Wondering if PCBA is an option for me?

[Vitesze]

I know this is a bit of a longshot for people to answer as it’s very specific to my project - but given that I’m not particularly experienced with PCB design yet, I want to avoid wasting a lot of time on training myself, creating the design files etc. before finding out the answer to this myself.

Please see my project below:

It contains a Particle Electron, 5 sensor breakout boards, all powered by a D-cell battery. The cost per device is about $105 right now, and I’m aiming to produce between 250 and 500 of these over the next 12 months.

As you can probably figure, a big drawback for a setup like this is that a lot of time is spent soldering all the individual components - which also comes with the risk of human error. Therefore, I was wondering how difficult it would be for an inexperienced person like me, to take the current PCB design file (which I created), and embed the sensor breakout Eagle files into it and have it all manufactured somewhere in one go.

Specifically:
(1) Assuming I can find Eagle files for them, how hard would it be to embed the sensors into a PCB design? Is it just a matter of copy-paste, remove the thru-holes, and connecting the pins straight to my Electron?
(2) Would it be economically feasible to have only 250-500 PCBs like this produced and assembled? I don’t want to incur a lot of additional expenses, if it is substantially more expensive than doing it manually.

[chipmc]

@Vitesze,

I went through this exact same process. I am not sure if this works for you but here is what I did once I had a working prototype:

1. I designed a carrier board and sensor boards to reduce soldering and sent them to OSHPark for the boards and OSHStencil for stainless steel stencils. This was relatively cheap and easy and it significantly reduced assembly time.
2. I refined my designs to reduce to an absolute minimum the through hole parts.
3. I started sending my EAGLE files to MacroFab and was able to get my boards populated and assembled. They are very affordable even when you are only ordering a handful. They differentiate between prototype (1-50) and production (50+) service but your unit price is fairly constant throughout.

To answer your questions:

1. Yes, it can be as easy as cut and paste and that is not a bad place to start. See my carrier board for an example: Electron Carrier Board
2. Yes, take a look at MacroFab but there are likely other options too which I am sure you will get from other replies to this post.

Hope this helps.

Chip

[Vitesze]

Thanks for the reply!

I was thinking of going with Seeedstudio, as I’ve had all my PCBs made there so far. It’s very cheap, and usually arrives here within a week and a half

[chipmc]

@Vitesze,

Yes, I have heard very good things about Seeed as well. Once you start using these services, you will not want to go back to soldering your own boards again. Also, you can integrate a lot onto these boards which will make for a cleaner build. Here is a picture of the board I had made at MacroFab:

[Vitesze]

Gorgeous!

Seeedstudio should accept a Production File + BOM File, with the BOM File including Digikey numbers. All my sensors should be for sale at Digikey, so I should be good

I’ll probably get started with watching some Eagle tutorials tomorrow, and then try to design my PCB The only real issue is the JSN-SR04T sensor I use, of which I can’t find any files anywhere.

[rickkas7]

Yes, you can do it. I haven’t had to build anything in quantities large enough to warrant PCBA but I do bring all of the breakouts onto my own boards using Eagle CAD and OshPark. For things with a lot of tiny pads also OshStencils. I have a cheap reflow oven which works fine, but yes, you don’t want to assemble a lot of boards that way, but great for prototyping and getting the kinks out before you make a pile of them with PCBA.

[hwestbrook]

I’ve done a few runs at different PCBA companies – my favorite to work with is Bittele. Very good results and straightforward to work with. PCBWay has also been great. I’ve worked with Seeed as well, but they are more expensive.

Agreed with @chipmc that you won’t go back to making your own boards after using one of these companies.

You might consider finding an electrical engineer for your larger run of units, if only to review your work. The EE’s I’ve worked with are awesome and for a project with the complexity above, you can probably find someone really good to do the work for $2K or less (~40 hours). I’ve had good experience on Upwork.

One word of caution, though, is that in my experience, you need to budget time and money for at least one small run (4 units or so) to do a verification on your design. There will always be some problem in the custom design.

[RWB]

I’m not sure how easy or much cheaper it would be to try to embed the ultrasonic control boards into the new PCB design. I would embed everything but those boards so they are easy to swap out if one of them go bad.

You should be able to drop a 4 pin header on the PCB so you can push the Ultrasonic control boards into the headers securely. Just one idea, kinda how you’re doing it now by the looks of your picture.

Integrating the 2 different voltage converters should be easy. Just copy the layout of the boards that are working correctly is the first step in the right direction.

