 20A (±2.5% + 10d)

  DC current 60μA/6mA/60mA (±0.8% + 10d), 600mA (±1.2% + 10d), 20A (±2.0% + 10d)

  Capacitance: 6nF/60nF/600nF/6μF/60μF/600μF (±3.0% + 5d), 6mF/100mF (±5.0% + 10d)

  Resistance: 600Ω(±0.8% + 10d), 6kΩ/60kΩ/600kΩ/6MΩ(±0.8% + 3d), 600MΩ(±1.2% + 10d)

  Frequency: 100Hz/1000Hz/10kHz/ 100kHz/1MHz/10MHz (±1.0% + 3d)

  Duty ratio: 1%~99% ± (1.0% +2d)

  Temperature: -20℃-100℃ -4℉- 1832℉ (± 1.0% + 3)

  Diode test, Continuity test, Good Sensitivity of NCV sensor

  Full range overloaded protection, Data hold, Live test

  Auto Shutdown: 15 minutes

  Backlight and flashlight|

  https://www.lcsc.com/product-detail/Lithium-Ion-Capacitors_Ymin-SLA3R8L2060813_C970391.html

  Multimeter User UA19B guide: https://drive.google.com/file/d/1uLc5ZH09o1W1XA3oQ490vOcm_m7ylSJ0/view
  

  https://www.amazon.com/gp/product/B08BRG4XN2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

  There are some great tutorials on breadboards:

  https://learn.sparkfun.com/tutorials/how-to-use-a-breadboard/anatomy-of-a-breadboard#:~:text=Terminal%20Strips&text=You%20can%20see%20lots%20of,hide%20under%20the%20plastic%20holes 

  If I haven't posted a project log in a while, it's probably because I'd like to have something more substantial to showcase in a video than a single test. But I'm ok with that too.

  Note: the 9V multimeter battery is being replaced very soon! It will be interesting to discover whether the low battery level was causing a 5-6% measurement error rate, which would suggest it is actually 3.8V...
  

  ----

  An English version of the data sheet can be viewed here:
  

  https://en.sekorm.com/doc/2768518.html
  

  

  "The SLA3R8L2060813 from Shanghai Yongming Electronic is a Supercapacitor with Capacitance 20000 mF, Voltage Rating 3.8 V, Equivalent Series Resistance 500 mOhms, Temperature Operating Range -40 to 85 Degree C. Tags: Through Hole. More details for SLA3R8L2060813 can be seen below.
  

  Product Specifications

  Product Details

  • Part Number SLA3R8L2060813
  • Manufacturer Shanghai Yongming Electronic
  • Description 20000 mF,...

  Read more »

• Steve Jobs' 1984 Macintosh, & Why Designing a Solar Powered Laptop integrates New Tech the same way.

  Giovanni • 10/02/2023 at 19:54 • 0 comments

• Review of project status (and some history of telecommunications)

  Giovanni • 10/01/2023 at 02:48 • 0 comments

• Adapted Pi-Top for solar panel by replacing display cable outlet for DC cable

  Giovanni • 03/20/2021 at 13:17 • 0 comments

  Was able to fit a 5" screen in Pi-Top v3, thus considering use as a cyberdeck instead of main panel.

• Solar powering Ambiq Micro Apollo3

  Giovanni • 03/17/2021 at 16:14 • 0 comments

• Powering the 5mW Artemis Nano fully on a 10.5 Phillips LED

  Giovanni • 03/09/2021 at 05:04 • 0 comments

  Got my Artemis Nano to power on completely with a 10.5W LED, far less than the 45W Cowboy Studio CFL I was using with the 2V, 160mAh panel in my previous log . Since the bluetooth LED is is blinking, it must be using around 5mW, which is probably not very efficient, although it is the only way I can connect [using an Adafruit Universal USB / DC / Solar Lithium Ion/Polymer charger w/ TI BQ24074) the 5W panel to the USB-C input of the Artemis Nano at the moment. Some efficiency loss is likely, since it travels through the 500mA boost converter.

  

  Later I put the lampshade back on the Philips and was able to get a red LEDd, but it took a while for current to flow through the entire circuit. With some efficiency improvements (i.e soldering the 500mV boost and panel placement), it is very likely that the Artemis Nano can be powered in a more ambient condition (i.e not a bulb directly on the panel as in the above photo.)

  I’ll also try my Powerfilm Dev-in-Basic w/ BQ25570 development kit sometime.

View all 15 project logs

• 1

  Step 1

  These are not build instructions but build concepts.

  Goal #1: Power a Sparkfun Artemis board on 4 Powerfilm LL200-2.4-75or 3-37 (x2 or x4): 
  

  

  by using: 

  1. Sparkfun Artemis board https://www.sparkfun.com/products/15443

  and

  https://www.powerfilmsolar.com/products/development-kits/solar-development-kit  (DEV-BASIC)

  uses BQ25570 and includes (2) LL200-3-37 Indoor Solar Panel with 6” leads

  or https://www.powerfilmsolar.com/products/development-kits/aem-pf-evk-solar-development-kit-with-e-peas-pmic 

  uses AEM10941 harvester:

  • AEM-PF-EVK Dev Kit PCBA (and includes (2) LL200-2.4-37 Indoor Solar Panel with leads) 
  • a battery can be used in place of the supercapacitor. This image was used to demonstrate the panels can be wired in parallel. Earlier in the video they use a 40mah battery, which could be used here, or a larger one (100mah), for example.

  Additional panels can be purchases separately from Digikey & Mouser. Other BQ25570 chargers include Mikroe-2814:

  https://www.arrow.com/en/products/mikroe-2814/mikroelektronika?gclid=Cj0KCQiAmfmABhCHARIsACwPRADBziDNW74RhE4C6A4Bf8bEsCRlMSrswfLfvO-a-cDouq-HHLcOQ2MaAhDSEALw_wcB

  and off-brand BQ25570: https://www.ebay.com/itm/184366178954 

  A Tindie seller for AES10941 https://www.tindie.com/products/jaspersikken/solar-harvesting-into-li-ion-battery/

  Demo: 

  By accomplishing this goal, it can be demonstrated that not just a bluetooth sensor, but a microcontroller capable of running GUI-based applications on a number of solar panels inside continuously, without relying on sleep programming. The goal of this is to be a computer that one can access and see a stream of emails incoming, and not it have to shut off for long boot up times.

  Jasper Sikken, who sells an AEM10941 harvester on Tindie, has said on his project page (Thank you!): https://hackaday.io/project/159139-tiny-solar-energy-module-tsem :

  "Jasper Sikken wrote 4 hours ago
  

  You seem to understand my calculations to estimate the amount of daily harvested energy. The AEM10941 input voltage range is max 5V. You need to make sure that the open circuit voltage does not exceed 5V. That often means you need to select 4V or less NOMINAL voltage. Either you put 1 or more 4V solar panels in parallel or put a few lower voltage cells in series. Note that a partial shade on a series string causes the whole string to malfunction. Also note that AEM10941 efficiency drops with solar panel voltage below 1V. So a tradeoff is to select about 2.0V nominal voltage and if you want more power you add more in parallel"

  Additional Powerfilm Dev-Kit Review: 

• 2

  Step 2. Add a display​

  Power an e-ink or reflective display and the Artemis board connected to the Artemis board's SPI pins using 4-6 panels.

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