Arduino Daisy Chain 5V power & ground

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kiwis

828 posts

Ultimate Geek

#296202 29-May-2022 20:46

I'm trying a new switch board using an Arduino board. The only issue is I have more switches which required the 'power' supply than female ports available on the board. I understand the way around this and the need for ground power is to 'daisy chain' them. I've also been told to solder them.

Long term all good but as a trial - is there a better way? Something like these?

https://www.jaycar.co.nz/16-way-idc-line-socket/p/PS0985

https://www.jaycar.co.nz/60-amp-12-way-screw-terminal-strip/p/HM3204

https://www.jaycar.co.nz/cables-connectors/terminal-blocks-headers/c/1H?sort=popularity-desc&q

Any ideas? I have a heap of F-M jumpers.

elpenguino

3343 posts

Uber Geek

#2920176 29-May-2022 21:45

A handy way to make temporary connections is a breadboard: https://www.jaycar.co.nz/mega-prototype-shield-with-breadboard-for-arduino/p/XC4416?pos=3&queryId=9a2880e93ca401f5f8de09fec419545d

The white bit shown in the photo.

The breadboard usually has a long connector side suitable for + DC and another strip opposite suitable for ground.

I wouldn't recommend the one shown, but a larger one with power strips as well, like this https://www.aliexpress.com/item/32711841420.html?

Soldering the power to the switches in a daisy chain will work too, but be less flexible. You can always unsolder things so no big deal really.

Most of the posters in this thread are just like chimpanzees on MDMA, full of feelings of bonhomie, joy, and optimism. Fred99 8/4/21

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richms

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#2920185 29-May-2022 22:30

Just twist and put into a chocolate block connector or use a wago for testing. Once you have everything how you want it then you can make it permanant with soldered wires.

The wagos like Jaycar sell (which I assume are clones like everything else there) will take 4-5 of the little header wires twisted together per hole and do a good enough job for signal level stuff like input buttons etc.

Richard rich.ms

kiwis

828 posts

Ultimate Geek

#2920269 30-May-2022 07:44

Thanks for the replies,

Do the pins stay secure in a breadboard? I’m wondering if this is only testing or could it be left like this for a few weeks while some user testing was done?

Out of interest would this work?

One wire from Arduino to first pin then next 9 out to each switch?

Do the same for Ground and 5V

https://www.jaycar.co.nz/10-pin-0-1-header-with-crimp-pins-2-54-pitch/p/HM3410

Otherwise, in true daisy chain - could I not twist 3 naked wires together then slide over a jacket and heat shrink it?

The wires being
1: 5V out from Arduino
2: Into first switch
3: off to second split and becoming wire 1 in next junction

elpenguino

3343 posts

Uber Geek

#2920296 30-May-2022 09:29

Yes, wires stay secure in a breadboard. But, you can pull them out so they're not permanent or suitable for movement - but for a breadboard sitting on your desk, they'll stay there.

You can connect the wires/switched in multiple configurations - for what you're doing, the method or order of connection will make no difference.

In this scenario, you should use a current limiting resistor when you connect the first of the switches to the Arduino 5V. If you short the 5V to ground without the resistor you will smoke something.

100 - 1000 ohms

Most of the posters in this thread are just like chimpanzees on MDMA, full of feelings of bonhomie, joy, and optimism. Fred99 8/4/21

itxtme

2102 posts

Uber Geek

#2920299 30-May-2022 09:52

Legit Wago 221's take male pins no issue, so thats an easy way forward if you are just testing and not wanting to strip wires

kiwis

828 posts

Ultimate Geek

#2920332 30-May-2022 12:10

itxtme:
Legit Wago 221's take male pins no issue, so thats an easy way forward if you are just testing and not wanting to strip wires

So you think a handful of these would work on a semi short term basis?

https://www.jaycar.co.nz/3-way-wago-splice-terminal-block/p/HM3235

So 5V into one of these, one to the switch the final one off the the next Wago??

Breadboard could work but if it gets bumped or moved it’s all likely to fall apart.

kiwis

828 posts

Ultimate Geek

#2920334 30-May-2022 12:14

elpenguino:

In this scenario, you should use a current limiting resistor when you connect the first of the switches to the Arduino 5V. If you short the 5V to ground without the resistor you will smoke something.

100 - 1000 ohms

Regarding the resistor this is a very interesting point. I am very new to this and I’ve been playing with the absolute basics. Essentially I’m making a control panel with a series of switches connecting to an Arduino board which is powered vis USB into my PC.

The Arduino board only has the one 5V port. I’m not even sure what level of power it supplies.

Given all my switches and LEDs need power I was going to daisy chain the cable across them all. Do I still need to do this and how would I work?

elpenguino

3343 posts

Uber Geek

#2920354 30-May-2022 13:09

Your LEDs need power to work but the switches presumably go to GPIO inputs and therefor the GPIO inputs only need to see a change in voltage (input current is minimal).

