RGB led not fully litting up

Need Help With My Project
1

I’m currently working on 5050 RGB led strip , using RGB zerbra they are not fully dropping full current

Parts using

  1. Wemos D1
  2. S8050 NPN Transistor (also tried 2N2222)
  3. 74AHCT125N for converting 3.3 v to 5v logic level

When directly connecting r,g,b to ground , current reading is 1.10 A (for all three)

When connected through s8050 transistor , current reading is 0.88 A ( for all three)

Using 12v 10 amp power supply

Can anyone please help with the current drop…

2

Is your code using analogWrite commands?
If so, are you writing 255 or 1023 to the GPIOs to obtain maximum brightness?

ESP8266 based boards have have a 10-bit PWM, giving 1024 brightness levels, compared to an 8-bit PWM for Arduinos. So, if you use Arduino code and write 255 as the maximum brightness to your GPIO then you’ll only be getting a 1/4 duty-cycle.

Pete.

3

Thanks for your support

I’m writing 1023 to GPIOs

Screenshot_20210511-212214~2|447x500

4

Current reading per channel through transistor
R- 0.50 A
G- 0.41 A
B- 0.40 A

Max brightness ( Writing 1023 To GPIO )

5

So, you’re using digital pins in the app. I’m not really sure how that works with PWM via Blynk - I guess it depends on the board type you’ve chosen in the app, and what the Blynk library does with that data once it’s received.

Personally, I’d always use virtual pins in the app and handle the RGB control using analogWrite commands in the sketch.

Pete.

6

Ok I’ll try it with virtual Pin , :wave:

7

Tried with analogwrite function
Same result
Current drop - 0.85 A

Current I’m using BJT S8050 which is current control transistor

Should I use Mosfet ? , as it is voltage control and better for the application

Code used ;




#define BLYNK_PRINT Serial
#include <ESP8266WiFi.h>

#include <BlynkSimpleEsp8266.h>

#define R 14
#define G 12
#define B 13



char auth[] = "Jc0-5o1xduYr2aV0VQH6XLriRftx";
char ssid[] = "ssid";         // Your WiFi credentials.
char pass[] = "pass";    // Set password to "" for open networks.


BLYNK_WRITE(V1)
{
  int pinValue = param.asInt(); // assigning incoming value from pin V1 to a variable
  analogWrite(R, pinValue);
  
}

BLYNK_WRITE(V2)
{
  int pinValue = param.asInt(); // assigning incoming value from pin V2 to a variable
  analogWrite(G, pinValue);
 
}

BLYNK_WRITE(V3)
{
  int pinValue = param.asInt(); // assigning incoming value from pin V3 to a variable
  analogWrite(B, pinValue);
  
}

void setup()
{
  // Debug console
  Serial.begin(9600);

  WiFi.begin(ssid, pass);
  Blynk.config(auth, IPAddress(192,168,89,92), 8080);//, ssid, pass);
}

void loop()
{
  Blynk.run();
}
8

@Vedant please edit your post, using the pencil icon at the bottom, and add triple backticks at the beginning and end of your code so that it displays correctly.
Triple backticks look like this:
```

Pete.

9

Done :slight_smile: :slight_smile:

10

Yes!
Well, three actually.

Pete.

11

Or, you could make life simple and use an off-the shelf device and put your own Blynk code on it:

Pete.

12

Update

Test Results ;

Direct connection (R,G,B) - 1.14 A

Through S8050 BJT (R,G,B) - 0.86 A

Through IRFZ44N MOSFET (R,G,B) - 1.09

Though IRFZ44N it is not TTL (logic level) MOSFET , it requires around 9v to flow full current . That is not problem in my case as current is only approx 0.50 A per mosfet.

May be BJT should be use for very small current

:slight_smile: