# Dyna powered Amoeba clone



## pe2erwin (Jan 20, 2009)

I Hope that this is not considered sacrilegious, but I am attempting to build a Dynamo powered Amoeba clone 

I Started out with a piece of aluminium tube, 20x20x1.5mm.

These are some pictures i made of my building efforts today. The parts for the housing are complete and the wiring is connected to two supercaps. The XR-E Q5 did not quite fit, so I had to trim the star a little.









Same for both lenses, Originally bought with some other destination in mind, they did not fit the tiny aluminium tube (17x17mm). In my attempts to make them fit, I chipped them  









Here, both emitters are fed 0.5 Amps from a power supply. Now it really strikes me what small size this light is; Only 40x39x20mm :!:









The two 0.1F 5.5V supercaps feeding the LEDs. Look mom, no wires :!:









The intend of this light is to replace an incan light on one of my bicycles. It will need a bridge rectifier and tuning caps (Martins circuit #7 for two LEDs and a bottle dynamo). They will be mounted externally, so I can tweak them some. I Doubt if two additional caps, a resistor an four diodes would fit inside anyway.


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## scar (Jun 2, 2005)

Very cool :thumbsup: Keep us posted with updates.


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## znomit (Dec 27, 2007)

Nice work.
The supercaps across the main LEDs works OK but you can do much better with a single supercap charged to a higher voltage through a zener and powering a single led. 
This guy is still shinning when I'm finished coughing up my lungs after a hard ride.
Heres my implementation with ideas stolen from Martin, Ktronik, and Frontranger.


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## pe2erwin (Jan 20, 2009)

scar said:


> Very cool :thumbsup: Keep us posted with updates.


Thanks for the encouragement  I Like your design!


znomit said:


> The supercaps across the main LEDs works OK but you can do much better with a single supercap charged to a higher voltage through a zener and powering a single led.


Thank you for the advise. The supercaps are there to stop the light flickering at low speeds. The 'afterglow' is just a bonus to me. Although I must admit I was disappointed when I saw how short the afterglow effect is in this configuration. I See that you use a 1F supercap. Mine is only 0.1F (scavenged them from an old PCB)...

Let me think about reconfiguring it... Need to mount a cover for the optics and make a mount for it first... Maybe increase the 47 Ohm to 100 Ohm...









EDIT: Or like this (The supercap is probably smaller in size than a 2200uF/10V cap):


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## Itess (Feb 22, 2009)

Can someone explain what these parts are for?


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## pe2erwin (Jan 20, 2009)

Itess said:


> Can someone explain what these parts are for?


No problem.

This circuit is a variation of Martin's circuit #7.
The two 220uF polarized caps together form a 110uF non-polarized cap, used to increase the voltage delivered by the dynamo, thus increasing light output.
The 47k resistor biasses the polarized caps with DC voltage, so neither one of them experiences a negative voltage across its leads.

The two 0.1F caps in series form a smoothing capacitor to stop the LEDs flickering at low speeds. The added diodes and 47 Ohm resistor make the top CREE Q5 work as a standlight - the top 0.1F cap slowly discharges through the resistor and LED. The two diodes ensure that the top capacitor is charged to approximately 6.5V - 1.3V = 5.2V because the maximum voltage for this cap is 5.5V.

Does that clarify things for you?


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## kuksul08 (Oct 8, 2006)

Nice!! The Amoeba is a wonderful light. Not sure what came first - achesalot or amoeba but it's a very good design for beginners.


For the optics, definitely check out the LEDIL square lenses. Although... it looks like you're using the smaller tubing. I used 1" square tubing and the ledil lenses fit in very nicely.


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## Itess (Feb 22, 2009)

pe2erwin said:


> No problem.
> 
> This circuit is a variation of Martin's circuit #7.
> The two 220uF polarized caps together form a 110uF non-polarized cap, used to increase the voltage delivered by the dynamo, thus increasing light output.


That's part is not clear to me - why capacitor increases voltage?


> Does that clarify things for you?


Yes, thanks


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## pe2erwin (Jan 20, 2009)

kuksul08 said:


> For the optics, definitely check out the LEDIL square lenses. Although... it looks like you're using the smaller tubing. I used 1" square tubing and the ledil lenses fit in very nicely.


