Uniden Smart Cord Schematic

Discussion in 'Uniden' started by dbranger94, May 8, 2018.

  1. dbranger94

    dbranger94 Learning to Drive General User

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    I basically took apart my smart cord and started reverse engineering it...

    6663da7375f85a7ca237bb9cd3dc987f.jpeg

    The red box is a +12V supply filter consisting of a 100uF Electrolytic cap and a smaller ceramic cap to filter ripple voltages(not sure the size without removing it from the board, likely 1-10uF).

    The blue box consists of basically a +5V power supply and some resistors for the USB charger. The chip, U1, is an HC8813 DC-DC step-down(buck) voltage regulator. R8-R11 are resistors that tell your device, such as a phone, to start charging when it's plugged in.

    The rest is what most of you are going to be concerned about. K1 is the momentary push button used to mute the detector. It has a capacitor, C5(1nF), to dampen it. The LED is fed by +12V and has a 6.8K ohm resistor. There's also an NPN transistor that is used by the detector to enable the LED when it's powered on and also flash the LED when there's an alert. I used a BC547 in my schematic below because its a TO-92 package and easy to solder or breadboard.

    Below is a quick schematic of how the push button and LED are wired.
    A = Alert which is the white wire in the Uniden cable
    S = Switch which is the green wire
    GND is black
    +12V is Red
    6663da7375f85a7ca237bb9cd3dc987f.jpeg
     
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  2. Up All Night

    Up All Night Premium Member Advanced User Premium Member

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    Last edited: May 8, 2018
  3. dbranger94

    dbranger94 Learning to Drive General User

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    I would assume that the Alert output in the detector is an open collector with a pull-up resistor. Then the output could be pulsed low for an alert. But there isn't a pull-up or pull-down resistor on the board. The alert output has to be high for the LED on the smart cord to activate.

    Hope that makes sense.
     
  4. dbranger94

    dbranger94 Learning to Drive General User

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    In your pictures I can see that the push-button is the same as before. Green "switch" wire to the push-button with a small cap to ground.

    They're also using two transistors on the alert LED so that it is off when there is no alert (Since they're using a separate power LED). If we assume the alert output is normally high(no alert), the first transistor(Q2) is switched on with the alert wire at its base and grounds the base of the second transistor (Keeping it off). The first transistor also has a 10K pull-up resistor on it's base to keep the alert LED off when there is no alert (As a backup? Or if the detector is unplugged?). The second transistor(Q1) also has a pull-up resistor on its base which switches on the transistor and grounds the LED when the first transistor(Q2) shuts off (When there is an alert).

    The LM393 is a dual comparator IC. Without being able to trace all the pins with a DMM I can only assume it's being used as a ground or current sensing circuit, and is used to enable the power led by grounding it if a certain condition is met.

    3cae469266b3d43f0b7efffee6877dab.jpeg
     
    Last edited: May 9, 2018
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  5. dbranger94

    dbranger94 Learning to Drive General User

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    I'm not sure that the R8 pull-up is necessary, I feel it's probably redundant. The LM393 technically isn't necessary either, as the power LED could be wired like any other LED.
     
  6. Bcoble1

    Bcoble1 TIPoGF Intermediate User Premium Member

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    So most of this is way over my head and I am doing my best to follow along because its interesting. Is there a way to make the LED light stay off until an alert just like the Escort cords?
     
  7. dbranger94

    dbranger94 Learning to Drive General User

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    On the cigarette lighter cords the simple answer is no. If you want to make your own cable, then yes.
     
  8. InsipidMonkey

    InsipidMonkey Premium Monkey Advanced User Acceptus Premium Member

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    This is great info @dbranger94, thanks for posting!
     
  9. Up All Night

    Up All Night Premium Member Advanced User Premium Member

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    One person said he figured out how to make the ecort work with his r3 but never posted how. I swapped some parts and got close but it was still slightly lite when off.


    Posted from my iPhone using the RDF Mobile App!
     
  10. dbranger94

    dbranger94 Learning to Drive General User

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    The not so simple answer @Bcoble1 is, you could split the white wire before the plug on the board and duplicate the second schematic above for the activity/alert LED. You would need an NPN transistor like a BC547 or similar for Q2 and a 10k ohm resistor for R6. Like I said before, I'm not sure R8 is necessary.
     
  11. LexusISF

    LexusISF Premium Member Advanced User Premium Member

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    Cool...
     
  12. CTMan

    CTMan Learning to Drive General User

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    Definitely thanks for posting. I need to take mine apart since the button broke barely a month after a bought it(Uniden wont replace since I didn't buy it from them and BestRadarDectectors.net, who I bought it from, isn't helping either).

    This may help me recoop my $30 and get it working again.
     
  13. dbranger94

    dbranger94 Learning to Drive General User

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    I went to Chattanooga this weekend and my mute button quit working also. I'm not sure why, must be the switch itself. I only used it a few times.
     
  14. TXLe

    TXLe TXCTG Intermediate User Premium Member

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    Any idea what the white J1 molex plug in the OP is for?
     
  15. InsipidMonkey

    InsipidMonkey Premium Monkey Advanced User Acceptus Premium Member

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    The RJ14 cable that runs to the detector.
     
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  16. CTMan

    CTMan Learning to Drive General User

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    It's disappointing that these seem so cheaply made and also that neither Uniden(won't replace since I didn't buy from them) or BestRadarDetector.net(doesn't seem to care as they first told me to goto Uniden then ignored my email asking if they would help since Uniden won't) won't help here.

    My cord was barely a month old and I think I used the button maybe 4 or 5 times. Luckily the cord still functions as a regular power cord for now.
     
  17. BestRadarDetectors

    BestRadarDetectors Premium Member Advanced User MFG/Vendor Premium Member

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    Not sure who you spoke with at Uniden but there is a warranty on them and they will take care of it. We are not the manufacture and we cant be expected to do warranty work on products that are not ours. If someone at Uniden tells you they cant help you get their name so we can have Uniden address it.

    Sent from my SM-G965U1 using Tapatalk
     
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  18. CTMan

    CTMan Learning to Drive General User

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    I sent them this...

    APR 26, 2018 | 03:57PM CDT
    Original message
    Charles wrote:

    I ordered the RDA-HDWKT on March 8th 2018 from BestRadarDetectors.net and today, when I pushed the mute button on it(probably only the 3rd or 4th time I've done so), it broke and no longer presses. For a short time the button was stuck in the on position, causing the R3 to put everything into the Mute Memory. I was able to make it stop but the button no longer works.

    What do I need to do for a warranty replacement?

    And here is the email I received from a support person "Ryan"...

    APR 26, 2018 | 04:19PM CDT
    Ryan replied:

    Good afternoon, Charles,

    We’re very sorry to hear that this has happened. Unfortunately Uniden has no warranty on accessories that are sold separately. We apologize for any inconveniences this may cause. I would recommend contacting BestRadarDetectors.com about this issue. Please feel free to contact us if you have any further questions or concerns.

    Thank you for Choosing Uniden!
    Ryan
    Uniden Tech Support
     
    Last edited: May 20, 2018
  19. kwthom

    kwthom Learning to Fly Beginner User

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    You mentioned an LM393 chip in this response. Where exactly is the LM393 being used? Obviously not in the Uniden Smartcord (as shown in post #1 of this thread) - part of the Hard wire Kit?
     
  20. InsipidMonkey

    InsipidMonkey Premium Monkey Advanced User Acceptus Premium Member

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    That quote was in response to the Escort smart cord pictures in post #2.