"What did the first brain to find itself on this planet do? Presumably it was astonished at being here and hadn't a clue what to make of itself and the filthy vehicle beneath its feet. In the meantime people have come to terms with their brains by regarding them as so unimportant as to be not even worth ignoring, by making rastas of themselves (bottommost: blackish pole; uppermost; the president of the senate, say) and by turning the so-unjustly beloved nature into the backdrop for a right farce. Although this doubtless not especially heroic way of avoiding a dilemma that still receives insufficient appreciation has become quite void of any charm now that it is so utterly predictable (how infantile bathroom scales are!), for this self-same reason it is, however, highly suitable for the conducting of certain procedures." - Walter Serner in Last Loosening Manifesto (1916)

"The concept of reality is a highly variable value, and entirely dependent on the brain and the requirements of the brain which considers it." - Richard Hülsenbeck in En Avant Dada (1920)

"After all, what is an art object, in any discipline,
but a beautifully woven system of life-giving lies that burst with potentiality?"
- Olchar E. Lindsann in Cheating Art History:
Strategies on the Fight Against Modernism ( ADa 91 )

"The pressure of occupation and the incessant stream of impressions pouring into our consciousness through all the gateways of knowledge make modern existence hazardous in many ways. Most persons are so absorbed in the contemplation of the outside world that they are wholly oblivious to what is passing on within themselves. The premature death of millions is primarily traceable to this cause." - Nikola Tesla in My Inventions (1919)

"I am not an artist because I refuse to be bored." - David Beris Edwards in BARM ( ADa 92 )

"Every manifestation of our life is accompanied by noise." - Luigi Russolo in L'arte dei rumori ( 1913 )

Friday, September 28, 2012

Significant Design Advancements for the CCC

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About a week ago I wrote a post titled Cycler Current Cystems where I outlined a plan to build an auxillary power system for my bike, allowing me to power an Arduino and LED light strip, an LG phone, a WiFi device, and an Acer 0751h netbook.

I've made some headway. At first, I was pretty frustrated with disjunct and lacking information I came upon, so I wrote a list of the courses I would take at a free school (Hello Star City Shadow School) if courses like these existed:

Rock and Roll and the Military-Industrial Complex
AC/DC 101
DIY/DIWO, Pedagogy, and the State
Academics, Knowledge and [Anti-]Copyright
Technology, Manufacturing and Stateless Socialism
A Survey of Capitalist Sciences
Electronic Manufacture In Detail
Technology and the 19th Century Romantics
Ethics in BioHacking

After some time I was able to find some resources which allowed me to ground myself and break down the circuits I was trying to build into smaller sections for better understanding. Most of the resources were found through Instructables (Thanks Gonzalo), the DuckDuckGo search engine, and occasionally Google search.

So what you'll find below is:

A schematic of my planned system
The various circuits which make up the system
Details on the batteries used in the circuit
Battery Concerns
Ideas for a battery jumper system
Unknowns in the Arduino/LED Light Strip setup

Websites where I've sourced all of the parts I'd need to purchase
Websites that I've used as resources for everything you see

Throughout what you will read below, I still have several questions and concerns. If you feel you have the knowledge and time, please educate me by leaving comments below. As always, I'm in a time crunch to build this, so the sooner I can resolve these questions, the better.

A schematic of my planned system

 

The basic charging circuit I'm working with was taken from Michael Schmidt's website Pilom.de:

Here is a schematic I drew of my proposed set of circuits. It could be better organized, but I hope it makes sense to you.

There is a battery charging circuit, and a battery use circuit. A DPDT switch delegates which circuit the batteries belong to.

Charge Circuit:
As I stated above, the charge circuit is based on the Low Power generation schematic on the Pilom website. A 12V 6W dynamo would provide varying AC power into a Bridge Rectifier made from four 1N5408 diodes which would output DC power. The Ampers and Voltage would be measured by an analog ammeter wired in a series and an analog voltmeter wired in parallel to it (analog is cheaper). Finally then, the power would go into a series of batteries. Based on Pilom's design, there would be 10 1.2V 2500mAh NiMH batteries in a series to charge. A SPST switch would be put in between the dynamo and rectifier so that I could “turn off” the circuit when not in use.

Batteries:
1.2V x 10 gives me 12V that could either be stepped up to 19V or down to 5V. Over 2Ah is needed since the Arduino + LED Strip can potentially draw up to 2.08mAh according to the Arduino/LED strip tutorial on the Adafruit website (see below).

Charging & Current: The idea is to “trickle charge” the batteries with a relatively constant current from the dynamo. I won't know what kind of output the dynamo will give me until I attach it to my bike and measure output at different speeds with a multimeter. Whoever contributed to this section of the Wiki article on trickle charging NiMH batteries cites a Duracell document on NiMH batteries that: “Most manufacturers claim that overcharging is safe at very low currents, below 0.1 C (where C is the current equivalent to the capacity of the battery divided by one hour).” 0.1C for these batteries would be 250mA. If it is true that the dynamo produces .5mA at a fairly consistently at some average speed, spread across 10 batteries, I would be pushing 50mA into them, well below 0.1C for a relatively “safe” charge and over-charge.

