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michka:research:microbial_fuel_cells:cardiff6 [2017-09-17 10:58] – michkamichka:research:microbial_fuel_cells:cardiff6 [2017-09-17 14:37] (current) – michka
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 **[[http://www.zprod.org|Paul Granjon]] & [[http://michkamelo.wordpress.com|Michka Mélo]], May 10th-13th, 2017, Cardiff** **[[http://www.zprod.org|Paul Granjon]] & [[http://michkamelo.wordpress.com|Michka Mélo]], May 10th-13th, 2017, Cardiff**
  
-{{>https://www.flickr.com/photos/foam/37278347985/  ?maxwidth=800}}\\+{{>http://www.flickr.com/photos/foam/37278347985/  ?maxwidth=600}}\\
  
 ====0. Abstract==== ====0. Abstract====
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 ====1. Home-made Microbial Fuel Cells (MFCs)==== ====1. Home-made Microbial Fuel Cells (MFCs)====
 +
 +{{>http://www.flickr.com/photos/foam/36440367724/  ?maxwidth=600}}\\
  
 ===1.1 Material list=== ===1.1 Material list===
  
    * Graphite powder (Inoxia Ltd, via Ebay)    * Graphite powder (Inoxia Ltd, via Ebay)
 +
 +{{>http://www.flickr.com/photos/foam/37087494326/  ?maxwidth=400}}\\
 +
    * Graphite rods (scholar stuff)    * Graphite rods (scholar stuff)
 +
 +
 +{{>http://www.flickr.com/photos/foam/37087470986/  ?maxwidth=400}}\\
 +
    * Wool (old blanket)    * Wool (old blanket)
 +
 +{{>http://www.flickr.com/photos/foam/37087483846/  ?maxwidth=400}}\\
 +
    * FeO2 powder for ceramicists (via Ebay)    * FeO2 powder for ceramicists (via Ebay)
 +
 +
 +{{>http://www.flickr.com/photos/foam/37087498876/  ?maxwidth=400}}\\
 +
    * Inox wire (Amazon, for DIY jewel-makers)    * Inox wire (Amazon, for DIY jewel-makers)
 +
 +{{>http://www.flickr.com/photos/foam/37087499966/  ?maxwidth=400}}\\
 +
    * Food tupperwares with clipping lids (Amazon)    * Food tupperwares with clipping lids (Amazon)
 +
 +{{>http://www.flickr.com/photos/foam/36440366634/  ?maxwidth=400}}\\
  
