On and flashing- Mtbr.com
Results 1 to 47 of 47

Thread: On and flashing

  1. #1
    mtbr member
    Reputation: uncle_bob's Avatar
    Join Date
    Jul 2010
    Posts
    65

    On and flashing

    Does anyone know of a constant current driver that is just either on or flashing. Oh and of cause cheap

  2. #2
    mtbr member
    Reputation:
    Join Date
    Jan 2011
    Posts
    22
    Boost or buck?

    For buck I've been pretty happy with sku 3256 from dealextreme (can't post links yet as < 10 posts )

    Less than $2 each and it's super easy to change the current sense resistor for different amp output. Highest I've gone is 1400ma, probably wouldn't push it much past that. Stock they've been coming in at around 900 for me.

  3. #3
    mtbr member
    Reputation: uncle_bob's Avatar
    Join Date
    Jul 2010
    Posts
    65
    Thanks for that I'll check those out

  4. #4
    mtbr member
    Reputation: Central Scrutinizer's Avatar
    Join Date
    Aug 2005
    Posts
    194
    I've also had good luck with the 3256. However, if I understand the OP's question correctly, they're looking for a 2-mode driver (on and flashing); the 3256 doesn't have a flash mode (at least mine don't).

    However, I added a cheap flashing circuit based on this diagram:



    I substituted the + and - of the 3256's input for the power LED in the diagram, and omitted the current limiting resistor. The BC337 can only handle 800ma continuous, so instead I used a TIP31AG [1] which can handle higher current.

    Then included a switch to shunt the - of the driver to ground for continuous on.

    I've only tested this on the bench so can't comment on long-term reliability. I'm somewhat concerned about whether constantly switching the driver on and off in blink mode is hard on the driver, but as schnottus mentioned, they're only $2.

    [1] https://www.mouser.com/search/Produc...CgH1ehng%3D%3D

  5. #5
    mtbr member
    Reputation:
    Join Date
    Jan 2011
    Posts
    22
    Ahh, I read it as either a driver that is on or a driver that flashes. Your interpretation makes more sense.

    I've used a 555 IC with an mosfet transistor to flash that DX driver on my taillight, it's got about 30 hours of use so far and no issues. A little bigger and more complex than scrutinizers circuit but blink time is extremely adjustable (led on time is adjusted independent of off time). If theres any interest I can scan in my drawing and post it. Nice thing is the flasher can handle something like 30 amps.

  6. #6
    mtbr member
    Reputation: uncle_bob's Avatar
    Join Date
    Jul 2010
    Posts
    65
    Sorry for the confusion, CS is right and both of these approaches seem great for what I am doing. How much room will I need for either of these two circuits.

    schnottus, not being how do you go about changing the on off timing with the 555. I have more experience shaping than soldering

  7. #7
    mtbr member
    Reputation:
    Join Date
    Jan 2011
    Posts
    22
    My scanner isn't working so I'll just try to explain it. I used the extended duty astable (section 4) from this site http://www.doctronics.co.uk/555.htm#astable.

    I wasn't sure what I thought would look good so I ended up putting variable trim resistors in place of r1 and r2 and then adjusting until I got what I wanted. I then removed the trim resistors and placed regular ones in with the value i liked.

    According to my notes I used:
    R1 = 5.88k ohm
    R2 = 15k ohm
    C1 = .1 uF
    C2 = 33 uF

    Size kind of depends on how resourceful you are and how much effort you put into it. You could use smd parts on a pcb and fit the whole 555 circuit on the surface of a dime. Since I'm guessing you are going to use through-hole components if you make this then I'd say plan on having it around the size of a quarter (maybe a little larger) if you aren't great at making compact circuits.

  8. #8
    mtbr member
    Reputation:
    Join Date
    Jan 2011
    Posts
    270
    Have you thought about using an LED flasher IC? You can get the M34 in 1Hz or 2Hz flavours with 1/8 duty cycle, it's very small and cheap (TO92 package) and doesn't need any other external components. It'll only drive 25mA I believe so you would need a transistor or the buck converter linked to earlier to drive the LED itself, but might be a neat solution. Links here and to the data sheet here.

