Go Down

Topic: 2x Arduino: One as a power supply, One actioning 4 relays (Read 13594 times) previous topic - next topic

3AgL3_DeeJay

3AgL3 DJ Soft
We Make IT Happen

larryd

There still has to be a common ground from the Arduino to the ULN2803.
No technical PMs.
The last thing you did is where you should start looking.

3AgL3_DeeJay


There still has to be a common ground from the Arduino to the ULN2803.

I won't forget that.

I'm going in a few hours to a store to buy a couple of ULN2803s.
Test them a little, put together a scheme and come back with the results. :D
Thanks again!
3AgL3 DJ Soft
We Make IT Happen

larryd

Do you understand how the current will flow in this schematic?
No technical PMs.
The last thing you did is where you should start looking.

3AgL3_DeeJay


Do you understand how the current will flow in this schematic?

Yes! It's easy now that i saw the schematic. Thanks!!!

I went to the store but they didn't have the 2803 on the stock. I have to wait a few more days to get it. :(
Until then, i will do the final scheme. And this time, right. :D
3AgL3 DJ Soft
We Make IT Happen

3AgL3_DeeJay

I finished the schematics for the LEDs. I put the 2803 in the right way now...
But i don't know how to do the Relay connections. :(
My relays have to be always connected to a +5V line and a GND. Then i have to send a "HIGH" signal through the INT pin to switch the relay.
Since the 2803 only works by "switching" the GND line, i don't know how to use the 2803 with the relays.

I searched online for some examples, but all of them used the 2803 like this: power the relay coil from a +5V line, then run the GND line through the 2803 (like the photo from the attachment). And i can't use that... :(
3AgL3 DJ Soft
We Make IT Happen

larryd

No technical PMs.
The last thing you did is where you should start looking.

3AgL3_DeeJay


Show us a link to the relay you are using.


I don't have a link. I purchased them from a local store.
But here are some photos of the exact model i have.
3AgL3 DJ Soft
We Make IT Happen

larryd

Do you think this is the same?
http://www.aliexpress.com/store/product/2-Channel-Relay-Module-5V-for-PIC-ARM-AVR-DSP-wholesale-and-retail/707291_499450487.html
No technical PMs.
The last thing you did is where you should start looking.

3AgL3_DeeJay


Do you think this is the same?
http://www.aliexpress.com/store/product/2-Channel-Relay-Module-5V-for-PIC-ARM-AVR-DSP-wholesale-and-retail/707291_499450487.html


Yes! That's the one...
3AgL3 DJ Soft
We Make IT Happen

larryd

If you only have 4 realys to drive on the Adruino, don't use the 2803.
jumper JD-Vcc to VCC, Arduino +5 to relay VCC, arduino GND to relay GND, Arduino o/p pin to IN1 and IN2.
No technical PMs.
The last thing you did is where you should start looking.

3AgL3_DeeJay


If you only have 4 realys to drive on the Adruino, don't use the 2803.

In this stage a have only 4 relays. The finished project will have at least 10 relays...


jumper JD-Vcc to VCC, Arduino +5 to relay VCC, arduino GND to relay GND, Arduino o/p pin to IN1 and IN2.

That's how i used it so far...
But when i turn them on, i don't have 5V on Ardiono +5V pin anymore...
That's why i want to supply power for them from an external power supply (EPS).
So it will go something like this: connect the relay's VCC to the EPS +5V, the relay's GND to the EPS GND, and the INT1 and INT2 to the Arduino digital pins...
3AgL3 DJ Soft
We Make IT Happen

larryd

Connect the 2803 o/p to IN1 or IN2  then External +5V (not the Arduino +5) to Relay VCC/JD-VCC.
In this case a HIGH on the o/p of the Adruino will close the contacts.

Of course Arduino GND to relay GND to external supply GND.

With 10 relays use the 2803.
No technical PMs.
The last thing you did is where you should start looking.

3AgL3_DeeJay


Connect the 2803 o/p to IN1 or IN2  then External +5V (not the Arduino +5) to Relay VCC/JD-VCC.
In this case a HIGH on the o/p of the Adruino will close the contacts.
Of course Arduino GND to relay GND to external supply GND.
With 10 relays use the 2803.


After i saw your message, this is what i understand (keep in mind that i'm from Europe :D ):
- Connect 2803 o/p to IN1
- Connect EPS +5V to Relay VCC
- Connect ALL the GND line together
-> And what about the Arduino pin? Where to put that?

See the schematic:
3AgL3 DJ Soft
We Make IT Happen

larryd

Arduino O/P Pin 31 to 2803 pin 1
2803 pin 18 to relay IN1 or IN2

Relay JD-VCC to relay VCC to EPS +5V to 2803 pin 10.
Relay GND to Arduino GND  to 2803 pin 9.
No technical PMs.
The last thing you did is where you should start looking.

Go Up