Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision		 Previous revision
michka:research:microbial_fuel_cells:brussels7 [2017-09-20 17:00] – michkamichka:research:microbial_fuel_cells:brussels7 [2017-09-20 17:54] (current) – michka
Line 5: Line 5:
 ====Abstract==== ====Abstract====
  
-// To be updated +   * Paul prototyped and made a series of clay pots to host our MFCs. 
- +   * Paul designed the final version of the robots, and built the first one. 
-   * I connected and tested the last version of our Power Harnessing System (PHS) circuit of [[michka:research:microbial_fuel_cells:cardiff6|our last working session in Cardiff]]. +   * Paul started up the MFCs, and performed power tests. 
-   * We saw that the energy bursts provided by the one-transistor version of the PHS circuit to the BBC microbit were quite short because of a mismatch between the nominal charge voltage of the supercap (2.7 V), the minimal power supply voltage of the BBC microbit (1.7 V), and the voltage drop across the circuit (about 1 V). +   * Paul wrote our contribution to the V&A Digital Design weekend publication. 
-   * The duration of the BBC microbit activity bursts seems to increase linearily as the capacity of the supercaps increase. +   * Michka performed tests on the Power Harnessing System (PHS) circuit. 
-   * We also observed that the two-transistor version of the PHS circuit in which the second transistor is activated by the BBC microbit itself does not seem to work, and probably never will, because it seems that the output voltage provided by the BBC microbit cannot be higher than the voltage it is supplied with.+     * The best circuit we got so far is the following one : 
 +       * the + pin of the power supply is connected to the + pin of the supercapacitor. 
 +       * the + pin of the supercapacitor is connected to the + input pin of the 1381E. 
 +       * the - pin of the supercapacitor is conneced to the ground of the power supply. 
 +       * the - input pin of the 1381E is connected to the ground of the power supply. 
 +       * the output pin of the 1381E is connected to the gate of a KSD5041QTA transistor. 
 +       * the collector of the transistor is connected to the  
 +       * the emitter of the transistor is connected to the 3V pin of the BBC microbit. 
 +       * the ground pin of the BBC microbit is connected to the ground of the power supply. 
 +     * With two 2.8 V 10F supercaps in parallel, we obtain a 56 seconds run of the blinking BBC microbit.
  
 ====Paul, July 15th==== ====Paul, July 15th====
- 
-https://www.flickr.com/photos/foam/36922074150 
  
    * Paul made some clay prototyping and cooking in Claire’s oven in the summer, testing a container design for our V&A DIY microbial fuel cells.    * Paul made some clay prototyping and cooking in Claire’s oven in the summer, testing a container design for our V&A DIY microbial fuel cells.
    * He will try to make a series in Cardiff University’s ceramic workshop over the summer.    * He will try to make a series in Cardiff University’s ceramic workshop over the summer.
 +
 +{{>http://www.flickr.com/photos/foam/36922074150/  ?maxwidth=400}}\\
  
 ====Paul, July 31st==== ====Paul, July 31st====
  
-https://www.flickr.com/photos/foam/37319691335+   * Paul wrote a first version of our contribution to the V&A Digital Design Weekend documentation.
  
-   * Paul wrote a first version of our contribution to the V&A Digital Design Weekend documentation.+{{>http://www.flickr.com/photos/foam/37319691335/  ?maxwidth=400}}\\
  
 ====Michka, September 3rd==== ====Michka, September 3rd====
Line 33: Line 42:
    * Paul worked on:    * Paul worked on:
       * Making the new clay pots series for the V&A MFCs.       * Making the new clay pots series for the V&A MFCs.
-https://www.flickr.com/photos/foam/37319690795/in/dateposted/ +{{>http://www.flickr.com/photos/foam/37319690795/  ?maxwidth=400}}\\ 
-https://www.flickr.com/photos/foam/37146968352 +{{>http://www.flickr.com/photos/foam/37146968352/  ?maxwidth=400}}\\ 
-      * Testing stainless-steel-scrubbers electrodes - which at least partially worked+        * The clay pots had to cook over 36 hours, the temperature gradually rising to 1200 °C. This high temperature allows for waterproofing of the pots without the use of glaze or additional treatments. 
 +      * Testing stainless-steel-scrubbers electrodes - which at least partially worked. 
 +        * Over the long term, they seem to work as well as the test battery with graphite felt electrodes.
       * Designing & prototyping the robotic system design       * Designing & prototyping the robotic system design
-https://www.flickr.com/photos/foam/37319691035/in/dateposted/+{{>http://www.flickr.com/photos/foam/37319691035/  ?maxwidth=400}}\\
          * The current structure is made of two BBC microbit modules which communicate, placed in a clay/metal structure.          * The current structure is made of two BBC microbit modules which communicate, placed in a clay/metal structure.
  
