For Sale RGB LED chaser PCB 16K flash, single battery supply possible

Discussion in 'Marketplace' started by takao21203, May 1, 2016.

  1. takao21203

    Thread Starter Distinguished Member

    Apr 28, 2012
    3,577
    463
    Many customers of CD4017 LED chasers have asked for programability.

    I found its possible to actually mount RGB LEDs to a LED matrix PCB I made.
    Since adding the 50 LEDs takes a long time, I didnt even test the dcdc converter.

    So here the details

    10 RGB LEDs
    Serial interface between display and MCU
    16LF1709 controller 16K Flash
    MCP1640 dcdc booster, adjustable (I did find small trimpots matching the PCB holes)

    Its possible to add a SOIC8 IC later, as well row headers or small parts.
    Most the IO ports are free.

    The price assembled is USD 25 + USD 4 shipping
    This is lowest possible price assembled.

    If you want a kit with all the parts, it costs USD 12
    Be aware the assembly may take you a long time, need to inspect all joints carefully.

    The PCB incl RGB LEDs fully works at 2.65 volts. So if you power it from a lithium battery, there is no 3.3V regulator by default. The controller can not be used with 5 volts supply.

    Other than blue LEDs turn on below 2.5 volts, so for instance 2xAA direct supply is possible and will last a long time.

    2- color LED red / blue, cost is USD 20

    Firmware

    In the video actually a text message is scrolled this gives random color patterns, repeating after a while.
    Also I have a source which I need to adapt, same function as a CD4017 chaser but changing between colors every once in a while.

    If you just want the DIY kit you will receive information about the PCB, and what to take care of when soldering the parts, as well information how to solder the SMD parts.

    Schematic

    Since there is serial bus on the PCB, its not needed.
    The MCU has no extra parts. There are a few 4.7uF capacitors.

    The display module is simply 16 bits shifting registers, MOSFETs on some port bits, and one blinking LED

    The dcdc booster schematic can be found in the datasheet.

    All information required for programming the LEDs can be found in the source code!
    Otherwise the IO ports are free and laid out 1:1 on the PCB. The serial port bits are also labelled on the PCB.

    Typical customers of these LED chasing circuits buy them ready made, but I was often asked for programability.
    For this only the firmware needs modification, not the integrated display driver or dcdc booster.

    https://www.instagram.com/p/BE3ryeOyfaA/
    https://www.instagram.com/p/BE33NZHyfTx/

    The LEDs are too bright to capture but look OK using a single AA rechargeable for some hours, and are very bright at 3 volts. So you could adjust the voltage in order to use the battery for a longer time.

    Havent tested the key input yet but today assembled a PCB anew with RGB LEDs.
    Im testing how long the battery lasts at low voltage.
    There are pads for 6 SMD keys.
     
  2. takao21203

    Thread Starter Distinguished Member

    Apr 28, 2012
    3,577
    463
    day two on single battery charge 1.2V 800 mAh

    Running almost 24 hours now. The voltage setting is quite low, less than 2.65v used for flashing.
    The blue LEDs barely turn on so maybe 2.4 or 2.45 volts.

    Operating superbright LEDs at low voltage, of course they only need a few mA.

    Probably you could do all this with Arduino, its cheaper. But Arduinos dont have a voltage booster or display drive. The 74XX ICs work fine at low voltage.

    I think something like the 16F1709 could be a starting point for 8bit controllers, dont pay so much attention the older ICs with small Flash. You couldnt animate RGB LEDs with them.

    This PIC has many new peripherals, most the IO is freely available, the display serial bus can be cut off physically if you wanted to.

    I could sell the PCBs just with controller, capacitors as breakout board, the ICSP is labelled, and you can add small parts.

    Why its in the fleamarket, well the LEDs some of the holes are too close to vias.
    There is one bug, the MCLR is input only. So it needs tiny wire bridge.
    But with the experience gained, I can make a better PCB next time.

    Adding the RGB LEDs is just an attempt to salvage this PCB. Soldering 50 LEDs doesnt make much fun when you need to take care vias for some. So I did let it sleep for months.

    How much did it cost to buy the parts and PCBs? LEDs as well? I dont know but a lot.

    https://www.instagram.com/p/BE6GkCpSfXC/

    You could examine the benefits
    -Using single battery + adjustable booster
    -Using low voltage controller 3v or less
    -Using a controller with large FLASH

    Mothball assembler perhaps. I really regret spending a lot of time with it.
    I remember the day I got the Velleman K8048 out of a mood.
    The documentation was a brain scorcher, RISC with few instructions.
    Then I even bought some PICs at high price, and started using assembler, as well
    trying to save program memory. That was 2004 or so.

    I wish someone had told me in a friendly manner to mothball assembler. There was no such guidance.
     
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