 ===1.2 MFC composition=== ===1.2 MFC composition===
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 Layer by layer, from bottom to top, we have : Layer by layer, from bottom to top, we have :
-   * serpent-shaped (about 10 crossings across the tupperware) inox wire, with a vertical section insulated with the black (-) plastic cover of a reclaimed multi-fiber wire +   * serpent-shaped (about 10 crossings across the tupperware) inox wire, with a vertical section insulated with the black (-) plastic cover of a reclaimed multi-fiber wire 
 + 
 +{{>http://www.flickr.com/photos/foam/37087499966/  ?maxwidth=400}}\\  
 + 
      * 1-cm-thick layer of graphite powder, mixed with water      * 1-cm-thick layer of graphite powder, mixed with water
 +
 +{{>http://www.flickr.com/photos/foam/36440361484/  ?maxwidth=400}}\\ 
 +
      * (soaked) wool membrane      * (soaked) wool membrane
 +
 +{{>http://www.flickr.com/photos/foam/36880233410/  ?maxwidth=400}}\\ 
 +
      * mud      * mud
 +
 +{{>http://www.flickr.com/photos/foam/37087491486/  ?maxwidth=400}}\\ 
 +
      * (soaked) wool membrane      * (soaked) wool membrane
-     * serpent-shaped (about 10 crossings across the tupperware) inox wire, with  + 
-     * 1-cm-thick layer of graphite powder, mixed with water, with a vertical section insulated with the grey (+) plastic cover of a reclaimed multi-fiber wire+{{>http://www.flickr.com/photos/foam/37087500946/  ?maxwidth=400}}\\  
 + 
 +     * serpent-shaped (about 10 crossings across the tupperware) inox wire, with a vertical section insulated with the grey (+) plastic cover of a reclaimed multi-fiber wire
        * A small bit of red mono-fiber wire is woven around the (+) electrode wire to clearly distinguish it from the (-) electrode wire        * A small bit of red mono-fiber wire is woven around the (+) electrode wire to clearly distinguish it from the (-) electrode wire
 +     * 1-cm-thick layer of graphite powder, mixed with water 
 +
 +{{>http://www.flickr.com/photos/foam/36440362364/  ?maxwidth=400}}\\ 
 +
      * both electrode wires are interwoven on the top to avoid the top (+) electrode to sink away from oxygen      * both electrode wires are interwoven on the top to avoid the top (+) electrode to sink away from oxygen
 +
 +{{>http://www.flickr.com/photos/foam/37087471336/  ?maxwidth=400}}\\ 
 +
      * a small opening is cut on side of the lid with a cutting clamp to let the electrode wires go through towards the circuit      * a small opening is cut on side of the lid with a cutting clamp to let the electrode wires go through towards the circuit
      * the lid is drilled with       * the lid is drilled with 
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    * 1-cm-thick layer of graphite powder, mixed with water    * 1-cm-thick layer of graphite powder, mixed with water
    * (soaked) wool membrane    * (soaked) wool membrane
-   * 2 spoons of FeO oxide thoroughly mixed in the mud+   * mud containing 2 spoons of FeO oxide thoroughly mixed 
 + 
 +{{>http://www.flickr.com/photos/foam/37087471466/  ?maxwidth=400}}\\ 
    * (soaked) wool membrane    * (soaked) wool membrane
    * serpent-shaped (about 10 crossings across the tupperware) inox wire, with     * serpent-shaped (about 10 crossings across the tupperware) inox wire, with 
    * 1-cm-thick layer of graphite powder, mixed with water, with a vertical section insulated with the grey (+) plastic cover of a reclaimed multi-fiber wire    * 1-cm-thick layer of graphite powder, mixed with water, with a vertical section insulated with the grey (+) plastic cover of a reclaimed multi-fiber wire
 +
 +{{>http://www.flickr.com/photos/foam/37278348485/in/album-72157686272755070/  ?maxwidth=400}}\\
 +
      * A small bit of red mono-fiber wire is woven around the (+) electrode wire to clearly distinguish it from the (-) electrode wire      * A small bit of red mono-fiber wire is woven around the (+) electrode wire to clearly distinguish it from the (-) electrode wire
    * both electrode wires are interwoven on the top to avoid the top (+) electrode to sink away from oxygen    * both electrode wires are interwoven on the top to avoid the top (+) electrode to sink away from oxygen
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 Layer by layer, from bottom to top, we have : Layer by layer, from bottom to top, we have :
-   * graphite rods cut to fit in the tupperware, and woven together with inox wire, with a vertical section insulated with the black (-) plastic cover of a reclaimed multi-fiber wire +   * graphite rods cut to fit in the tupperware, and woven together with inox wire, with a vertical section insulated with the black (-) plastic cover of a reclaimed multi-fiber wire 
 + 
 +{{>http://www.flickr.com/photos/foam/37278348745/  ?maxwidth=400}}\\ 
 +{{>http://www.flickr.com/photos/foam/37278348145/  ?maxwidth=400}}\\ 
    * mud    * mud
-   * graphite rods cut to fit in the tupperware, and woven together with inox wire, with a vertical section insulated with the grey (+) plastic cover of a reclaimed multi-fiber wire. + 
 +{{>http://www.flickr.com/photos/foam/37278350655/  ?maxwidth=400}}\\ 
 + 
 +   * graphite rods cut to fit in the tupperware, and woven together with inox wire, with a vertical section insulated with the grey (+) plastic cover of a reclaimed multi-fiber wire. 
 + 
 +{{>http://www.flickr.com/photos/foam/37087471716/  ?maxwidth=400}}\\ 
 + 
      * A small bit of red mono-fiber wire is woven around the (+) electrode wire to clearly distinguish it from the (-) electrode wire      * A small bit of red mono-fiber wire is woven around the (+) electrode wire to clearly distinguish it from the (-) electrode wire
    * both electrode wires are interwoven on the top to avoid the top (+) electrode to sink away from oxygen    * both electrode wires are interwoven on the top to avoid the top (+) electrode to sink away from oxygen
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    * 2 spoons of FeO oxide thoroughly mixed in the mud    * 2 spoons of FeO oxide thoroughly mixed in the mud
    * graphite rods cut to fit in the tupperware, and woven together with inox wire, with a vertical section insulated with the grey (+) plastic cover of a reclaimed multi-fiber wire.     * graphite rods cut to fit in the tupperware, and woven together with inox wire, with a vertical section insulated with the grey (+) plastic cover of a reclaimed multi-fiber wire. 
 +
 +{{>http://www.flickr.com/photos/foam/37087471856/  ?maxwidth=400}}\\
 +
      * A small bit of red mono-fiber wire is woven around the (+) electrode wire to clearly distinguish it from the (-) electrode wire      * A small bit of red mono-fiber wire is woven around the (+) electrode wire to clearly distinguish it from the (-) electrode wire
    * both electrode wires are interwoven on the top to avoid the top (+) electrode to sink away from oxygen    * both electrode wires are interwoven on the top to avoid the top (+) electrode to sink away from oxygen
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    * serpent-shaped (about 10 crossings across the tupperware) inox wire, with a vertical section insulated with the black (-) plastic cover of a reclaimed multi-fiber wire     * serpent-shaped (about 10 crossings across the tupperware) inox wire, with a vertical section insulated with the black (-) plastic cover of a reclaimed multi-fiber wire 
    * 1-cm-thick layer of graphite powder, mixed with tiny bits (about 1 mm long) of wool and water    * 1-cm-thick layer of graphite powder, mixed with tiny bits (about 1 mm long) of wool and water
 +
 +{{>http://www.flickr.com/photos/foam/37278348645/in/album-72157686272755070/  ?maxwidth=400}}\\
 +{{>http://www.flickr.com/photos/foam/37087492846/in/album-72157686272755070/  ?maxwidth=400}}\\
 +
    * (soaked) wool membrane    * (soaked) wool membrane
    * mud    * mud
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 ====2. Power Harnessing System==== ====2. Power Harnessing System====
 +
 +{{>http://www.flickr.com/photos/foam/37087481986/in/album-72157686272755070/  ?maxwidth=400}}\\
  