Line 47: Line 58:
  
    * Paul made a quick prototype of the horizontally-moving part of the robot, which runs at 1.9 V.    * Paul made a quick prototype of the horizontally-moving part of the robot, which runs at 1.9 V.
-https://www.flickr.com/photos/foam/37146968152+{{>http://www.flickr.com/photos/foam/37146968152/  ?maxwidth=400}}\\
  
-====Paul, September 14th==== +====Michka, September 13th====
- +
-   * Paul filled up the 13 batteries a few days ago. +
-https://www.flickr.com/photos/foam/37146967402 +
-https://www.flickr.com/photos/foam/37319690935 +
-   * This morning : +
-      * Two of them do not work. +
-      * One has a voltage of 0.13 V. +
-      * The others have a voltage between 0.55 and 0.76 V. +
-https://www.flickr.com/photos/foam/36506067793 +
-      * When combining all in series, Paul measures 5.7 V, which allows to run the BBC microbit displaying text during 1 to 2 minutes ! +
- Video : powerOfTheMudShortEdit +
- +
-///////////////////////////////////////////////////////////////////////////////// REPRENDRE ICI +
- +
-====Paul, September 16th==== +
- +
-Ici updates: j’ai finalisé le petit robot sur rails, il est légèrement moins trash. Le conteneur en céramique pour l’autre robot est prêt, sorti du four cet après-midi.  +
-J’ai un supercap de 10F en charge sur 12 batteries, il est monté à 1.8V en 6 heures, mais ne gagne maintenant que 1mV/3mn à peu près. +
-J’ai branché le robot (moteur + led + microbit) directement sur les piles, rien ne se passe. Le robot consomme environ 100mA à 2V sur alimentation secteur. Le microbit tout seul fonctionne 1mn environ avec texte sur les leds dans la même configuration. +
-Food for thought et experimentations… +
-Bises et bon weekend à toi aussi! +
- +
-====Paul, September 18th==== +
- +
-Un petit dernier update du weekend: +
-Le supercap de 10F a atteint 2.690 V à 22h30, soit 23 heures après être mis en charge avec un voltage de départ de 0.35V aux bornes du supercap, 5.9V aux batteries. La charge a fait tourner le robot 7mn (microbit avec leds, moteur, led). +
-Le microbit s’est arrêté à 1.667V. J’ai remis le supercap en charge, je suis curieux de voir combien de temps il prend pour revenir à 2.7v. +
-Demain j’essaierai avec un 0.22F, que j’ai à l’atelier, potentiellement 12s d’actuation pour 40 fois moins de temps, ça commence à être pas mal. +
-Pour DDW je pense préparer un système manuel en plus du circuit, un simple switch qui permet de passer de charge à décharge, avec des terminaux pour brancher un voltmètre. +
-Ce matin 2.5V. +
-Bonne chance avec EDF! +
-Bises, à demain :>)) +
- +
-====Michka, September====+
  
 ===Tests with resistor-based voltage divider=== ===Tests with resistor-based voltage divider===
Line 93: Line 70:
    * However, I kept having funny results. I tested many of the components, and finally concluded with a test without the voltage divider that it might be perturbing the correct working of the circuit.    * However, I kept having funny results. I tested many of the components, and finally concluded with a test without the voltage divider that it might be perturbing the correct working of the circuit.
    * I will therefore not present here the hectic results of these first tests.    * I will therefore not present here the hectic results of these first tests.
 +
 +====Michka, September 14th====
  
 ===Tests directly powered by the power supply=== ===Tests directly powered by the power supply===
Line 167: Line 146:
      * The voltage drop between the + input pin voltage and the output voltage seems to be around -0.15 to -0.2 V.      * The voltage drop between the + input pin voltage and the output voltage seems to be around -0.15 to -0.2 V.
  
