2. Breakout every pin you can, you'll thank yourself later. Add test points and plenty of ground pins just in case.
3. Just because you /can/ make it tiny doesn't mean you should - may be tempting to get tiny boards because of the price, but make sure they're useable /solderable/mountable etc.
Seed studio always gets good reviews from the guys I know who do this stuff, probably not quite as cheap as your link but quality seems to be fairly high and consistent.
I used to do a lot of PCB work back in the 80s and we would never have used right angles on tracks then, most of our traces were very curvy lines. Looking at a few modern boards 45o angles seems to be the thing now. I can't remember exactly why.
That's a bloody good point, I vaguely remember being told that once (possibly in first year), but never really thought about it again.
Just done some reading and seems it's actually perfectly fine for digital signals (up to about 2 GPS anyway), but can be pretty devastating for analogue.
I haven't done any multilayer boards, but when I looked at Ant's design I did wonder about interference between the traces running on top of each other. Decided it probably wasn't going to be an issue on that board, however I didn't think at all about capacitance. That may have a much bigger impact. There's a method for calculating the parasitic capacitance in the second link there, might be worth working out what it would be and seeing what impact that would have on the design.
I'm going to try laser etching a pcb (Well, the mask anyway, still needs to be dumped in ferric chloride to remove the copper) tomorrow. No vias or through hole plating but should be good enough for my needs.
that's what i thought... i keep meaning to get around to making a few of these to monitor the house + feed back the data to somewhere.... are you battery powering them? (I'm fairly sure the circuit diagram doesn't tell me this... )
be interested to see how you get on (i'll notice your reply next time i swing by in 2 years time no doubt!)
I've currently already got sensors in various places using Arduinos+nRF24 transceivers+ds18b20 temp sensors. They make up the temperature part of my central heating setup. They're powered by USB supplies. Not made anything that is low-power enough to run long enough off batteries, though that would be the ideal situation, but plugging them in isn't an issue where I've got them located.
Just thought I'd give the ESP8266 modules a go because they're dirt cheap and my wifi network is better than the nRF24 system. Hopefully they'll have better range and reliability.