 ===2.1 Joule Thief=== ===2.1 Joule Thief===
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    * Paul is now trying a new design, where he tries to use the short burst allowed by the 1381E (few fractions of a volt of supercap voltage difference between opening and shutting down) to power the BBC microbit enough so that it can open the gate of another transistor (also 2N3904) to power itself directly from the 2.7V 1F supercap. Instead of the BBC microbit shutting down when the 1381 shuts down (around 0.2 V below its light-up voltage), it will shut down when the voltage provided by the supercap is too low to power the BBC microbit. The BBC microbit will then shutdown, closing the gate of the 2N3904 it controls, and thereby allowing the supercap to charge again.    * Paul is now trying a new design, where he tries to use the short burst allowed by the 1381E (few fractions of a volt of supercap voltage difference between opening and shutting down) to power the BBC microbit enough so that it can open the gate of another transistor (also 2N3904) to power itself directly from the 2.7V 1F supercap. Instead of the BBC microbit shutting down when the 1381 shuts down (around 0.2 V below its light-up voltage), it will shut down when the voltage provided by the supercap is too low to power the BBC microbit. The BBC microbit will then shutdown, closing the gate of the 2N3904 it controls, and thereby allowing the supercap to charge again.
      * IT WORKED !!! (on a fully charged supercapacitory rating at 2.7 V 1 F)      * IT WORKED !!! (on a fully charged supercapacitory rating at 2.7 V 1 F)
-     * (Circuit scheme is drawn in “nice designs notebook”, to be scanned). 
  
    * When connecting a small motor to the BBC microbit on this same circuit, we have about 10 seconds of full motor operation on the 1F 2.7V supercap.    * When connecting a small motor to the BBC microbit on this same circuit, we have about 10 seconds of full motor operation on the 1F 2.7V supercap.
 +
 +{{>http://www.flickr.com/photos/foam/37278352735/in/album-72157686272755070/  ?maxwidth=400}}\\
  