Thank you for he advice. These tubes are 3/4" (20mmx17mm). The lenses I use are cheap Dx ones (sku 01920) that are to my liking. Usually, shipping of Ledil lenses is more expensive than the total cost for 5 Dx lenses... It is just not wise to use a pair of pliers to cut them to size. Using a dremel would be more appropriate  Next time....


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## pe2erwin (Jan 20, 2009)

Itess said:


> That's part is not clear to me - why capacitor increases voltage?


That is hard for me to explain. Fortunately, here is a page that explains it all: https://www.allaboutcircuits.com/vol_3/chpt_3/8.html

Half-wave voltage doubler (a) is composed of (b) a clamper and (c) a half-wave rectifier.

...while not exactly the same, circuit #7 is 'similar'...


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## Itess (Feb 22, 2009)

pe2erwin said:


> That is hard for me to explain. Fortunately, here is a page that explains it all: https://www.allaboutcircuits.com/vol_3/chpt_3/8.html
> 
> Half-wave voltage doubler (a) is composed of (b) a clamper and (c) a half-wave rectifier.
> 
> ...while not exactly the same, circuit #7 is 'similar'...


Thanks! Clever trick!  If I understood it right


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## pe2erwin (Jan 20, 2009)

This is what I have got so far:

Think I will use velcro between the light and the base...


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## pe2erwin (Jan 20, 2009)

I Think I can fit my original circuit inside the Amoeba...
Here it is, dangling in mid air dead bug style 








With a sine generator, no magical voltage multiplying occurs. 4.2VAC becomes 4.7VDC. I Must have been wrong in my assumption that this is just a voltage doubler circuit. Maybe something magical is going on with a dynamo attached?








I Attached a dynamo to the circuit, driven wit my Bosch:








The voltage generated is no sinewave  








Maximum RPM of my Bosch is 1000. The wheel is 20mm diameter, so my maximum simulated speed is euh...
1000/min x 20mm x PI = 62831mm/min = 3769911 mm/ hour = 3.8 kph = 2.36 mph 

The voltage going to the LEDs looks someting like this:









So If I want to simulate reasonable speed of about 26kph, I need to drive the generator at around 6800RPM :eekster:

Sorry for the blurry pictures. Bosch in one hand, camera in he other...


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## znomit (Dec 27, 2007)

pe2erwin said:


> With a sine generator, no magical voltage multiplying occurs. 4.2VAC becomes 4.7VDC. I Must have been wrong in my assumption that this is just a voltage doubler circuit.


Yeah thats not a doubler circuit. See here
http://www.pilom.com/BicycleElectronics/DynamoCircuits.htm#DualMode

The input caps just tune the circuit peak. Martin has set out values to give a nice flat curve that ramps up quickly at low speed. Ktronik has been using smaller caps to give a more peaky curve. Personally one that ramps up to 40kph works well for me. See here
http://www.candlepowerforums.com/vb/showthread.php?t=202121


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## pe2erwin (Jan 20, 2009)

pe2erwin said:


> So If I want to simulate reasonable speed of about 26kph, I need to drive the generator at around 6800RPM :eekster:


As it turned out, Tim Allen (Home Improvement) was right: I needed more power. 150Watt input; 3 Watt output 








The 'Tuning caps' had a very slight effect (I Mounted a switch to short out the caps while the dynamo was supplying power), so I left them in the circuit. Noticed no warming of those caps after about a minute or so, so no need to worry if they will hold (I Used 16V caps instead of the prescribed 63V caps...).

Circuit is now installed inside the small 20x20x37mm tube that the emitters attach to.


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## pe2erwin (Jan 20, 2009)

:drumroll: It works!

Hahahahaaaa

Just mounted it in my bike (I Am only here every other week, so I have had to be patient).

No light when walking the bike (except for the 'afterglow' effect), but enough light to ride with at more decent speeds  Hope to get a photograph of the light as mounted tomorrow.


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## pe2erwin (Jan 20, 2009)

More pictures


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## Bobblehat (Dec 1, 2007)

Hi pe2er

I notice in your Alleweder thread that you mention "Which has a lot less light than its battery powered equivalent ......". 