Learning Eagle or Kicad from scratch will take some patience for sure. When I started from scratch with PCB design I did the same as you and looked for the best video tutorials that I could find to teach me how to use the software.

At the time the video tutorials for Eagle were not very good and none of them were complete training videos. I ended up learning how to use KiCad because I found a course by Chris Gammel on how to use KiCad so that’s what I know how to use now.

Here is the course that got me started with KiCad :

https://contextualelectronics.com/courses/getting-to-blinky/

Now Sean at Sparkfun has a KiCad series they are doing that is probably the most up to date guide to making PCB’s with Kicad that is out there:

I’ve been playing with KiCad on and off for a few years now and have a handle on it now.

The lastest board I’m working on is complex by my standards, having 5 DC/DC voltage converters, P1, Battery Managment System, Watch Dog circuit, LCD Display, Capacitive Touch input panel, and a circuit for running a variable speed cooling fan. It’s also a double-sided PCB so no way I’m going to be able to build this at home with hundreds of parts with a lot being 0402 in size.

The only way to make the boards is by sending them to a fab. My fab choice here in the USA is Macrofab since they have a nice online upload interface and pricing calculator built into their platform.

KiCad has an excellent online forum if you need help which is a BIG plus if you need help. I got help there yesterday when I was trying to figure out how to merge 2 separate projects into one and they helped me figure it out.

KiCad.info Forums

One thing I have learned is that having a PCB build by a fab is that in low quantities the prices are higher than I was expecting. It’s not until you get into the 100’s of units that I saw pricing that made sense for the couple hundred dollar device I was looking at selling.

[cyclin_al]

If you go with Eagle, I found reading the tutorials on the Adafruit learning site to be good. At least they matched my own learning style well.

I found doing schematics in Eagle was quite straight-forward to figure out. Doing my first PCB layout was not so easy; see my advice below for why.

However, I made the mistake of learning Eagle with my own project. I found that it became overwhelming to deal with learning a PCB design package AND making design decisions for my project at the same time. My advice is to learn the PCB design package using a simple example from start to finish. Once you have been through the process, then tackle your own project.

[Vitesze]

Thanks everyone for the replies, it’s helping a lot! The main reason I was opting for Eagle initially is because I already received a 3-year subscription plan for it a few months back, but since KiCAD is open-source I will consider both.

I will get started on watching some tutorial videos today and over the weekend, and hopefully can get started on some PCB designs soon

[Vitesze]

Did the first 4 tutorial videos so far this afternoon - very informative stuff! Can’t wait to start integrating all the breakout board schematics into one PCB

[RWB]

Yea, I have not watched that particular line of tutorials yet, mainly because I know how to do all I need to do already.

I sure do wish they were available when I was starting from scratch a few years ago though.

Also today Digikey offers part Symbols & Part Footprints in the KiCad format for a lot of the parts they sell now. There is a link to download these parts below the part number if they offer the Symbols & Footprints for that particular part.

Also, a precious resource for Part Symbols & Part Footprints is www.SnapEDA.com they have a database of parts that you can download in KiCad format which can save you ton’s of time since you will not need to create symbols & footprints for the non-standard parts you use in your project.

www.SnapEDA.com also has an Eagle to KiCad converter. So if you find symbols & Footprints avaliable for Eagle but not Kicad you can convert those parts to KiCad format easily.

KiCad will allow you to import Eagle design files also if you find a pre-made layout for Eagle that you want to work with.

Stick with it, and you will be amazed that you can now create complicated custom PCB boards just like you see in all the stuff you buy already. I never thought I would be able to do this stuff myself

[LloydChristmas]

I’m not sure what sensors are on those five breakouts, but if one of them is an analog sensor (particularly a sensitive one) going to an ADC pin it can be tricky to design a pcb that incorporates analog signals with digital ones. Controlling ADC noise is a whole science in of itself. Maybe this doesn’t apply to your design but in case it does it’s something to consider.

[Vitesze]

I do use the ADXL-362 accelerometer, which should be analog? Besides that, I’m using a couple of sensors connected to Digital pins, and two voltage regulators. The way in which I intend to use my device though, the accelerometer readings don’t need to be super-precise, as I just need to be able to detect movement, and tell the difference between the device lying flat-down, and being at an angle more than about 45 degrees.

[LloydChristmas]

http://www.analog.com/media/en/technical-documentation/data-sheets/ADXL362.pdf
It looks like the accelerometer uses SPI communication so it shouldn’t be a problem.