Moving from Development Board to Custom Hardware

Question

Hello, 
 I have developed a prototype that uses the nRF52840 Adafruit Feather Express, a few sensors, and some other components. I am somewhat new to hardware engineering; however, I was able to get some schematics designed and I have a custom PCB that uses the Feather Express. I currently use the Arduino IDE to do development, and I'd like to stay there. 
 Having said that, I am trying to reduce some of my costs in my prototype. Purchasing pre-made dev kits and components is very easy to get prototyping, but when I go to Mouser.com and see the raw components the price difference is fairly significant. For instance, the raw nRF52840 is $7 whereas the Adafruit Express is $25. I have been using my prototype for several weeks, and I've got some interest from other people. What are the next steps to go from dev kits to a more targeted/customized PCB? I do all of the soldering myself; however, I was looking at the raw chip, and I'm not really sure how to solder something like that (maybe the USB Dongle is a better choice). 
 I know this post is long-winded. I've attached a picture of one of my prototypes to get an idea of where I'm at.

RK · Accepted Answer

You aren't likely to be able to solder the raw chip by hand, unless you're very good. The older QFNs were fairly tractable, but the newer chips have completely hidden pads, they're pretty much LGAs. It's possible to do them with a hot air gun if you have lots of practice but it's hard. So you'd probably need at least a homemade reflow oven, there's tons of information out there about how to turn a toaster oven into one. So a better bet may be to buy a module which has the chip and crystal and antenna already on it and has certification, if that matters. You can buy the Rigado one for about $10. However that too has pads underneath, although much more spaced and so you'll still need hot air or an oven, those are a lot easier to do than the raw chips however as the pads are pretty well-spaced. 
 Your next problem is that adafruit has done the work to make the whole thing Arduino compatible, I guess with custom firmware and I don't know what else. So if you want to continue with the Arduino IDE you'll have to work out if that firmware is something you can download and use and put on your own custom board, and whether you can do that legally. Personally I'd run as far away from Arduino as possible but I see you want to stay with it, so you may need to ask Adafruit what they'll make available to you; they tend to be fairly 'share-y'. 
 Good luck - looks like a fun project. Are you intending to go commercial with this or just make it available as a hobby project? If commercial you have some vile licensing fees in your future from the Bluetooth SIG which may ruin your whole day.

Moving from Development Board to Custom Hardware

Top Replies