I'm interested in this, as I'm working my way up to starting something similar, either x2 like yours or znomit's or a x3 like ktronic's, for a hub dynamo bike.

From other dynamo light threads here, I've been impressed with the amount of light that builders have said they get compared to battery driven versions ........ OK maybe not equivalent to 1000mA, but getting close to. Plus, many statements that say that 700mA gives very little less than 1000mA to the human eye. 

Are you disappointed in the output of your Amoeba clone, or do you notice a lot less light at normal speeds from the dynamo than you would when battery driven?

Have you compared your single XR-E Q5 @900mA on the Alleweder with the x2 Dynamo light?

One thing puzzles me, if you build a dynamo light with smoothing caps across and close to the LED string (not necessarily for a stand-light) as in Martin’s circuits, can you just attach a standard LED regulated driver to run the light off a battery? Do the regulators like being attached to a LED string in parallel with a cap …….. say 4700uF or more? How do you drive your dynamo light with a battery?

[email protected]


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## pe2erwin (Jan 20, 2009)

Hi Bobblehat


Bobblehat said:


> I notice in your Alleweder thread that you mention "Which has a lot less light than its battery powered equivalent ......".


As this thread is on another forum, let me add a link for the interested: Lights for Alleweder Velomobile.


Bobblehat said:


> I'm interested in this, as I'm working my way up to starting something similar, either x2 like yours or znomit's or a x3 like ktronic's, for a hub dynamo bike.


Znomit did a better job on the standlight. I Would follow his description if I were you 


Bobblehat said:


> From other dynamo light threads here, I've been impressed with the amount of light that builders have said they get compared to battery driven versions ........ OK maybe not equivalent to 1000mA, but getting close to. Plus, many statements that say that 700mA gives very little less than 1000mA to the human eye.


I Have been referring to this light when talking about the 'battery powered equivalent': Firefly helmet light

It has two XRE-Q5 LEDs and a single 900mA driver. Same optics.


Bobblehat said:


> Are you disappointed in the output of your Amoeba clone, or do you notice a lot less light at normal speeds from the dynamo than you would when battery driven?


No, I am not disapointed.I Do notice that the dynamo powered Amoeba has less light (at normal speeds) than my battery powered Firefly. It puts out more light than the incandescent light it replaced  


Bobblehat said:


> Have you compared your single XR-E Q5 @900mA on the Alleweder with the x2 Dynamo light?


Problem is, the two lights are 100km apart, so I have not compared them one-on-one. I Will try to take the helmet light with me coming weekend and see if I can compare them side by side.


Bobblehat said:


> One thing puzzles me, if you build a dynamo light with smoothing caps across and close to the LED string (not necessarily for a stand-light) as in Martin's circuits, can you just attach a standard LED regulated driver to run the light off a battery? Do the regulators like being attached to a LED string in parallel with a cap &#8230;&#8230;.. say 4700uF or more? How do you drive your dynamo light with a battery?


I Think that the driver will have an issue with the capacitor, but have never tried it. During construction of the Amoeba clone, I used a regulated/ current limited power supply to drive the LEDS with DC, so the capacitor is not a concern then.

Keep in mind, I use a cheap bottle dynamo that also feeds a LED tail light. You will get more light with your hub dynamo I'm sure 

Erwin


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## Bobblehat (Dec 1, 2007)

Thanks for the reply Pe2er.

I'd forgotten about the Firefly ... I can see you are able to make a very valid comparison between battery and dynamo because of the Leds and optics in the two near identical lights. It's good that you think that the dynamo driven version was still worthwhile, even if less lumens.

Yes, I'd be very pleased if you get the opportunity to compare your various lights .... the comparison I would be most interested in now, if possible, is between your single battery driven XR-E with your double dynamo driven XR-Es. I do realise that comparing dynamo lights with anything is not easy unless you have some sort of motorised rig for the dynamo that can get it near to normal road speed revolutions. I'd still value your subjective impressions so that I can get an idea of what to expect from a double (or triple) XR-E dynamo light.

As reference, I only have a Tesco 2xAA Cree torch (about 750mA draw from 2 fresh Eneloops) and I'm reasonable impressed with that compared to my main lights which are overdriven Smart Halogen 10W/6W twin 6V (now at 7.2V). It would not seem to take much more than the Tesco LED torch to equal the 10W overdriven bulb.

If anyone has any advice about battery regulator driving a "dynamo" LED unit that has a parallel cap, I be pleased to hear (apologies in advance for the slight OT).

Thanks [email protected]


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## pe2erwin (Jan 20, 2009)

Bobblehat said:


> Yes, I'd be very pleased if you get the opportunity to compare your various lights .... the comparison I would be most interested in now, if possible, is between your single battery driven XR-E with your double dynamo driven XR-Es. I do realise that comparing dynamo lights with anything is not easy unless you have some sort of motorised rig for the dynamo that can get it near to normal road speed revolutions. I'd still value your subjective impressions so that I can get an idea of what to expect from a double (or triple) XR-E dynamo light.


Well, the single XR-E Q5s are all kind if fixed permanently to my Alleweder. What I can do, is tape off one of the optics on the firefly, or perhaps use this light:








It is a single XR-E Q5 Dx P60 module, powered by 8 Alkaline AAs. Not the same optic, and not sure what the drive current is exactly, so that is probably not a good comparison.

Comparison will be on the bicycle while riding, because I have no equipment or tools available 'over there'.


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## hecs_ru (Feb 14, 2009)

MC-E - 2p-2s, driver, body, and capacitor in parallel to led. Circuit drive led with 700 mA at 15 km/h (4 leds x 350 mA = 430 lumen or more). Shining begins at 6-8 km/h. Stand light approximately 30 sek. (3 series cap. 3,3F/2,5V)


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## pe2erwin (Jan 20, 2009)

hecs_ru said:


> MC-E - 2p-2s, driver, body, and capacitor in parallel to led. Circuit drive led with 700 mA at 15 km/h (4 leds x 350 mA = 430 lumen or more). Shining begins at 6-8 km/h. Stand light approximately 30 sek. (3 series cap. 3,3F/2,5V)


That is a nice and compact light  And 430 Lumens, that is plenty of light (same order of magnitude as my Firefly helmet light). It is fairly uncommon to have a constant current driver in dynamo powered lights, but I suppose it is required to limit the light/ heat at higher speeds?


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## hecs_ru (Feb 14, 2009)

It is the compromise, the leds can be connected 4s with light output 800 lumen (If there will be enough of hub power), but will no light at low speed. To receive good light at low and high speed, I think, will need boost driver, I will try.


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## kadikater (Oct 26, 2008)

hecs_ru said:


> It is the compromise, the leds can be connected 4s with light output 800 lumen (If there will be enough of hub power), but will no light at low speed. To receive good light at low and high speed, I think, will need boost driver, I will try.


look at that:

4 cree xpg in series with a low- high speed control.

from 0 to 7 km/h one led
from 7 to 14km/h 2 led
and over 14 km/h all led

http://www.mtb-news.de/forum/showthread.php?t=437115&highlight=dynamolampe

excuse my very bad english

cheers karsten


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## kadikater (Oct 26, 2008)

circuit....


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## hecs_ru (Feb 14, 2009)

Fine but difficult.


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## kadikater (Oct 26, 2008)

pics....

cheers karsten


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## pe2erwin (Jan 20, 2009)

@ Bobblehat,

There are some fine examples for you for a dynamo powered light above 

Just did the test as promised. Compared the dynamo powered Amoeba Clone to the Battery Powered Firefly (which is also an Amoeba clone...). 

The Dynamo powered light @20 km/h puts out less light than a single LED of the Firefly. If I had to estimate, I would put the Dynamo powered light at 100 Lumens, one LED of the Firefly at 200 and both LEDs of the Firefly at 400 Lumens. You get the picture 

But do not be discouraged. I Am sure that a hub dynamo will give you better results. Or even a more efficient bottle type dynamo.

Erwin


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## znomit (Dec 27, 2007)

pe2erwin said:


> @ Bobblehat,
> 
> There are some fine examples for you for a dynamo powered light above
> 
> ...


Thats interesting, you should be getting more than half the light out of the dyno based on Martins data. Maybe the supercaps are messing things up?

ps, lots of cool stuff in this thread :thumbsup:


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## Bobblehat (Dec 1, 2007)

Thanks Erwin, your info gives me a good idea what to expect. I believe the Tesco 2AA 3W torch is about 100 lumens so I have a benchmark.

