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Topic: So many possibilities to troubleshoot... Where do I begin? (Read 1 time) previous topic - next topic

CrossRoads

Connect HC595 OE/ to Gnd.
Get rid of any caps on control lines
Connect MSCLR to +5.
Put 0.1uF cap from Vcc pin to Gnd.
Right click HC595 symbol click INVOKE, will make Power & Gnd pins appear.
RCK is the Output register clock, LATCH connects to that.
ULN2004
http://www.ti.com/lit/ds/symlink/ulq2004a.pdf
can only drive its outputs low, so:
+5 to anode, cathode to resistor, resistor to  ULN2004 output.
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
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Loren

CrossRoads,

Wow thanks for all of the pointers.   I've made all of the appropriate adjustments to the schematic, but I do have one additional question:



ULN2004
http://www.ti.com/lit/ds/symlink/ulq2004a.pdf
can only drive its outputs low, so:
+5 to anode, cathode to resistor, resistor to  ULN2004 output.


I'm going to be using LED strips.  I thought I saw current limiting resistors on the strip.  If they have them on the strip would it be necessary to include them on this board?

Thanks again guys,

Loren

LarryD

The way you have it in your schematic isn't the same as how you have it wired up!


Caltoa

#9
Feb 05, 2014, 01:38 am Last Edit: Feb 05, 2014, 01:47 am by Caltoa Reason: 1
Those are not seperate leds, that is a led strip.
So you don't need the shift registers, and you don't need the ULN2004 drivers, you need to control a led strip.
Or do you want to control 8 led strips ?

Simple led strips can be controlled by a 12V pwm signal (or 3 for RGB color), some have a control chip.
I think you have a simple one.

The best way is to use 3 mosfets for a 12V pwm signal.
On this page:
http://www.pighixxx.com/abc-arduino-basic-connections/
Click on "Set 2 (Card 4,5,6)", look at card 5 how to control a led strip.
The orange label "OUT" is an arduino pin. So you need 3 pwm arduino pins, and that is all (for just one led strip that is).

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