  9. #9
    mtbr member
    Reputation: mattthemuppet's Avatar
    Join Date
    Jul 2004
    Posts
    2,374
    right, 3rd time lucky.

    Sorry for the thread hijack uncle bob, this has got me thinking. So, to turn a cheap linear converter driver (I have a KD 350mA one) into a flasher, I need to either:

    1) driver and 555 chip in series (555 on ground side) with the LED (SSC P4 probably) in parallel with some other bits'n'bobs scattered around or

    2) use one of those handy flasher IC things, with the driver and LED (in series) connected to the Vdd and LED pins

    I'm an electrical idiot so please speak slowly and loudly
    Last edited by mattthemuppet; 07-26-2011 at 06:36 AM. Reason: 3rd attempt at posting grrr

  10. #10
    mtbr member
    Reputation:
    Join Date
    Jan 2011
    Posts
    22
    Neither a 555 nor the handy flasher ic will have sufficient amp output to drive a power led, both would require a transistor set up as a switch (or possibly two in a darlington pair) on their output side. Not sure what your KD driver is but if it has an enable pin the 555 or the flasher should have no problem without the transistor.

  11. #11
    mtbr member
    Reputation:
    Join Date
    Jan 2011
    Posts
    22
    Actually that DX driver I posted is based on an ax2002 chip which after some datasheet reading I see has an enable pin... guess I made my design slightly larger and more complicated than it had to be with the transistor . Time for version 2.

  12. #12
    mtbr member
    Reputation: uncle_bob's Avatar
    Join Date
    Jul 2010
    Posts
    65
    Quote Originally Posted by mattthemuppet View Post
    right, 3rd time lucky.

    Sorry for the thread hijack uncle bob, this has got me thinking. So, to turn a cheap linear converter driver (I have a KD 350mA one) into a flasher, I need to either:

    1) driver and 555 chip in series (555 on ground side) with the LED (SSC P4 probably) in parallel with some other bits'n'bobs scattered around or

    2) use one of those handy flasher IC things, with the driver and LED (in series) connected to the Vdd and LED pins

    I'm an electrical idiot so please speak slowly and loudly
    Hijacking not a problem, the more heads we have on this the more I might? understand
    I am as must an E I as you are.

  13. #13
    mtbr member
    Reputation: uncle_bob's Avatar
    Join Date
    Jul 2010
    Posts
    65
    Quote Originally Posted by schnottus View Post
    Actually that DX driver I posted is based on an ax2002 chip which after some datasheet reading I see has an enable pin... guess I made my design slightly larger and more complicated than it had to be with the transistor . Time for version 2.
    Can you post the results of your v2 please
    Matt and I may need step by step and easily understandable schematic

  14. #14
    mtbr member
    Reputation: mattthemuppet's Avatar
    Join Date
    Jul 2004
    Posts
    2,374
    Quote Originally Posted by schnottus View Post
    Neither a 555 nor the handy flasher ic will have sufficient amp output to drive a power led, both would require a transistor set up as a switch (or possibly two in a darlington pair) on their output side. Not sure what your KD driver is but if it has an enable pin the 555 or the flasher should have no problem without the transistor.
    it's this one
    http://www.kaidomain.com/ProductDeta...ProductId=9607

    about as simple as it can get. So if my slow brain is thinking right, the driver is used to control LED current (and convert Vin to Vf) and the 555/flasher IC is used to switch the driver on and off? How does it do that in parallel (or like a momentary switch that doesn't carry much current)? Sorry for the tortuous mental process, it's been about 15 years since I had to use this part of my brain

  15. #15
    mtbr member
    Reputation:
    Join Date
    Jan 2011
    Posts
    270
    Quote Originally Posted by mattthemuppet View Post
    So if my slow brain is thinking right, the driver is used to control LED current (and convert Vin to Vf) and the 555/flasher IC is used to switch the driver on and off? How does it do that in parallel (or like a momentary switch that doesn't carry much current)? Sorry for the tortuous mental process, it's been about 15 years since I had to use this part of my brain
    Nothing wrong with your brain! Yes, the driver would control LED current and yes, the 555 / flasher IC / small flashing LED is effectively used to switch the driver on and off. The 555 and flasher IC wouldn't (and can't) handle much current themselves but can switch other integrated circuits on and off via their enable or control pins. The board you link to uses the AMC7135 current limiting IC and a 555 or flasher IC would turn this on and off just fine, via the Vdd pin which doesn't draw much current at all.