-===Discussion, conclusion, future work===+===Discussion & conclusion===
  
    * The current typology of the one-transistor version of the circuit does not give the BBC microbit a long autonomy because there is a mismatch between the nominal charge voltage of the supercap, the minimal power supply voltage of the BBC microbit, and the voltage drop across the circuit. Possible options to overcome these pitfalls include :    * The current typology of the one-transistor version of the circuit does not give the BBC microbit a long autonomy because there is a mismatch between the nominal charge voltage of the supercap, the minimal power supply voltage of the BBC microbit, and the voltage drop across the circuit. Possible options to overcome these pitfalls include :
Line 185: Line 164:
  
    * We could also try out what happens when we change the 1381E to 1381J.    * We could also try out what happens when we change the 1381E to 1381J.
 +
 +====Paul, September 14th====
 +
 +   * Paul filled up the 13 batteries a few days ago.
 +{{>http://www.flickr.com/photos/foam/37146967402/  ?maxwidth=400}}\\
 +{{>http://www.flickr.com/photos/foam/37319690935/  ?maxwidth=400}}\\
 +   * This morning :
 +      * Two of them do not work.
 +      * One has a voltage of 0.13 V.
 +      * The others have a voltage between 0.55 and 0.76 V.
 +{{>http://www.flickr.com/photos/foam/36506067793/  ?maxwidth=400}}\\
 +      * When combining all in series, Paul measures 5.7 V, which allows to run the BBC microbit displaying text during 1 to 2 minutes !
 + Video : powerOfTheMudShortEdit
 +
 +====Michka, September 15th====
  
 ==Test #10 - Changing the transistors== ==Test #10 - Changing the transistors==
  
-   * Results to be transcribed from notes. +   * I tested several transistors I had on a shelf after my unfortunate joule thief experiments. 
-   * (Spoiler : the KSD5041QTA is the best transistor I have for this regard.)+   * I replaced the 2N3904 with each of them and watched how the circuit performed. 
 +     * Regarding the SS850BBN transistor: 
 +       * The voltage at the + pin of the power supply was 2.81 V. 
 +       * The voltage at the 3V pin of the BBC microbit was 1.98 V. 
 +       * The voltage at the output pin of the 1381E was 2.69 V. 
 +       * The collector-emitter voltage drop was 0.71 V. 
 +       * When running the BBC microbit on the supercap, the BBC microbit stopped to work when the voltage across the supercap reached 2.51 V, after about 16 seconds operation. 
 +     * Regarding the BC63916 transistor: 
 +       * The voltage at the + pin of the power supply was 2.81 V. 
 +       * The voltage at the output pin of the 1381E was 2.71 V. 
 +       * The voltage at the 3V pin of the BBC microbit was 1.98 V. 
 +       * The collector-emitter voltage drop was 0.73 V. 
 +     * Regarding the KSD5041QTA transistor: 
 +       * The voltage at the + pin of the power supply was 2.81 V. 
 +       * The voltage at the output pin of the 1381E was 2.75 V. 
 +       * The voltage at the 3V pin of the BBC microbit was 2.09 V. 
 +       * The collector-emitter voltage drop was 0.66 V. 
 +       * When running the BBC microbit on the supercap, the BBC microbit stopped to work when the voltage across the supercap reached 2.41 V, after about 25 seconds operation. 
 +   * **Conclusion : the KSD5041QTA is the transistor which allows the longest run time for the BBC microbit.**
  
 ==Test #11 - Switching the 1381E for 1381J== ==Test #11 - Switching the 1381E for 1381J==
  
    * The 1381J voltage detector does not trigger at 2.8 V, probably because the voltage is too low, we therefore get a 0 voltage on the 1381J output, and a 0 voltage on the BBC microbit 3V power supply pin.    * The 1381J voltage detector does not trigger at 2.8 V, probably because the voltage is too low, we therefore get a 0 voltage on the 1381J output, and a 0 voltage on the BBC microbit 3V power supply pin.
-   * Conclusion : using the 1381J does not improve the autonomy of the BBC microbit.+   * **Conclusion : using the 1381J does not improve the autonomy of the BBC microbit.**
  
