# DX P7 Bike light MEGA MODE



## jetigm (Apr 14, 2009)

Hi all  First of all sorry for my English, hope it good enough to understand what I done  
Her is my *HA-III SSC P7-C (SXO) 3-Mode 900-Lumen LED Bike Light Set* mod. The project is free, so any who have proper skills can do this improvement.
After several times of using this pretty cheap bike light, I find bad usability of this product. The flashing mode is useless, we have no "low" mode and the cycling mode selection with turning off as for me is not very comfortably. So I decide to build my own "computer" which realize each of my desired mode 

Ho to use:
Fast click to turn on the first mode.
3 mode's are available:
1. "low"
2. "mid"
3. "high"
Mode's selection is cycling by fast click (< 0.5 second): 
-> low -> mid -> high -> 
|__________________| 
Holding switch more than 0.5 seconds in any mode turns off the P7.
When the batt go to discharge level, the red led is on and mode go to previous if it was "mid" or "high".

Also I rise a current up to 2.5A at P7 by means of current-limiting resistors on driver circuit. At my point those two resistors are not very powerful to work proper at such high current that we have and they are burned out just in time of testing when I switch on and off the P7. So those many 1Ohm resistors which you see on photo is not just to rise the current but also to provide a reliability.

Some photo:


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## jetigm (Apr 14, 2009)

The schematic: .spl (sPlan 6.0)
The PCB: .lay (Sprint-Layout 5.0)
The project: CodeVisionAVR Pro 2.03.9


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## odtexas (Oct 2, 2008)

Wow.........Just wow................. 
That is really an incredible job you did there.......
Thanks for sharing and raising the bar here on light design.


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## HEY HEY ITS HENDO (Feb 23, 2008)

Hi jetigm .... Great stuff :thumbsup: 
your English is excellent


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## El34 (Jan 11, 2009)

Cool stuff.

I don't recognize any of those file formats in the zip folders?


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## yetibetty (Dec 24, 2007)

Great stuff but far too much like rocket science for me.

One thing though.. you mention that you didn't like having to cycle through the modes to turn off.

You can hold the button in for around 2 seconds to turn off and the light will come back on in the same mode next time you switch on.


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## Mick01 (May 13, 2007)

yetibetty said:


> You can hold the button in for around 2 seconds to turn off and the light will come back on in the same mode next time you switch on.


This doesn't seem to work on mine. The light switches off after the 2 seconds but when I switch on again it's in high mode. Not that that's a huge issue as I generally only use it in high mode anyway. The thing that does annoy me is that when you plug the light in it switches on. Only workaround I've found is to touch the contacts briefly (light switches on for a sec) before plugging in fully.

Mick


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## Whitedog1 (Feb 3, 2009)

Excellent!! great mod!!

unfortunately way too much for my skills :madman:


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## jetigm (Apr 14, 2009)

El34 said:


> Cool stuff.
> 
> I don't recognize any of those file formats in the zip folders?


Well, schematic and PCB you can see in .jpeg, the PCB is simple so you can draw it in you favorite format, and here is just .hex files of firmware and some explanation how it works, that if you don't have CVAVR. Actually I don't know, maybe ATMEL for you is an exotic . Flashing ATTINY13 is no problem i think - I use simplest AVR ISP programmer (5 wires from LPT port).


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## Lowy (Oct 25, 2009)

Der Umbau gefällt mir.
Aber wieso verwendest du 0,079Ohm für den Strombegrenzugswiderstand und nicht etwas weniger, damit du auf 2,8 A kommst (0,0714 Ohm)?

Why did you use 0.079 Ohm resitor for current limiting?
I thing it is better to use a liitle bit smaller resistor like 14 times 1 Ohm.
(0.07 Ohm + wireresistor and transferresistors)
Then it is possible to have a forward current of 2.8 Ampere.


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## jetigm (Apr 14, 2009)

I don’t want to set the 2.8A current cause I think it is too much, the light became very hot, I don’t want any overheating so I stops at 2.5A.