    You'd just need to be careful about logic HI and LO levels, i.e. which is on and which is off. The Vdd pin of the 7135 has to be held logic HI (i.e. battery voltage, anywhere between 2.7 - 6V) rather than logic LO (0V) for the 7135 to be on and flowing current. So therefore you'd need to make sure the 555 circuit or flasher IC provides a HI output whenever you want the current to be flowing and the LED lit. That might require the odd other component to make sure it's working the right way around.

    Quote Originally Posted by schnottus View Post
    Actually that DX driver I posted is based on an ax2002 chip which after some datasheet reading I see has an enable pin... guess I made my design slightly larger and more complicated than it had to be with the transistor . Time for version 2.
    Good spot. Does the enable pin need to be held HI or LO do you know? I'm guessing HI?

  16. #16
    mtbr member
    Reputation: mattthemuppet's Avatar
    Join Date
    Jul 2004
    Posts
    2,374
    thanks

    right, I'm getting there slowly. So, the flasher IC has a Vdd (+ve), LED - and Vss (-ve). The AMC7135 has (L>R); LED+ve, Grnd and Vdd pins. Ignoring for now the Logic stuff mentioned ^, I'm presuming that the flasher IC switches the current (and, normally the LED) between Vdd and LED on and off, so if that's to be used as the signal current to turn the AMC7135 on and off, I'm guessing that the Vdd pin of the flasher IC is connected to Vdd pin of the AMC chip (power for both) and the LED pin of the flasher IC connected to the Grnd of the AMC chip?

    something like:

  17. #17
    mtbr member
    Reputation:
    Join Date
    Jan 2011
    Posts
    22
    My scanner wasn't working so I just took a picture of the original (version 1) 555 sketch.


    Obviously you will want to play around with capacitor and resistor values to get the 555 to blink at the rate you want.

    If you do plan to use a mosfet to switch on and off don't go with the irfz44n unless you are running at least 12v to your driver, I only used it because it was one that I already had around. It needs around 12v to saturate (turn fully on) if I remember correctly. There is a logic level version with an "l" in the name (irlz44n?, not sure) that only needs around 6 volts to turn on.
    The nice thing with the transistor is you could hook it up to any driver that doesn't mind being cycled on and off since that mosfet can handle like 40 amps or so.

    I didn't make a new one for V2 however the right half with the transistor would simply be eliminated. Then send the output of the 555 (or flasher ic) to the ax2002 enable pin (I looked - it is active high). Depending on what voltage you have coming out of your 555 you may need to do some voltage regulation so as not to damage the ax2002. Remember that the driver is already sending power to the enable pin all the time since it is a constant on driver so the original trace going to that pin would need to be cut.


    mfj197 - Those flasher ic's are pretty neat, thanks for the link!

    Matthemuppet - I am not an electrical engineer but at best it looks like the led in your drawing would always be on, at worst you would fry an M34. Where normally that flasher would turn off an led (or driver) by limiting its connection to ground, your diagram has the driver already with a straight path to ground. Since the driver has a straight path to vdd and a straight path to vss, and since electricity takes the path of least resistance I think that driver would ignore the M34 and always be on.

    I would cut that lower left line and add a transistor switch between LED and GND. Look up mosfet switches, there is a lot online about wiring one up.

  18. #18
    mtbr member
    Reputation:
    Join Date
    Jan 2011
    Posts
    270
    mattthemuppet, unfortunately as schnottus says you'd probably fry the M34 and I don't think the LED would be lit at all. The AMC7135 has 3 pins, Vdd, GND and OUT. GND is connected to the battery negative as you have it, but OUT is in fact connected to the LED negative (with the LED positive connected to the battery positive). OUT is a sink for the current, not a source.

