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Topic: How to connect Arduino Uno, WS2812B and HC-05 to one external 5V power supply? (Read 219 times) previous topic - next topic

liork

Hi everyone

I'm trying to connect the followed components to only one external 5V/5A power supply:
1. HC-05 bluetooth device - Voltage: 4V to 6V, Current: 30mA.
2. WS2812B LED strip, 60 Leds, 3.6A consumption (60mA each).
3. Arduino UNO.

I connected all the components directly to the 5V/5A power supply, the arduino was connected through the 5V & ground pins.  all the components are connected toghether to the same '-' and '+' connections.
The problem is that HC-05 tend to disconnect after some seconds, and the connection is not stable.
I tried to use only few LEDs but the problem still occur.

I tried many ways the only one that worked for me was to plug the arduino sepparately to 5Vpower supply. The LED strip and HC-05 was connected to another 5V power supply.

Is ther a way to connect all of them to one power supply?

Thanks!!!   


Wawa

Post a diagram. And the code (use code tags).
Read the forum rules before you do.

A common 'mistake' is connecting the TX/RX of the BT module to pin 0,1 of the Uno.
A second on is leaving the two-resistor RX level shifter out.
(the HC-05 is a 3.3volt device, but powered from 5volt)
Leo..

Grumpy_Mike

Quote
I tried many ways the only one that worked for me was to plug the arduino sepparately to 5Vpower supply.
That suggests you need to make sure that the Arduino's power supply is decoupled from the interference the LEDs generate.

I would use the last circuit in this link http://www.thebox.myzen.co.uk/Tutorial/De-coupling.html

liork

Post a diagram. And the code (use code tags).
Read the forum rules before you do.

A common 'mistake' is connecting the TX/RX of the BT module to pin 0,1 of the Uno.
A second on is leaving the two-resistor RX level shifter out.
(the HC-05 is a 3.3volt device, but powered from 5volt)
Leo..
Hi Leo

Sorry it's the first time that I'm posting her, I don't know how to post a photo in the forum.
Please see the schematic on: https://ibb.co/k8o3PJ
1. The BT RX is connected to Arduino TX, The BT TX is connected to Arduino RX
2. The BT won't work when connected to 3.3V
3. What do you mean by RX level shifter?

Thanks
Lio

Wawa

1. The BT RX is connected to Arduino TX, The BT TX is connected to Arduino RX
Yep, most people do, because there are thousands of articles/images on the net showing this.
Expect problems if you don't know what you're doing, because those pins are also used (hardwired to) the USB<>Serial chip.
Better to use SoftwareSerial on two different pins. SoftwareSerial examples can be found in the IDE.

2. The BT won't work when connected to 3.3V
Did I say that? I said "powered from 5volt".
Bluetooth module POWER range is 3.6 to 6volt.
The processor on a BT board runs on 3.3volt, so the DATA signals are 3.3volt.

3. What do you mean by RX level shifter?
Two resistor (1k:2k or 1k:2k2), to drop 5volt data signal from a 5volt Arduino to a safe 3.3volt for the BT's RX pin.
Many examples on the net leave these out, expecting that the BT module will survive this abuse.
Dig a bit deeper on Google, and you will find the better examples.
Leo..

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