With your info and the two CPF threads from znomit and ktronic, I'm encouraged to have a go. I even have quite a few parts collected. I fancy a triple xpe/xpg in a Hammond 1455C802BK case which I have lying around. Might even cut it in two and do switchable high/low cases with different optics. Only thing now is where to get the xpe/xpg, and optics. Do I go for a single 20mm triple board and round triple optic or ...... 3 x 16mm boards and 3 separate optics? Decisions, decisions!

Znomit …. Could you expand on “should be getting more than half the light out of the dyno based on Martins data”? Do you mean half as much again, i.e 150 lumens (estimated)? Martin’s site is a goldmine!

Yeah! Great thread for me ….cheers [email protected]


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## znomit (Dec 27, 2007)

Bobblehat said:


> Znomit &#8230;. Could you expand on "should be getting more than half the light out of the dyno based on Martins data"? Do you mean half as much again, i.e 150 lumens (estimated)? Martin's site is a goldmine!


It should be driving the LEDs at around 500mA which is about 70% of the lumens you get at 800mA (what the DX driver in the firefly is putting out).
So the dyno light should be a bit brighter than a single LED from the firefly, and a bit dimmer than both LEDs.


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## Bobblehat (Dec 1, 2007)

Thanks znomit ...see what you mean now. That's even more encouraging!


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## pe2erwin (Jan 20, 2009)

znomit said:


> Thats interesting, you should be getting more than half the light out of the dyno based on Martins data. Maybe the supercaps are messing things up?
> 
> ps, lots of cool stuff in this thread :thumbsup:


I Tested the difference on the bench - supercaps versus a regular 2200uF capacitor and found no difference. I Also found little or no difference between the circuit with and without the series tuning capacitor. I Added a switch to short circuit the tuning cap and measure the voltage across the LED/ smoothing capacitor. I Recall the difference was very small (in the order of milli-Volts). Probably, the tuning caps are not the right value for this particular combination, but I did not investigate further and built the light with the tuning caps anyway.

Maybe it is the nice paintjob on the Firefly that explains the difference 


Incidentally, the Dx driver is now new and improved (sku 3256) and puts out 900mA instead of the 800mA mentioned on the Dx site. But that does not explain the difference in light intensity either.

I Suspect the real difference lies in the different type of dynamo used. Martin uses this one: Busch & Müller Dymotec6 bottle dynamo (8 magnetic poles) - a reputable brand. The one I use is more a "cheapy from the supermarket". Refer to Martin's page: Bicycle Dynamos


..or maybe there is a zener diode in the LED tail light - but that is not common. I'll check anyway.

EDIT: Found that the Union Quattro dynamo is also sold as a 'High Efficiency' dynamo branded as 'Basta Quattro' - maybe the dynamo is not to blame after all.


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## znomit (Dec 27, 2007)

pe2erwin said:


> ..or maybe there is a zener diode in the LED tail light - but that is not common. I'll check anyway.


Yeah 6V zener would explain it... 3V per LED, under 50lm each.


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## Bobblehat (Dec 1, 2007)

More, more! :thumbsup: Thanks folks.


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## pe2erwin (Jan 20, 2009)

Unfortunately, no easy fix for me.This is the rear light, a *Gazelle Power-LED*:








Inside, no zener. Just one diode, smoothing Capacitor and 1F supercap.








No easy access to the rear of the PCB. The wires are too short to remove it more than a few mm.
(Sorry for the blurry cellphone pics)


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## seanspotatobusiness (Apr 26, 2008)

Did you ever get to the bottom of this? Is it necessary to use the original PCB at all? Can't you bypass that and connect your wires to the LED directly? Would be awkward but you could solder the old wires loose and connect extensions too them? Or not?


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## pe2erwin (Jan 20, 2009)

seanspotatobusiness said:


> Did you ever get to the bottom of this? Is it necessary to use the original PCB at all? Can't you bypass that and connect your wires to the LED directly? Would be awkward but you could solder the old wires loose and connect extensions too them? Or not?


No, I did not. Just use it as-is


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