    Finally Vdd is used as the switching input - it is this pin that should be held HI or LO. The datasheet tends not to show it being used in this fashion but the myriad of 7135 drivers use pulse width modulation on this pin to dim or flash the output. We're actually not using it as a positive power supply rail (which is what Vdd normally stands for) but as a control input.

    So to the M34 (which I hasten to say I've never actually used but it looks useful). Vdd would (confusingly) be tied to the battery positive and Vss tied to the battery negative. However the output is the same sort of thing as on the 7135 - it is normally connected to the LED negative and acts as a current sink so it can't just be connected as a source to something else. I think you'd need a resistor up to the battery positive before connecting it to the Vdd pin of the 7135 (which we're using as the control input), so when the M34 is off (preventing current flow) the output pin is pulled up to logic HI by the resistor and turns on the 7135, and when the M34 is on (allowing current flow) it pulls the output pin to GND and turns off the 7135. The only problem with this is that when the M34 is on the 7135 is off, and vice versa. The M34 is designed to give short flashes of ON and longer pauses of OFF (1/8 duty cycle), so having it the other way round would mean the LED is on almost all the time but flashes off briefly - not the best!

    schnottus, any neat ways of reversing that? Sorry I can't draw any diagrams or think further at the moment - work is just about to start!

  19. #19
    mtbr member
    Reputation: manokaiser's Avatar
    Join Date
    Jun 2008
    Posts
    163

    Simple Blinky

    On this Post I have presented my current rear light that can be configured to be On, just Blinking or both On&Blinking. Very simple with minimal parts, drives a Power Led easily! See the schematic, it's not rocket science!
    Attached Thumbnails Attached Thumbnails On and flashing-rear-light.png  

    Last edited by manokaiser; 07-28-2011 at 06:59 AM. Reason: Add picture

  20. #20
    mtbr member
    Reputation: mattthemuppet's Avatar
    Join Date
    Jul 2004
    Posts
    2,374
    hmm, that looks like something I might just understand. Plus if I could wire 2 blinkys in parallel (adjusting the resistor to maintain the same current through each), then I could have them angle to the side for more visibility. So, if the power LED is connected as normal to the driver (LED +ve to battery +ve, as above) you get dim>bright blink, but how would you wire it to get off>bright blink? I remember you saying the power LED would have to be between the driver and the ground, but I can visualise how to wire that up (GRND pin > LED +ve and LED -ve to battery -ve?). It might not be rocket science but it's still bloody hard for me to understand.

    thanks everyone for all the advice, this is a very steep learning curve and way outside my comfort zone

  21. #21
    mtbr member
    Reputation:
    Join Date
    Jan 2011
    Posts
    270
    manokaiser, you say you managed to get this working so it is dim > bright blink? I'm impressed you managed that, as the 7135 isn't supposed to do that! It is designed to pass 350mA - nothing more and nothing less - when the Vdd pin is held logic HI, and also happens to pass 0mA when the Vdd pin is held logic LO. I guess it must be something to do with the fact that the switching voltage (i.e. connection from the blinky) is neither true HI or LO, but somewhere near the switching threshold of the 7135? Incidentally it's a useful mode of operation and I'm surprised more drivers don't provide dim > bright blink. I'm looking for one myself, except I need it to switch 6A or so for an SST90 ...

    mattthemuppet, the power LED can never be between the output of the 7135 and ground as the output of the 7135 is designed to sink current (current flows from battery +ve through LED into the 7135) rather that source current (current flowing out of the 7135).

  22. #22
    mtbr member
    Reputation: manokaiser's Avatar
    Join Date
    Jun 2008
    Posts
    163
    mfj197,
    You are correct about the function of 7135, should be either On or Off according to datasheet. It's not supposed to provide any other regulation so I was surprised too when I found out that functionality by luck.
    (Mattthemuppet here's your answer):
    My first try was with blinky and resistor reversed, resistor on top, blinky to the ground. That had an blinking On-Off function. Resistor is there to limit current to the blinky. Looks like it also works as a voltage divider to the driver input Vdd pin, triggering a limited On condition for the chip (Dimer brightness), then blinky switches On providing full On, brighter state momentarily and circles again...
    That's my (also limited) understanding, wish someone could clear this better.
    If someone only needs an On position, all it takes is to connect Vdd to Vsourse+ directly and drop blinky and resistor out of the circuit.
    Last edited by manokaiser; 07-28-2011 at 12:51 PM.

