I need help :(

I want startup six “8 channel relay” with five “arduino” and five “RF receiver” WITH one power supply 5V 10A or 15A .

one branch wire from power supply is for 8 channel relay1
one branch wire from power supply is for 8 channel relay2
one branch wire from power supply is for 8 channel relay3
one branch wire from power supply is for 8 channel relay4
one branch wire from power supply is for 8 channel relay5
one branch wire from power supply is for 8 channel relay6

one branch wire from power supply is for arduino1
one branch wire from power supply is for arduino2
one branch wire from power supply is for arduino3
one branch wire from power supply is for arduino4
one branch wire from power supply is for arduino5

one branch wire from power supply is for radio RF1
one branch wire from power supply is for radio RF2
one branch wire from power supply is for radio RF3
one branch wire from power supply is for radio RF4
one branch wire from power supply is for radio RF5

but i have problem , voltage for relays is weak , power supply is 5V but voltmeter show me 3.5 or 3.4 for relays . . . and sometime relay can’t action. . .
please help me :frowning: what am I do ?

Ground?

AWOL:
Ground?

hi thank you for answer
ground and vcc !!! all of ground(relays and arduinos and radios) connect to power supply GND and all of vcc (relays and arduinos and radios) connect to power supply VCC

can you provide links for the boards you are using ?

A schematic would be very helpful or possibly a photo if this is difficult.

Be aware that a photo will have to be resized to fit forum limits taken from most cmodern phones, or linked to by photobucket ETC.au

Boardburner2:
can you provide links for the boards you are using ?

A schematic would be very helpful or possibly a photo if this is difficult.

Be aware that a photo will have to be resized to fit forum limits taken from most cmodern phones, or linked to by photobucket ETC.au

Boardburner2:
can you provide links for the boards you are using ?

A schematic would be very helpful or possibly a photo if this is difficult.

Be aware that a photo will have to be resized to fit forum limits taken from most cmodern phones, or linked to by photobucket ETC.au

hi thank you for help me.
I dont have schematic . but this is very easy ...
this is my relays : (6)

arduino's are nano and a module RF.
i am connect "IN1-8 relay pin" to my arduinos digital pins(for all)
and connect data pins in radio to arduino digital pin

BUT my problem:
every GND and VCC in arduinos and relays and radios all of pins Joined together to VCC and GND my power supply . all of things is true and this is work correct with transmitter ...
just my problem is "voltage drop" for my relays !!! my power supply is 5V 10A but voltage for every relay is 3 or 3.5V !!!!!!!! :frowning:

BUT my problem:
every GND and VCC in arduinos and relays and radios all of pins Joined together to VCC and GND my power supply . all of things is true and this is work correct with transmitter ...
just my problem is "voltage drop" for my relays !!! my power supply is 5V 10A but voltage for every relay is 3 or 3.5V !!!!!!!!

Use a separate wire for each VCC and GND and terminate all at the 5V supply. Make sure there are no series connections such as GND from one relay module to GND of another. Also don't make series connections for JD-VCC.

I strongly suggest using a separate supply for your relay modules. You would then have no power problems with the Arduinos and could make use of the opto isolation feature of the relay modules. Here's how to connect them to acheive this:

this is a Simple shape

dlloyd:
Use a separate wire for each VCC and GND and terminate all at the 5V supply. Make sure there are no series connections such as GND from one relay module to GND of another. Also don't make series connections for JD-VCC.

I strongly suggest using a separate supply for your relay modules. You would then have no power problems with the Arduinos and could make use of the opto isolation feature of the relay modules. Here's how to connect them to acheive this:

hi my friend thank you for help me
i use a separate wire for each VCC and GND !!similar to my photo . I want try to use one power supply for all :confused: also your photo dont oopen for me please reload this, thank you

Here's the link.

dlloyd:
Here's the link.

thank you , but there is not any way for use one power supply ?
so for 6 arduino nano and 6 receiver RF , I need a power supply with how much A ?
and for 6 8ch relay power supply how much A ?

Yes one power supply would be fine and about 2A capacity.
Are you wiring 5V into the Vin pin of the Arduino? That would give you a reduced 5V rail. That would also be seen quite clearly if you provided a schematic and stopped waffling about.

Grumpy_Mike:
Yes one power supply would be fine and about 2A capacity.
Are you wiring 5V into the Vin pin of the Arduino? That would give you a reduced 5V rail. That would also be seen quite clearly if you provided a schematic and stopped waffling about.

hello yes i wiring 5v into the vin pin... similar to my pic .
also I a separate supply for relay modules but every time one relay will be on voltage reduse . two relays reduse more and . . .
what am i do !!? :frowning:

It looks to me a lot like you're trying to drive the relays directly from the I/O pin, with no buffering.

AWOL:
It looks to me a lot like you're trying to drive the relays directly from the I/O pin, with no buffering.

so this problem is for all and not me alone ?
one question !?
how much work voltage for a 5V relay ? max voltage that I can give to 5v relay?

As Grumpy_Mike already tried to explain: Connecting 5volt to V-in is WRONG.
The Nano only gets about 4volt that way.

Connect 5volt to the 5volt pin of the Nano.

Ignore the diagram from dlloyd if you are going to power everything from a single 5volt supply.
That diagram is if you supply the relay card from a separate 5volt supply (and want opto isolation).

Your diagram from post#6 is ok, as long as you move the supply for the Nano from V-in to the 5volt pin.

Show us a REAL picture of the setup if it doesn't work.
And your code.
Leo..

Just to mention that your six 8-channel relay boards will draw about 0.1A for each relay. With all relays energized, that's 4.8A.

If you decide later on to try the opto-isolation feature, there's a hidden benefit to this. With 5A load on the relay power supply, there'll be some drop in voltage, so make sure you use independent power rail wires. Note that the max range of voltage the relays will operate is 3.75V to 6V, so the relay modules can tolerate 25% drop from its separate 5V supply.

With opto-isolation, not only will there be added noise immunity, the Arduino boards will not see any of this voltage drop whatsoever.

thank you all friend <3
i use 2 power supply. this is more easy for me <3

Your problem is probably that the Nano doesn't put out 5v for data when you write those pins HIGH to activate a relay.

Unplug everything, only power up one Nano, write one of the pins HIGH, take your voltmeter, and measure the voltage output of that pin.

Let us know what you get.