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## drsquirrel (Nov 6, 2009)

Want to make a few for some others?

PIC programming and soldering etc are all within my skill set, but PCB building and sourcing various _individual_ parts can be a pain/costly.

Seeing as you have mode memory, I don't see why you couldn't keep the strobe (or change it to flash), since that would be nice for day time cycling (for roadies).


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## jetigm (Apr 14, 2009)

> Want to make a few for some others?


I don't think so, because we live tooo far from each other 



> strobe


I just don't need it.


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## essenmeinstuff (Sep 4, 2007)

Hi cool mod!

So if I understand this right, you removed some parts on the original controller, built a daughter board with the tiny13 and vcc supply on it on it and then control the driver via PWM from this?

Rather than using a lot of 1E resistors you can achieve the same with a single smt (maybe 2512?) resistor, they are available in a bunch of low ohmic values.


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## jetigm (Apr 14, 2009)

Hi essenmeinstuff.


> So if I understand this right


Absolutely right.


> 2512?


I have no 2512 size so I put the 1206 size.


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## unikum (Dec 21, 2009)

Absolutely awesome!!!! Can 't wait to try it. Thanks for sharing.


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## trottel100 (Nov 19, 2009)

can someone build one? i would buy it. Add shippment to germany.

Thanks


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## anius (Feb 16, 2010)

If I good understand, if I only change resistors (will make less Ohm) I will have more mA on output? After upgrade (2.4A -> 2.5A) I will have +~30lm? It feel in real life? How about battery life? Light will burn less time after upgrade, interesting how much less, maybe anybody tested it?


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## jetigm (Apr 14, 2009)

> less Ohm


Yes, it will increase the current. 


> After upgrade (2.4A -> 2.5A) I will have +~30lm? It feel in real life?


Not much.


> How about battery life?


Approx the same time, maybe just a little less, but not much.

You should upgrade the resistors primary to get reliable work, increasing current is a game that give you almost nothing.


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## anius (Feb 16, 2010)

I have 5 modes P7 light. Can I replace R03 and R04 and put 13 resistors 1Ohm? I will increase output mA?


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## MtbMacgyver (Jan 23, 2007)

anius said:


> I have 5 modes P7 light. Can I replace R03 and R04 and put 13 resistors 1Ohm? I will increase output mA?


The bottom of this post gives details on increasing the current by changing the current sense resistors.

http://forums.mtbr.com/showthread.php?p=6601201#post6601201


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## anius (Feb 16, 2010)

I replace resistors, to 13 resistors 1Ohm, before I have 2.4A output and now 2.7A. I don't want increase so much, but I will test it... I'm thinking about to hight temperature protection, maby someone know simple way, how to make it? If temperature to hight, I think light must go to mid mode.


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## kaos42 (Feb 24, 2010)

so how to change to 2.7A ?

what is the the part number?


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## a1rports (May 17, 2009)

You cant leave me in suspense, its like the last page is missing from a murder/mystery


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## jetigm (Apr 14, 2009)

kaos42 said:


> so how to change to 2.7A ?
> what is the the part number?


You are boys look like you first time in the forum  Reed and watch photos the 1-st post.


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## MK_ (Nov 15, 2004)

This is great. OP, commendable effort for a DIY and huge thanks for sharing.
Question, why did you opt to go with a LM317? That's a very inefficient way of regulating the voltage; why not a switching regulator?

_MK


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## jetigm (Apr 14, 2009)

> Question, why did you opt to go with a LM317? That's a very inefficient way of regulating the voltage; why not a switching regulator?


Yes, the switching regulator is more effective but I don't need it in case of feeding the controller, the consumption of ATTINY13 is much, much less then a P7 , so that is ok to go with LM317 and it cheap, and requires just a few resistors to set the voltage and a few capacitors. In case of feeding the highcurrent loads such as P7 - absolutely yes, only switching regulator give us the big efficient and low temperature.


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