Help with PCB

Other Hardware General Electronics
1

Hello everyone,

I am looking to have a PCB made for the attached simulation and I have following questions for someone with the PCB experience,

  1. How many layers and area/dimension would i require?
  2. what is a better option between through hole and surface mount?
  3. Do i need to have separate layers for power and ground?
  4. Any suggestions how to get this done efficiently once i have the gerber files ready?
  5. Best ways to power the Arduino?

I don't have any specific requirements and just want to have PCB made which i can solder parts and hang it on a wall in a frame. Anything above the MOSFET's and relays are not included in the PCB.
Thank you for your time and looking forward to hearing from you.

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2

Could easily be done on 1 or 2 layers

Thru hole is easier to solder by hand, SMD requires special tools and techniques

No separate layers needed for power and ground, ground pours are good

You can order PCB or make them yourself

He’s way to power this would be a plug because the relay require significant power

3

Hi,

Thank you for responding. Anything above the MOSFET's and relays are not included in the PCB. About layers, you're saying two layers for traces (bottom) and component mounting (top)?

4

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If you are making this PCB yourself, a single side board would be sufficient.

Even if a few jumpers were needed, a SS board for DIY people is preferable.

If you get the PCB in China ???, a double side board is the way to go.

You can either use screw terminals or headers to take signals to external components.

Suggest you use an ‘Arduino Pro Mini’ ~$2.00 (same as an UNO) for the controller used as a daughter card on a mother’s board.

Note: there are many Pro Mini footprints out there so order your Pro Mini (with spares) first to make sure you use a footprint that will work.

A ‘Buck Converter’ (connected to the 24v) as a daughter card probably would work.

Or, you could power the Arduino from a 5 volt cell phone charger.

5

Hi larryd,

Thank you for the rescue always :slight_smile: I am going to order the PCB online. They were asking for layers and dimensions and I wasn't sure.

"suggest you use an 'Arduino Pro Mini' ~$2.00 (same as an UNO) for the controller used as a daughter card on a mother's board" I didn't get it. I have already received Arduino UNO R3 (ordered 6 of them :smiley: )
Only waiting on optoisolators and Mosfet's scheduled to be deliever on Monday. Now I was looking for a PCB made while i test it on a breadboard and try to make the gerber files for the first time :grinning:
I might just use the cellphone charger for power.

6

Which MOSFET (part number) did you order ?

Show us your board layout before you order it.

7

Parts i ordered:

https://www.digikey.com/products/en?keywords=fdpf39n20-nd
https://www.digikey.com/products/en?keywords=160-1304-5-nd

Any suggestions for the board layout?

8

That MOSFET is not made for logic level operation.

You need a ‘logic level’ MOSFET that can be switch with 5v (logic levels).

Suggest the following:

  • mounting holes in the corner.
  • on board LEDs to show when the MOSFET is ON/OFF.
  • LED to indicate 24v is present.
  • LEDs to show when the relay contact is closed.
  • maybe a Heartbeat LED to show the Arduino program is running.
  • header pins to connect to the Arduino.
  • screw terminals for solenoid and relay connections.
  • the kickback diodes should be mounted at the solenoids.

Okay I’ll add the LEDs suggested above to the schematic for you, a bit later.

9

The MOSFET you suggested earlier was not available in “through hole”. It was only available in surface mount. I forgot the logic level part, I’ll dig more.
Thank you for the suggestions.
Note: this pcb will be mounted mounted to n the wall and the connections between press and mixing station will be made through terminal blocks and PCB.
Do you think the arduino should be mounted on the pcb too?

10

Do you think the arduino should be mounted on the pcb too?

No

I think everything is covered in the schematic now, you can check it and get back with comments.

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EDIT

Updated schematic

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11

Hi larryd,

Thank you for sharing your precious time and helping me out. I have few questions.

  1. What software you used to make this schematic and can you send me the schematic file in case i need to change the labels/circuit.