BY all means run the same 5V to everything if you want, but if you can separate the switch 5V from the LED 5V, do so.

How many LEDs do you want to run?

Each one needs ~20mA and the regulator onboard your Arduino can probably not supply too many.

Which Arduino board are you using?

Most of the posters in this thread are just like chimpanzees on MDMA, full of feelings of bonhomie, joy, and optimism. Fred99 8/4/21

kiwis

828 posts

Ultimate Geek

#2920534 30-May-2022 17:05

elpenguino:

Your LEDs need power to work but the switches presumably go to GPIO inputs and therefor the GPIO inputs only need to see a change in voltage (input current is minimal).

BY all means run the same 5V to everything if you want, but if you can separate the switch 5V from the LED 5V, do so.

How many LEDs do you want to run?

Each one needs ~20mA and the regulator onboard your Arduino can probably not supply too many.

Which Arduino board are you using?

I'll be used 3 8 digit boards off a Arduino Mega. I believe that should work.

I'm not sure what the -20mA is and a regulator.,, the online tutorials I've been watching don't show this.

richms

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#2920536 30-May-2022 17:10

The Arduino only regulates the 7+ volt input to 5v, if its run off USB then there is good current available for things. In the case of some of the cheap multiport chargers and desktop PCs often too much current available.

You able to provide more details about this project?

Richard rich.ms

kiwis

828 posts

Ultimate Geek

#2920544 30-May-2022 17:45

richms:

The Arduino only regulates the 7+ volt input to 5v, if its run off USB then there is good current available for things. In the case of some of the cheap multiport chargers and desktop PCs often too much current available.

You able to provide more details about this project?

So I'm going to use these boards I think. They say 5V here.

https://www.trademe.co.nz/a/marketplace/electronics-photography/other-electronics/electronic-components/leds/listing/3617461581

Arduino Clone Board will be this

https://www.trademe.co.nz/a/marketplace/electronics-photography/other-electronics/electronic-components/other/listing/3617472485

So both say 5V.

So based on this there's no need to regulate the power is there? I don't believe 3 boards running at the same time draws 15V via the board or anything.

It's a simple control box to work with MSFS. I'll use MobiFlight software.

https://www.mobiflight.com/en/index.html

I think controlling auto pilot takes me away from my standard view at critical times so brining it onto a desktop will help keep the emersion going.

richms

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#2920604 30-May-2022 19:17

The consumption of those matrix displays is minimal. you should be able to run 10+ of them easily so long as the software supports it, they pass all pins thru them so no need to common things together, just take the pins the out end of one to the in end of the next one. I have 40 of the 8x8 matrix ones connected end to end and it still updates ok from the device driving them for scrolling text, and plenty of voltage still at the end of it all.

If this is on a PC port then you will not be at risk of overheating the regulator on the Arduino as that's only used for the DC jack to bring it down to 5v. There is a 3.3v on the Arduino that overloads easily, but you're not using that so you are all good there.

Richard rich.ms

kiwis

828 posts

Ultimate Geek

#2920807 31-May-2022 11:14

richms:

The consumption of those matrix displays is minimal. you should be able to run 10+ of them easily so long as the software supports it, they pass all pins thru them so no need to common things together, just take the pins the out end of one to the in end of the next one. I have 40 of the 8x8 matrix ones connected end to end and it still updates ok from the device driving them for scrolling text, and plenty of voltage still at the end of it all.

If this is on a PC port then you will not be at risk of overheating the regulator on the Arduino as that's only used for the DC jack to bring it down to 5v. There is a 3.3v on the Arduino that overloads easily, but you're not using that so you are all good there.

Very good to know, thanks for the reply.

Out of interest, what is the in and what is the out or does not not matter. There's no label to this effect.

There is a difference, on the left the port labels on the top, on the right, they're on the other side.

richms

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#2920809 31-May-2022 11:17

One end has DOut, One end has DIn on them. The other pins are all passed straight thru. Arduino output goes to the first ones in, then its out to the next ones in. Software has to support cascadable displays to do that and be told how many there are so it can update them all at the same time.

You generally get a 5 way cable with each of those boards that should just go end to end between them.

Richard rich.ms

kiwis

828 posts

Ultimate Geek

#2921016 31-May-2022 16:16

richms:

One end has DOut, One end has DIn on them. The other pins are all passed straight thru. Arduino output goes to the first ones in, then its out to the next ones in. Software has to support cascadable displays to do that and be told how many there are so it can update them all at the same time.

You generally get a 5 way cable with each of those boards that should just go end to end between them.

Legend. Those boards also came with pins which can be soldered in place. I will have to purchase a cheaper soldering iron. As for the solder itself, is there a particular type i should get for small hobby projects like this?