  23. #23
    mtbr member
    Reputation: mattthemuppet's Avatar
    Join Date
    Jul 2004
    Posts
    2,374
    so, it's taken some time for me to start putting this light together and the whole blinky thing has been an abject failure.

    If I solder the blinky LED + to B+ and LED- to B-, blinky flashes. Same if I solder blinky LED+ to Vdd pin on one of the 2 7135 chips on the board and LED- to B-. So the blinky LED works, at least. Blinky LED is 3.6Vf, 30mA - going by the above calculations, I should be using a 3Ohm resistor between Vdd and ground.

    If I solder blinky LED+ to B+ and LED- to Vdd, blinky doesn't flash and main LED is on. If I add a 15Ohm or 3Ohm resistor from blinky LED-/Vdd to B-, blinky doesn't flash and main LED is on. If I go below 3Ohm (tried 1.5 and 1), blinky doesn't flash and the main LED is off (flashes briefly when switch contact is made). None of the combinations make the main LED do anything other than be on or off.

    Any idea what's going on? I'd really like this to work as it would make a perfect all in one commuter rear light, but I've already reached the limits of my knowledge!

  24. #24
    mtbr member
    Reputation: manokaiser's Avatar
    Join Date
    Jun 2008
    Posts
    163
    Quote Originally Posted by mattthemuppet View Post
    so, it's taken some time for me to start putting this light together and the whole blinky thing has been an abject failure.

    Any idea what's going on? I'd really like this to work as it would make a perfect all in one commuter rear light, but I've already reached the limits of my knowledge!
    I know what's going on, sorry my mistake!
    There is an error on the schematic.
    R1 should be positioned between LED and Vdd, disconected from ground. Should be in series with the blinky feeding the input of the chip. I use 150 Ω but can be lower or removed. It effects the brightness of the low stage.
    I should post the correct circuit.
    Try that and it should be fine!

  25. #25
    mtbr member
    Reputation: mattthemuppet's Avatar
    Join Date
    Jul 2004
    Posts
    2,374
    no worries! Makes more sense - the resistor is working then to reduce the current through the blinky, right? Is the R1 value calculated somehow or determined empirically? I'm asking as I tried the blinky connected alone between + and Vdd and it didn't flash or effect the main LED. I have a couple of old circuit boards I scavenge resistors from, so I should have a few different values to try.

  26. #26
    mtbr member
    Reputation: manokaiser's Avatar
    Join Date
    Jun 2008
    Posts
    163
    The value of R1 is calculated to limit current to the blinky when the battery is fully charged. If you use a lower voltage source it can be removed. Try to reverce the polarity of the blinky to see what happens.
    I have to open my light to check everything, I'll probably do it later so I'll get back.

  27. #27
    mtbr member
    Reputation: mattthemuppet's Avatar
    Join Date
    Jul 2004
    Posts
    2,374
    I think I tried reversing the blinky (I have 15 or so of them!) between B+ and Vdd and it didn't work.

    I'll dig out a range of resistors and try them one by one. The blinky Vf value (3.6V according to the eBay seller) seems a bit high, hopefully that's not what's causing the problem.

    I really appreciate the help though, this will be such a sweet light if I can get this right!

  28. #28
    mtbr member
    Reputation: manokaiser's Avatar
    Join Date
    Jun 2008
    Posts
    163
    OK here is the deal!
    I have opened my light and I am reconstructing it. Pictures will follow.
    To help you with your build I will explain the new approach.

    The driver is where everything happens,and it's quite simple!
    It has 3x7135 chips with the output parraleled for all 3 of them. The input though is through the 2 diodes D1 and D2. D1 connects 1 chip and D2 connects the other 2.
    So if we replace D2 with a blinky we get 1 chip driving the LED constantly (350mA through D1) and 2 chips (through D2-blinky 700mA) added to that as high intensity flash.