  2. What software will you suggest to create the gerber files.

  3. Can i use tip 120 instead of logic level Mosfet. How much difference will it make? If it's necessary I'll find them (logic level).
    Also I have found this part for LED. Can you tell if it'll work
    https://www.digikey.com/product-detail/en/visual-communications-company-vcc/5300H7/L20017-ND/59972
    otherwise please suggest the parts. I have received all the parts except mosfet (i have TIP 120 and power MOSFET) and led.

  4. The LED e.g 24V led have 220 ohm with 24v. It won't burn out?

  5. The heartbeat LED is already programmed with our code?

Thank you!

12

OK. But what is the purpose of this whole circuit ?
It appears that you use an Arduino pin to switch on an relay which drives an opto-coupler which switches another Arduino pin and all that 3 times.

13

  1. The PCB software I use is no longer available.

  2. Most people here use the “EAGLE” PCB program for schematic drawing and making Gerber files.

  3. You can use the TIP120 BJT but the MOSFET is soooooo much better, you can use the same schematic.

  • Use case style TO220, MOSFETs N channel: IRL540 or IRL3705 or IRLZ44N or NDP6020
  • Any T1 3/4 LED should work fine.

  1. All LED resistors can be 2.7k. The Heartbeat LED is 220R.

  2. Heartbeat code is in the sketch already.

Schematic changes to follow:

14

6v6gt:
OK. But what is the purpose of this whole circuit ?
It appears that you use an Arduino pin to switch on an relay which drives an opto-coupler which switches another Arduino pin and all that 3 times.

The Arduino controls 3 solenoids (not relays) in the machine.

The 3 'Presses' each have a relay contact that closes when that 'Press' needs material.

The Solenoid 'is not' part of the Press's relay circuit.

I think :confused:

15

@6v6gt:
The circuits controls three presses and a mixing station. When a press needs material, it sends 24v on the relay and then through Arduino we turn on the solenoids using low side switching. The relay you see is the output of the press and the solenoid is input. The solenoid is NOT part of the press relay circuit. Let me know if you have any questions.

@larryd:

I have received T0-220F already so I'll use that then. The LED link i sent earlier should work if i get it right. About resistors, can you check R1 and R2 in the schematic and confirm if they're right?
Also D6,D7,D8 are directly connected to 24V.
can i get the schematic file and software name?

"Schematic changes to follow:" ?

Thanks

16

  1. The PCB software I use is no longer available.

  2. Most people here use the "EAGLE" PCB program for schematic drawing and making Gerber files.

  3. You can use the TIP120 BJT but the MOSFET is soooooo much better, you can use the same schematic.

  • Use case style TO220, MOSFETs N channel: IRL540 or IRL3705 or IRLZ44N or NDP6020
  • Any T1 3/4 LED should work fine.

  1. All LED resistors can be 2.7k. The Heartbeat LED is 220R.

  2. Heartbeat code is in the sketch already.

Schematic changes to follow:

MOSFETs

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BJTs

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You can use the same PCB for either MOSFETs or BJTs.

Updated the schematics.

2020-03-09_13-34-16.jpg
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2020-03-09_13-38-43.jpg
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17
  1. D6,D7,D8 are directly connected to 24 v. is that alright?
  2. Can i use 4.7k instead of 2.7k.

Thanks

18
  1. D6,D7,D8 are directly connected to 24 v. is that alright?

They first go to the PRESS relay contact (S1, S2, S3) which you said is connected to 24V inside the machine.

Just follow the signal paths up to the individual 'Presses'.

  1. Can i use 4.7k instead of 2.7k.

Yes, the LEDs will be a bit dimmer but should be okay.

19

Yes but R12,13,14 shouldn't be connected between LED and the relay?

20

umar_abbasi:
Yes but R12,13,14 shouldn't be connected between LED and the relay?

No

In a series circuit, ‘it doesn’t matter’ which component appears before the other.