    * When connecting the input to the charge pump S882-Z, itself connected to a 0.3 V power supply (equivalent to 1 MFC), Paul observed that it would charge of 0.01 V every minute, which means that it would take 90 minutes to charge the supercap from his 1.8 V minimum (when the BBC microbit shuts down) to its 2.7 V maximum charging voltage. However, with multiple MFC in series, it might take less time.    * When connecting the input to the charge pump S882-Z, itself connected to a 0.3 V power supply (equivalent to 1 MFC), Paul observed that it would charge of 0.01 V every minute, which means that it would take 90 minutes to charge the supercap from his 1.8 V minimum (when the BBC microbit shuts down) to its 2.7 V maximum charging voltage. However, with multiple MFC in series, it might take less time.
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 ===2.5 Charging a supercap from Mudwatts=== ===2.5 Charging a supercap from Mudwatts===
 +
 +{{>http://www.flickr.com/photos/foam/37278360765/in/album-72157686272755070/  ?maxwidth=400}}\\
  
 ==2.5.1 Overnight parallel post-chip supercap charge== ==2.5.1 Overnight parallel post-chip supercap charge==
  
-=2.5.1.1 Results=+//Results//
  
    * We connected our three (inequally) working Mudwatts in parallel to a 0.22 F 2.5 V supercap.    * We connected our three (inequally) working Mudwatts in parallel to a 0.22 F 2.5 V supercap.
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    * About one hour after the start of the experiment, it was charged at 0.25 V.    * About one hour after the start of the experiment, it was charged at 0.25 V.
    * After letting it overnight, it was only charged at 1.9 V, and we could not see any charging activity with a typical multimeter.    * After letting it overnight, it was only charged at 1.9 V, and we could not see any charging activity with a typical multimeter.
-   * We would have expected a charge reaching 2.5 V, which is the maximum rating of the supercap…+   * We would have expected a charge reaching 2.5 V, which is the maximum rating of the supercap...
  
-=2.5.1.2 Consequences on the PHS design=+//Consequences on the PHS design//
   
-   * … it is actually a limitation of the S882-Z chip, which will only charge up to 1.8 V (according to the datasheet).+   * ...it is actually a limitation of the S882-Z chip, which will only charge up to 1.8 V (according to the datasheet).
    * This means that our supercap will only charge up to 1.8 V, which is not sufficient to power the BBC microbit    * or even open the 1381 voltage detector, which opening rising voltage limit is at 2.4 V.    * This means that our supercap will only charge up to 1.8 V, which is not sufficient to power the BBC microbit    * or even open the 1381 voltage detector, which opening rising voltage limit is at 2.4 V.
    * This means that we need another boost converter or charge pump using the 1.8 V charged supercap energy to bring it up to 2.4 V to activate the 1381 voltage detector, and then power the BBC microbit enough to open the gate of the 2N3904 feeding itself longer directly from the energy source.    * This means that we need another boost converter or charge pump using the 1.8 V charged supercap energy to bring it up to 2.4 V to activate the 1381 voltage detector, and then power the BBC microbit enough to open the gate of the 2N3904 feeding itself longer directly from the energy source.
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      * Could the second boost converter/charge pump replace the need for a post-Beam circuit (1381 voltage detector + transistors), by directly powering the BBC microbit in the appropriate conditions ?      * Could the second boost converter/charge pump replace the need for a post-Beam circuit (1381 voltage detector + transistors), by directly powering the BBC microbit in the appropriate conditions ?
      * Could we put some MFC in series, and use a different charge pump with a higher supply/input voltage, but a higher output voltage to directly power the BBC microbit from the charge pump ?      * Could we put some MFC in series, and use a different charge pump with a higher supply/input voltage, but a higher output voltage to directly power the BBC microbit from the charge pump ?
-     * Circuit design constraints+     * Circuit design constraints :
        * Few and available (not outdated) components, big enough to be soldered with Fablab equipment.        * Few and available (not outdated) components, big enough to be soldered with Fablab equipment.
        * Available (and not outdated) components.        * Available (and not outdated) components.
  
 ==2.5.2 1-hour parallel post-chip supercap charge== ==2.5.2 1-hour parallel post-chip supercap charge==
 +
 +{{>http://www.flickr.com/photos/foam/36440356604/  ?maxwidth=400}}\\
  
    * We connected our three (inequally) working Mudwatts in parallel to a 0.22 F 2.5 V supercap.    * We connected our three (inequally) working Mudwatts in parallel to a 0.22 F 2.5 V supercap.
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