    It works fine just like that with minimum effort and parts.
    The resistor on the original circuit could stay as is, or moved in series with blinky or even removed completely. It all depends on the blinky you use, it's Vf and the Battery you choose, acting as a current limiter.

    I hope things are clear now, if you have any questions I'll be happy to answer.
    I will post a video with it's function as soon as I put it back together.
    Attached Thumbnails Attached Thumbnails On and flashing-1629.jpg  

    On and flashing-driver.png  


  29. #29
    mtbr member
    Reputation: manokaiser's Avatar
    Join Date
    Jun 2008
    Posts
    163
    TIP1
    Idea for a brake light function!
    If we take a pair of cables from the blinky legs and short them through a brake switch we will have brake light functionality on top of everything!

    TIP2
    If we place the blinky in D1 position we will have 700mA constant + 350mA Flashing on top of it.

    TIP3
    If you use longer than 10 cm cable from battery to LED and back it's adviced to use a 10μF capacitor parallel to the input. Just solder it between the center (+) and the outer ring (- ) contacts, on the back side of the driver,

  30. #30
    mtbr member
    Reputation: manokaiser's Avatar
    Join Date
    Jun 2008
    Posts
    163
    I've just finished the rebuilding and testing of the new rear light. There are different kind of blinkies that would effect the first circuit depending on their Vf. For simplicity I ended up with just one 3,5 V blinky, replacing one of the drivers diodes, as in the picture above, plus an input capacitor. The optic is 120 degrees difuser. Resistors are not needed at all as the blinky can tolerate it easily. So it's as simple as it can get.
    The result is BRIGHT!!!
    I used simple a metalic bottle cup to enclose everything inside. Unfortunately my camera is broken and the mobile can't focus very close to take some clear pictures but it's as simple as it can get for everyone to build it.

  31. #31
    mtbr member
    Reputation:
    Join Date
    Nov 2011
    Posts
    27
    hi guys, I don;t have anything to add to the discussion but at ask that you keep posting. I am also starting a new dual led light set-up. One will be a flasher, fast and slow flash and one will be high / low beam. I made one previously using a Luxdrive Buck puck driver with CTL & Ref pins to control output. I then made a 555 flasher circuit with two sets of speed controlling resistors/capacitors and a dpdt switch to choose which flashing speed. For the H/L light, I used dpdt switch with one resistor for L, the other switch position was full power high. This works great, the only issue was cost of the driver. I'm looking closely at the Kaidomain drivers but and wondering how robust and reliable they are. I believe you are definately on the right track working off the Vdd pin. Please keep posting your progress. Any recommendations for a Kaidomain driver for XPG's I want to run about 1000ma on high (wire in a flashing circuit and another on a H/M/L curcuit) probably 6v 6000mAh battery

    Thanks

  32. #32
    mtbr member
    Reputation:
    Join Date
    Nov 2011
    Posts
    27
    mano - Awesome!! nice work

  33. #33
    mtbr member
    Reputation: manokaiser's Avatar
    Join Date
    Jun 2008
    Posts
    163
    Thanx Alinvanc,
    I'll be happy to see reproductions.
    Here is a working Video of it!

    Below is the next project at early stage, a blue light with the same function, request from a friend
    Attached Thumbnails Attached Thumbnails On and flashing-1625.jpg  


  34. #34
    mtbr member
    Reputation:
    Join Date
    Nov 2011
    Posts
    27

    Driver ?

    mano, are you using the S003256 driver (Li-ion 1050mAh 7135 LED Regulated circuit (3 modes)) from Kaidomain ?

    I can't believe how simple that is. I suppose if you play around with different blinkies, you can find different blinking rates.