 ==Test #12 - Changing the BBC microbit output mode from analog to digital== ==Test #12 - Changing the BBC microbit output mode from analog to digital==
Line 202: Line 214:
    * When powered through our one-transistor circuit, we obtain 1,75 V on pin 1, the same as on (analog) pin 0, input power pin 3V being powered at 1,84 V.    * When powered through our one-transistor circuit, we obtain 1,75 V on pin 1, the same as on (analog) pin 0, input power pin 3V being powered at 1,84 V.
      * We therefore cannot hope that the BBC microbit will open the gate of the second transistor controlling the line powering itself, as the gate voltage will always be a little bit lower than the emitter voltage in this version of a two-transistors circuit.      * We therefore cannot hope that the BBC microbit will open the gate of the second transistor controlling the line powering itself, as the gate voltage will always be a little bit lower than the emitter voltage in this version of a two-transistors circuit.
-   * Conclusion : using the digital output of the BBC microbit does not improve the autonomy of the BBC microbit.+   * **Conclusion : using the digital output of the BBC microbit does not improve the autonomy of the BBC microbit.** 
 + 
 +====Michka, September 16th====
  
 ==Test #13 - Changing the supercapacitors== ==Test #13 - Changing the supercapacitors==
  
-   * For some with higher nominal charge voltage - Experiment still to be performed. +   * For some with higher nominal charge voltage ? 
-   * For some with higher capacity - Experiment still to be performed.+   * For some with higher capacity ?
    * Elak needed one week delivery to provide supercaps, so experiment cancelled for now...    * Elak needed one week delivery to provide supercaps, so experiment cancelled for now...
-   * But, in the shower, a light bulb sprouted on top of my head. To increase the operation voltage of the circuit or the overall capacity, I could just pile up supercapacitors !!!+   * But, in the shower, an idea occured to me: to increase the operation voltage of the circuit or the overall capacity, I could just pile up supercapacitors !!!
    
 ==Test #14 - Piling up supercapacitors in series== ==Test #14 - Piling up supercapacitors in series==
Line 237: Line 251:
    * The BBC microbit seems to light up when the voltmeter shows 2.67 V on the + pin of the power supply.    * The BBC microbit seems to light up when the voltmeter shows 2.67 V on the + pin of the power supply.
  
-==Test #17 - Test autonomy while running a motor on BBC microbit==+====Paul, September 16th====
  
-Experiment still to be performed.+   * Paul finalized the rail-based robot. 
 +   * Paul finalized the ceramic container for the second robot, which ended its oven cooking over the afternoon. 
 +   * Paul plugged a 10 F supercap on the 12 working clay MFCs. 
 +     * It charged up to 1.8 V in 6 hours. 
 +     * Afterwards, it only charged 1 mV every 3 minutes. 
 +   * When plugging directly our first robot on the batteries, nothing happens. 
 +   * When connected to the power supply, the robot consumes about 100 mA at 2 V. 
 +   * Microbit alone displays text for about one minute in the same configuration.
  
-==Test #18 - Try again the two-transistors topology with parallel two-supercaps charge==+====Paul, September 18th====
  
-Experiment still to be performed.+   * The 10 F supercap plugged on the batteries reached 2.690 V 23 hours after being put to charge. It had an initial voltage before charge of 0.35 V, when the batteries without any load where giving 5.9 V. 
 +   * This 10 F charge made the first V&A robot run for seven minutes. 
 +   * When the robot stopped, the 10 F supercap was still giving 1.667 V. 
 +   * Paul wants to try to replace the 10 F supercap for a 0.22 F supercap, which would allow 12 seconds operation for 40 times less charging time. 
 +   * Paul is also preparing : 
 +     * a manual charging system for the V&A installation for demonstration purposes 
 +     * a simple switch which will allow us to control ourself the charge/discharge pattern, with terminals for voltmeter measurement
  
-==Test #19 - Testing again the two-transistor Solarbot design==+====Possible future tests====
  
-Experiment still to be performed.+   * Test autonomy while running a motor on BBC microbit 
 +   * Try again the two-transistors topology with parallel two-supercaps charge 
 +   * Testing again the two-transistor Solarbot design
  • michka/research/microbial_fuel_cells/brussels7.1505926811.txt.gz
  • Last modified: 2017-09-20 17:00
  • by michka