8 Channel Relay Switch Build Thread

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mickdundee63
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Re: 8 Channel Relay Switch Build Thread

Post by mickdundee63 »

Thanks for all the information in this thread Joe, it's helped me figure out most things. I'm still confused on the regulator though - If I'm using a 24v supply and 24v relays is there a need to use the regulator?

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Joe Malone
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Re: 8 Channel Relay Switch Build Thread

Post by Joe Malone »

mickdundee63 wrote:
Thu Aug 25, 2022 12:06 am
Thanks for all the information in this thread Joe, it's helped me figure out most things. I'm still confused on the regulator though - If I'm using a 24v supply and 24v relays is there a need to use the regulator?
No the reg is just if you need to run relays that are lower voltages then the power rail. This is more for when the power rail is shared across several of our pcbs for different things.
Joe :-)
JLM Audio
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mickdundee63
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Re: 8 Channel Relay Switch Build Thread

Post by mickdundee63 »

Joe Malone wrote:
Thu Aug 25, 2022 8:36 am
mickdundee63 wrote:
Thu Aug 25, 2022 12:06 am
Thanks for all the information in this thread Joe, it's helped me figure out most things. I'm still confused on the regulator though - If I'm using a 24v supply and 24v relays is there a need to use the regulator?
No the reg is just if you need to run relays that are lower voltages then the power rail. This is more for when the power rail is shared across several of our pcbs for different things.
Ok great, thanks for such a quick reply Joe. So I can just bridge pins 1 - 4 and 13 - 16, then take the 24v from any of pins 13 - 16 to run via spst to whichever channels I want to switch?

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Joe Malone
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Re: 8 Channel Relay Switch Build Thread

Post by Joe Malone »

mickdundee63 wrote:
Thu Aug 25, 2022 10:58 am
Joe Malone wrote:
Thu Aug 25, 2022 8:36 am
mickdundee63 wrote:
Thu Aug 25, 2022 12:06 am
Thanks for all the information in this thread Joe, it's helped me figure out most things. I'm still confused on the regulator though - If I'm using a 24v supply and 24v relays is there a need to use the regulator?
No the reg is just if you need to run relays that are lower voltages then the power rail. This is more for when the power rail is shared across several of our pcbs for different things.
Ok great, thanks for such a quick reply Joe. So I can just bridge pins 1 - 4 and 13 - 16, then take the 24v from any of pins 13 - 16 to run via spst to whichever channels I want to switch?
If you put 24v direct into the ULN2803 inputs which are basically 2k7 impedance. Each input will draw about 9mA heating up the ULN lots. So best to use series resistor like 20k or 10k to each input so current per input is only 1 or 2mA.
Joe :-)
JLM Audio
Capturing Audio without Injury

mickdundee63
Posts: 3
Joined: Sun Aug 21, 2022 12:59 am

Re: 8 Channel Relay Switch Build Thread

Post by mickdundee63 »

Got it! Thank you
Joe Malone wrote:
Thu Aug 25, 2022 1:07 pm
mickdundee63 wrote:
Thu Aug 25, 2022 10:58 am
Joe Malone wrote:
Thu Aug 25, 2022 8:36 am
No the reg is just if you need to run relays that are lower voltages then the power rail. This is more for when the power rail is shared across several of our pcbs for different things.
Ok great, thanks for such a quick reply Joe. So I can just bridge pins 1 - 4 and 13 - 16, then take the 24v from any of pins 13 - 16 to run via spst to whichever channels I want to switch?
If you put 24v direct into the ULN2803 inputs which are basically 2k7 impedance. Each input will draw about 9mA heating up the ULN lots. So best to use series resistor like 20k or 10k to each input so current per input is only 1 or 2mA.
Got it! Thank you

Gold
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Re: 8 Channel Relay Switch Build Thread

Post by Gold »

Hi Joe,

I was wondering if you might be up for designing a companion board that had the logic to make this into a 4:1 stereo balanced source selector? Using momentary action pushbutton switches and including the LED drivers. I think others might find that useful as well.

Thanks,
Paul
Paul Gold
Salt Mastering

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Joe Malone
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Re: 8 Channel Relay Switch Build Thread

Post by Joe Malone »

Gold wrote:
Mon Nov 27, 2023 5:47 am
Hi Joe,

I was wondering if you might be up for designing a companion board that had the logic to make this into a 4:1 stereo balanced source selector? Using momentary action pushbutton switches and including the LED drivers. I think others might find that useful as well.

Thanks,
Paul
HI Paul
Interesting as I am working on a digital control relay volume using an Arduino nano etc for control so users can customise it so would be fairly easy to do in and out switching control from the same CPU. I will have a look at it.

Also have attached a new relay pcb which is perfect for switching 4 x 2 input or outputs and uses our simple STBUS 10 pin connection. You can ribbon cable directly across the 4 10 pin header to make 4 to 1 or 1 to 4 switching.
You do not have the required permissions to view the files attached to this post.
Joe :-)
JLM Audio
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Gold
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Re: 8 Channel Relay Switch Build Thread

Post by Gold »

Thanks Joe!
Paul Gold
Salt Mastering

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