  35. #35
    mtbr member
    Reputation:
    Join Date
    Nov 2011
    Posts
    27
    Mano, can you show pictures of your driver to show how you soldered the blinkie ?
    Also, what are the spec's of your battery & LED ?

    thanks

  36. #36
    mtbr member
    Reputation: manokaiser's Avatar
    Join Date
    Jun 2008
    Posts
    163
    I am using AMC7135 1050mA single mode driver from DX. I had a 10 pack of them, some still laying around.
    There's a new board version that might be a bit tricky as it uses only one diode. That would need a little bit of hacking, cutting the trace of one chip and shorting it to the positive suply.
    KD might still have the old version with 2 diodes.
    The Led can be THIS or any other Power led, any color, as long as it can handle the current. Note that the constant current is only 350mA , with short higher current bursts which make things easier for the Led to handle.
    Indeed different blinkies give different pulses, so pick one you like! The one I use now is a red color-red light blinky. I had a clear color - red light blinky before which I liked better but I burned by mistake.
    I have sealed the light and my mobile can't take clear close pictures so sorry no pics other than the one below, it shows the rear side with the battery connection. Still it's pretty simple to remove the diode and put the blinky on the it's traces. Blinkies have one short pin with a flat side on the led which is - and one longer pin which is +. You solder Led+ on the center hole of the board, same as Battery +. The later is a single Lion 18650 cell, perfect for the task!
    The orange cable you see in the picture goes to the Blinky - (=Vdd of 2 chips, actually bypassing the blinky through a brake switch) trace on the other side, it would be a brake signal when shorted to Battery+ feeding 750 mA constant to the Led when the power is off or full 1A when it's on, as long the main power swithc goes in series with the Battery+ line.
    Last edited by manokaiser; 02-06-2012 at 09:01 AM.

  37. #37
    mtbr member
    Reputation: manokaiser's Avatar
    Join Date
    Jun 2008
    Posts
    163
    Oh! here are the pics
    Attached Thumbnails Attached Thumbnails On and flashing-1633.jpg  

    On and flashing-1631.jpg  


  38. #38
    mtbr member
    Reputation:
    Join Date
    Nov 2011
    Posts
    27
    Mano - Shouldn't you add a diode in the short blinky circuit ?

    How did you construct your housing ?

    Thanks

  39. #39
    mtbr member
    Reputation: manokaiser's Avatar
    Join Date
    Jun 2008
    Posts
    163
    The housing is a metal cup from a parfume bottle
    The blinky IS a diode by itself. Anyway the diode is only there to prevent reversed polarity, it could be replaced by a short if you make sure you don't reverse the polarity. In the case of the brake switch thats what actually happens. As long as your battery is properly connected it's all fine!

  40. #40
    mtbr member
    Reputation: mattthemuppet's Avatar
    Join Date
    Jul 2004
    Posts
    2,374
    ah, I think I understand you now, thanks So, with 2 diodes and 2 effective banks of 7135 chips, each diode protects 1 bank of 2 chips, right? So, if you replace one of the diodes with a blinky, it's only going to allow current to flow when the blinky circuit is closed/ on, essentially an on/off diode. Therefore any 7135 chips on the bank "protected" by that blinky are only going to sink current when the blinky circuit is closed/ on. Does that sound right?

    Here's the board I'm using
    http://kaidomain.com/Product/PhotoGa...03/182498#id=2

    which has 1 bank and 1 diode, but with a space for a second diode and bank of chips. So all I'd need to do would be to relocated one of the 7135 chips to the other bank and wire the blinky into that bare diode spot.

    One question though - given that the max current of the blinky is ~30mA, wouldn't running 350mA through it kill it pretty quickly?

  41. #41
    mtbr member
    Reputation: manokaiser's Avatar
    Join Date
    Jun 2008
    Posts
    163
    That's right matt.
    The current through the Power Led is not the same as through the Vdd input. A few mA on the input are enough to turn the chips ON and allow the Power Led high current pass through Ground to Led+.

  42. #42
    mtbr member
    Reputation: mattthemuppet's Avatar
    Join Date
    Jul 2004
    Posts
    2,374
    awesome! I'm slowly starting to understand how these things work. Hopefully I now have enough understanding to make it actually work Looking again at the driver circuit diagram it becomes pretty clear - the LED+ come right from the B+, the LED- goes to the 7135 out and the chip sinks the current to ground. The diode to the Vdd comes off the B+ (same as the LED+) to the Vdd and provides enough voltage (but little current) for the 7135 to sink current from the LED.