Charging & Voltage: Somewhere, but I can't find the webpage at this time, I read that if the battery pack is rated a 12V, the power source must produce slightly more voltage (~13V-14V) in order to charge them. If this is true, the 12V 6W dynamo may not produce enough voltage to charge the batteries. I only need 12V from the batteries in order to be able to step up to voltage to 19V to charge my netbook battery. I could avoid this problem by removing this capability from the Use Circuit (see Use Circuit below). At that point, I would only need 5 batteries at 6V to step-down to 5V for the Arduino and USB port. This would also mean that if the dynamo produces .5mA, 100mA would be spread across 5 batteries during charging, still below the “safe” C0.1 rate for over-charging NiMH.

I won't know how much voltage the dynamo produces until I can test it. But if someone is more experienced with this issue I'm exploring under “Charging & Voltage,” please educate me.

Jumper System: I will have 10 single AA battery holders for the 10 batteries I plan to use. They each have two tabs on them and I will wire them in a series. The Pilom website mentions that a jumper could be created so that less batteries may be used in the same circuit without having to decrease the number of battery holders, etc. How could this be done?

Concerns:
One drawback here is that I have no idea when the batteries are depleted or when they are fully charged. I need to do more research on this, but some pages that I have scanned stated there is no simple way of doing this. If anyone has more info in regard to a relatively easy way to measure this, please let me know.

Measuring charge/depletion seems to be important because of something that wppltd.demon.co.uk calls “Cell Reversal” where the cell is depleted prior to the other cells and the way the current flows is reversed. Some other website (again, I can't find it at the moment) called this “deep discharge” and stated that this could damage the rest of the circuits and/or batteries. Can someone clarify this as well?

Use Circuit:
The use circuit is divided into three sections using two DPDT switches. Once the Use Circuit is selected, the first DPDT switch decides whether the 12V from the battery pack will be stepped up to 19V for charging my Acer 0751h netbook or if it will be stepped down to 5V. The stepped down voltage (5V) can power either a female-USB port or the Arduino/LED Strip (LPD8806) selected via another DPDT switch. The LM2577 circuit found on ebay or Amazon from Hong Kong would do the stepping up/down. I was originally thinking of using a 7805 linear voltage regulator to step the voltage down to 5V for the USB/Arduino-LED setup, but realized that its max Amperage would be 1.5 at most. This would be insufficient for the potential 2A+ draw that the Arduino/LED strip would create.

Yet unplanned:
Powering the Arduino & LED Strip.
There is a bit of confusion here which I need clarified. I want to power both the Arduino and the LED strip from the same 5V source. The Adafruit tutorial says this is possible, but the way they word their instruction is unclear. “For a standalone application (not USB connected to a computer), you can power the Arduino from the same regulated 5V supply as the LEDs — connect to the 5V pin on the Arduino, not Vin, and don’t use the DC jack on the Arduino.” Is this stating I should connect the regulated 5V into the 5V pin? If so, where do I plug in the power connector that goes to the LED strip? It states that I shouldn't power the Arduino/LED strip by plugging into the Vin plug. Is this because the Vin plug requires 7-12V?

Arduino / Light Strip tutorial – Power section: [ http://learn.adafruit.com/digital-led-strip/powering ]

“5V.This pin outputs a regulated 5V from the regulator on the board. The board can be supplied with power either from the DC power jack (7 - 12V), the USB connector (5V), or the VIN pin of the board (7-12V). Supplying voltage via the 5V or 3.3V pins bypasses the regulator, and can damage your board. We don't advise it. “



Sourced Parts 

Dynamo:
6V 3W

A China-made 6V 3W:

12V 6W

Rectifier:
four 1N5408 diodes

Voltmeter/Ammeter:

Batteries:
or


Perf Board:

Jumper system: ?

Things I may already have:
3 DPDT toggle switches
1 SPST toggle switch
female-USB end & cable
2.1mm barrel adapter & cable



Online Resources

Batteries in a Series or Parallel:

Working Circuit which Charges 4 NiMH batteries. (Must contact this person.):

Myra Simon's tests of various 6V 3W dynamos and their power output:

Pilom's Dynamo tests but using a voltage doubler, which I didn't want to look into at the time:

USB 1 & 2 Voltage specifications:

More discussion on USB Voltage specs:

Watts:

On Linear Voltage Regulators:

Common Schematic Symbols:

NiMH – NiCd Charging Methods:

More on NiMH charging:

More on NiMH charging:

Duracell's Document on charging their NiMH batteries:

Similar Dynamo Bike Light & USB/Battery Charger Circuit:

Resources related to Academia, Knowledge, & Copyright:

University of Colorado Interactive Simulations:

C.R. Nave's informative but inaccessable “HyperPhysics” Learning Tool at George State University:

Pilom – M.S. Contact & Disclaimer Info:
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1 comment:

  1. tomislavOctober 1, 2012 at 8:58 AM

    One note to the above post:

    I've since gotten an Arduino. After working with it for a bit, I think hooking up the LED strip to it won't be a problem.

    ReplyDelete

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