How to go from an Arduino to a Custom PCB

Hi,

I have got my project’s prototype working on an arduino and am looking to minimise the size and cost of producing the project in future by making a custom PCB and having it manufactured. Has anyone had experience in making the jump?

Project is pretty basic:
TinkerCAD Project
In place of the LED will be the FemtoBuck receiving the PWM signal to control a strip of LEDs :slight_smile:

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Hi Dylan, Welcome to the forum!

I’ve made PCBs by hand back in 2008 with etchant pens and blanks, and photocopier transfer methods. With how cheap it is to get boards manufactured in China now I would highly recommend looking into a few of the manufacturers there. JLCPCB, PCBway and Oshpark come to mind.
I’ve used JLCPCB for a final year engineering project and the biggest cost and waiting time was based on the shipping method chosen.
I’ve used Altium designer on a university’s license which is great but far to expensive to consider buying myself.
Altium Circuitmaker is a free version that is not worth the frustration, it’s awful and I wouldn’t wish that upon an enemy.
I’ve heard Kicad is popular but haven’t used it myself.

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Hey @Dylan25284 - welcome to the forums!
You can get short runs of PCBs made up by several companies: OSHpark in the USA produce very high quality two-layer boards. There are several fab houses in China (JLCPCB, PCBWay).

My choice of PCB software is KiCad. It’s a free community project that is starting to give paid software a run for its money. There are plenty of tutorials online for getting started with KiCad - have a poke around and see which one works for you. As a shameless self-plug, here’s a zero-to-pcb series I made a little while ago (not affiliated with Core Electronics)

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Hi Michael,
Thanks for your reply :slight_smile: I gave the series a watch and will definitely follow it through when I get to that stage.

I’m more stuck with the steps before where your video kicks in. I’m not certain which components from the Arduino Uno needs to come with the external circuit to the custom PCB, or what I can use in place of the ATMEGA328 to keep the cost down. Are you able to help with where to start that process?

Hi Trent,

Thanks for the response mate, I really appreciate the advice.
I have designed the product for the PCB in Fusion360 and gave Eagle a try as it’s free for hobbyists, but will check out some that you mentioned as well :slightly_smiling_face:

Like I replied to Michael beneath, I’m more stuck with the steps before where your video kicks in. I’m not certain which components from the Arduino Uno needs to come with the external circuit to the custom PCB, or what I can use in place of the ATMEGA328 to keep the cost down. Are you able to help with where to start that process?

Hi Dylan.
PCB design:
Not so much these days but I personally have been using Sprint Layout by Abacom (Germany). A bit of a down side was no Autoroute. Abacom thought that so much work and change had to be done after the auto routing that it wasn’t worth the effort and the job may as well be started from scratch manually. Although I have not tried it I think the latest version does autoroute.

The circuit drawing mate to this is Splan which DID NOT capture and attach to Sprint Layout but with no Autorouting there was not much point. The latest version may do so now routing is available. I am not sure. Worth a look though. Dead easy to use and comprehensive and easy to get at libraries, also editing and make your own facilities. Well worth a look at ELECTRONIC-SOFTWARE-SHOP. Also the last time I purchased anything it was VAT free.

PCB manufacture.
I personally would not go any where China. Postage from there sucks big time. There used to be a couple locally advertised in Silicon Chip. I think one still does. I have used one in the past (don’t remember which one) and got excellent service. I had made a couple of errors re pad and hole size which he pointed out to me and corrected. He did not even want Gerber and drilling files. Quite happy with the Sprint Layout files only.
Cheers Bob

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Hi Dylan,

Since the Arduino is open-source, a good starting point may be to check out the schematics and base your supporting circuitry on that.

I can see why you’d like the integration between F360 and Eagle, and this is my bias creeping in, but Kicad is really slick, and is improving all the time. and the best part is you own your designs, they will never be held hostage.

Happy to rant about this all day, but that’s my 2 cents :slight_smile:
-James

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Hello Dylan,

You mentioned using something in place of the ATMEGA328 to keep the cost down. If your project is simple enough you could use the Attiny85 or the Attiny84. There are plenty of tutorials about using these chips and coding them with Arduino boards such as the UNO.

Regarding the external circuitry for the Atmega328 these links may help:

Hope this helps!

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Hi Jaden :slight_smile:

I haven’t been back to the forums in awhile as I was researching and was going to come back when I had a solution :stuck_out_tongue:

I think I have enough to present something so far, and coincidentally also went with an ATTiny85 ha ha

I found this video immensely helpful: Anything Arduino Part 2

Essentially I just needed someone to let me know that the Arduino is mostly just the ATMEGA328 and the external oscillator. The rest of the board is just so it can connect to the PC, have nice pin-outs, etc… I believe this is what @James was directing me to :smiley: I’d also like James to know I ended up using KiCad and found it much more user-friendly than Eagle, and will be sharing the design online once it is complete, in-line with the extremely helpful user-tutorial from @Michael KiCad - Zero to Hero

My circuit is now combining the schematics I put together with TinkerCad (PWM circuit), the schematic of the Femtobuck LED Driver (schematic under Documents), and added in a Polulo 5V, 500mA Voltage Converter to supply the ATTiny85 with 5V.

After putting it together in KiCad, I re-did it quickly in EasyEDA so I could order it from JLCPCB with the surface mount components already applied (I didn’t have the right parts in my KiCad model, I’ll fix this up before I post the finished product).

I’m currently just struggling with modifying the circuit to suit the shortage of AL8805W5-7 that every supplier seems to be experiencing. At this stage, I am likely going to transplant one from my spare femtobuck very carefully :neutral_face:

Pictures so far

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This is great! How good it’s going to feel to get a real thing that you designed in the mail. Welcome to the world of PCB fabbing.

Some immediate feedback: The outline and slot might not be delivered exactly as you designed. They will likely be approximated by the diameter of whatever routing bit JLC decide to use for the task - perhaps 1mm. That means the features indicated may be smoothed-out a bit.

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Thats Awesome Dylan!!!
Will the POT and switch pins act as some support for the regulator? That’s some super thinking!

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This is really cool! By the way, the image you attached helps a lot. Sketchy, but accessible and not burdened with unnecessary details.

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The 4 pins to the right of “V_REG” will still be there on the finished product as the voltage converter I purchased (linked above in previous post) will fit onto them :slight_smile: The ones for POT and SW1 at the top and bottom won’t be there, just the landing pads for wires that will lead to the respective parts mounted elsewhere in the frame of the lamp.

@Michael Definitely excited to see it arrive and hold it. Thanks for the feedback, they initially rejected it to have that middle slot expanded to 1mm width. I’ve thought about what I have done and already learnt from it :stuck_out_tongue: The entire bottom section was just to make the design large enough as they only pre-fab smt parts on boards at least 20mmx20mm. I figured I would add on a dummy part and break it off carefully after it arrived. Obviously now I realise I could have just made the bottom part a copy of the board and doubled the order. D’oh! So many lessons following this process through for the first time. Thanks for your videos and feedback :slight_smile:

I also found a replacement for the AL8805W5-7 which should work and I found some stock - the AP8803WTG-7. Has a lower value for the V_CTRL_HIGH value but should still recognise the PWM signal fine.

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