    Phew, I need to go lie down..

    Fingers crossed I'll get to give this a whirl tonight (after fixing my commuter's mud guard and swapping an optic in my helmet light), so I'll take some pictures as I go. Fingers AND toes crossed!

  43. #43
    mtbr member
    Reputation: mattthemuppet's Avatar
    Join Date
    Jul 2004
    Posts
    2,374
    so, I found some time last night to have a fiddle. Turns out I'd put the 2 7135 chips on separate banks, so although the Vdd pins all share the same diode I was able to cut the trace to one bank. Touching the short leg of the blinky (+ leg was already soldered to B+) to the Vdd trace on the cut bank produced exactly what I was after - on and flashing I could also just see the blinky flashing too.

    Sadly, I think with all my futzing around in the dark showing it off to my wife I ended up shorting that 7135 chip as it stopped flashing I'll have to swap it with a spare 7135 and solder everything up properly this time!

  44. #44
    mtbr member
    Reputation:
    Join Date
    Nov 2011
    Posts
    27
    Matt, let me get this right, you are de-soldering the 7135 and moving the chip to a new location across the board ? or are you just de-soldering the Vdd leg and putting the blinky in series with the leg ?

    nice job !

  45. #45
    mtbr member
    Reputation: mattthemuppet's Avatar
    Join Date
    Jul 2004
    Posts
    2,374
    sort of. I bought 5 350mA drivers from KD (see the link above), but then decided that 700mA would be nicer so added an extra 7135 chip to one of the empty spots. As there are 2 "banks" of 2 spots each side of the LED- pad and diode, you could either have 2 chips on one side/ bank or one chip on both sides. On one driver I had two on one side (no good), on another I had one on both sides. As the Vdd trace goes from the diode to both banks, all I did was cut the trace going to one bank.

    This would normally result in the 7135 chip on that bank not working (no Vdd voltage signal), but by wiring the blinky from B+/LED+ to the cut Vdd trace, every time the blinky was on, the cut Vdd trace would receive a voltage signal and the 7135 chip would sink it's 350mA of current.

    Sadly, I think I shorted the 7135 chip on the cut trace bank, so I need to replace it with one from the other driver (or rejig the other driver so it has a chip on each bank).

    As soon as it's properly wired up I'll take some macro shots to show what's going on

  46. #46
    mtbr member
    Reputation: manokaiser's Avatar
    Join Date
    Jun 2008
    Posts
    163
    So here is the Blue Led (video) driven by my favorite blinky type. The pulses are shorter. This light looks more like jewellery
    It uses 3x7135 driver and the original circuit without the resistor. All 3 chips are driven by the blinky.

    So it works either way, even with a single chip.
    Attached Thumbnails Attached Thumbnails On and flashing-1636.jpg  

    On and flashing-1637.jpg  


  47. #47
    mtbr member
    Reputation: mattthemuppet's Avatar
    Join Date
    Jul 2004
    Posts
    2,374
    finally got off my sorry butt and finished the light - it's awesome! Thanks so much for your help monokaiser, I'd never have figured it out on my own

    http://forums.mtbr.com/lights-diy-do...ml#post9006968

Similar Threads

  1. Still need a heatsink for flashing XP-G??
    By Bryank930 in forum Lights DIY - Do It Yourself
    Replies: 5
    Last Post: 01-02-2011, 08:28 AM
  2. Red lights flashing...
    By Ogre in forum California - Norcal
    Replies: 8
    Last Post: 11-08-2007, 02:10 PM
  3. MTBR Flashing?
    By mtnfiend in forum Site Feedback/Issues
    Replies: 4
    Last Post: 01-29-2006, 05:15 PM
  4. MTBR Flashing?
    By mtnfiend in forum General Discussion
    Replies: 2
    Last Post: 01-19-2006, 11:44 PM
  5. Protege 9.0 computer flashing
    By Some Guy in forum General Discussion
    Replies: 3
    Last Post: 09-13-2005, 11:26 PM

Members who have read this thread: 0

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

THE SITE

ABOUT MTBR

VISIT US AT

© Copyright 2020 VerticalScope Inc. All rights reserved.