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Can you be more specific sir? Please. I'm having trouble understanding it. Thank you @UKHeliBob
Project Guidance / Re: Bluetooth (HFP and A2DP) A...
Last post by 1soproni - Today at 03:13 pm
Is there any progress? I need something similar
max7219 is designed for driving leds. It's pins can source and sink more current. They are constant current outputs, which means that no led series resistors are needed. One resistor sets the current for all leds. Also, the chip performs multiplexing, which means that the Arduino does not have to perform this task, as is needed with 74hc595.

74hc595 is a general purpose logic chip. Its pins are designed to drive the inputs of other logic chips. This does not require as much current as driving leds.

74hc595 cannot be used to drive 16 leds in series. That would require a supply voltage of perhaps 36V or more, which would destroy the chip. Perhaps you meant to say that you used 2 x 74hc595 to drive 16 leds, one led connected to each output pin.

With your matrix, one 74hc595 pin is driving 8 leds in parrallel. This requires too much current, which causes the dimming, and will also damage the chip.

To prevent the dimming, you must chose series resistors which limit the current for 8 leds to less than 35mA, or 4mA per led. This is the maximum current that a single output of the 595 can source or sink. For red leds with a forward voltage of 2V, and a supply of 5V, your series resistors would need to be (5-2)/0.004 = 750R. This would make the matrix quite dim, but would prevent the dimming effect you have seen.
In your last line you said "this would make the matrix quite dim but would prevent the dimming" ??? Actually the problem is leds are dim???
Something else I'll mention to the OP here, is that if you do "play around" with a MOSFET in the way I mentioned, and things seem to get a little weird as in the thing conducting while the gate is pulled low, note that the gate diode "can" be accidentally blown while "experimenting." To determine if it has been, simply connect the "diode check" function of your multi-meter between the gate and drain and if it's open then it's blown. :-(
Bar Sport / Re: [OT ITA] Lo spamm bar
Last post by Etemenanki - Today at 03:12 pm

... ci sono pure i pasticceri spiritosi ...

Deutsch / Re: Daten von der Arduino-Seri...
Last post by postmaster-ino - Today at 03:11 pm

Das hier:
müsste in die gleiche Richtung gehen.
Bei <15 Sekunden Update-Intervall wohl unentgeltlich nutzbar.

Deutsch / Re: LCD Menu für UNO erstellen
Last post by HotSystems - Today at 03:11 pm
Ein US Sensor der die Weite erkännt hätte ich.
nur das abfragen wäre wohl mein problem, ich müste auch noch ein 74HD 595 einsätzen weil ich keine Pins mer habe.
Einen US-Sensor kannst du nicht an einem Schieberegister betreiben.
Den musst du direkt am Arduino betreiben.
Audio / Re: playing audio with servo
Last post by CrossRoads - Today at 03:10 pm
Simple example
Code: [Select]

// the setup function runs once when you press reset or power the board
void setup() {
  // initialize digital pin LED_BUILTIN as an output.

// the loop function runs over and over again forever
void loop() {
  digitalWrite(LED_BUILTIN, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);                       // wait for a second
  digitalWrite(LED_BUILTIN, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);                       // wait for a second
  if (Serial1.available() > 0) {
    byte data1 =; 
    Serial1.print("read in: ");  
    Serial1.write (data1);            

Change 1 to 2 or 3 depending on which pins are used.
Serial1, Serial2, and Serial3 are typically used for uC to uC comms's, and will not show up on the Serial monitor unless an FTDI Basic/equivalent is connected to them to talk to the PC
Displays / Re: Max72xxPanel question.
Last post by TonyWilk - Today at 03:09 pm
That code looks like something for a scrolling message display, which now doesn't work. I can't make any sense of the date/time stuff.

Are you wanting to show a static message or a scrolling one?

What exactly do you want to show ?

Project Guidance / Re: Self Plant Watering System
Last post by sprinkfitter - Today at 03:08 pm
There are many kinds of soil moisture senors - usually based on conductive or capacitive sensing. The first will corrode fast if you keep them powered at all times.
Would you have a recommendation on witch one to use. 
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