I have a fair bit of industry experience with Electronics Design, as I'm a design engineer for a company in Australia. However, over the last 5 years I've only really specialised in power supplies, control systems, analogue/digital signal processing, and wired communication (RS-232, RS-485, and CAN).
Before I do any professional work with radio, I wanted to do a little personal project at home. Something like two PCBs, one controller and one relay board which turns on a 240VAC relay or something, so as to remote-control a light or other home appliance - with the communication between them / to them being via bluetooth or via some generic bluetooth application on a phone. That scope is for me to worry about.
As someone who has a lot of experience in board design except radio (Wi-Fi, Bluetooth, and RF in general), I had some brief questions for anyone who is experienced in board design for those applications:
- I have decided to go with the Nordic Semiconductor NRF52810. This was recommended by a colleague, as the Nordic support community is great (a lot of noob questions, with a lot of FAE answers containing example layouts/parts/code for specific cases). Any thoughts on using this as a first timer? As much as I shouldn't be picky, it would be nice to have an integrated transceiver solution such as this so as to reduce the possibility of error.
Assuming my said Micro layout is perfect, I had some sub questions:
- I planned to use a pi-layout (C-L-C) for the tuning circuit, with some rough starting values. I know these need to be empirically tuned, but do they matter a heap if I only plan to want 2-5 meters of range?
- For the antenna, I'm planning on using a SMT one (not a board-copper-track one - keep it simple). I've read that the choice doesn't really matter (so long as it can handle the maximum power you plan to transmit). The main thing is that it is designed for 2.4GHz, and has 50 \$ \Omega \$ impedance. I have chosen the Johanson Tech 2450AT07A0100T. Does this seems okay?
Finally, the trace from the Micro -> Tuning Circuit -> Antenna. As long as this is 50\$\Omega\$ controlled impedance, has via stitching to ground along the edges, and is a reasonably short length, is there anything else I need to worry about?
In terms of firmware, that's for me to worry about. The main thing is getting the hardware right. So my last question would be, is there anything I seemed to have skimmed over/missed? Total noob in this field so just be honest.
Thanks so much. If you have any good resources on PCB Bluetooth design from scratch please feel free to comment links. I have read a lot of resources on different parts (chip choice, antenna tuning, antenna placement and routing), but haven't really found a good one on "the whole picture".