Thank you! That’s exactly what I was looking for. Sorry I was unclear about which component I meant.
I’m not sure I understand what you mean by
“diode OR’ed” to VIN.
Having just looked at the schematic, It seems to me that having a diode will prevent the LiPo from getting 5V (minus the forward drop of the Schottky) applied directly to it, which would most likely destroy the cell. That is, if Vin (as listed on the board) is actually RAW, as listed on the circuit schematic.
Aside from reverse protection for the cell, I think I am starting to understand what you meant. If UVCC (or VBUS from USB) minus the Schottky drop is greater than the LiPo voltage (minus the Schottky drop), then the USB will be powering the SparkCore. If the reverse is true, then the LiPo will be powering the device. It’s also nice that the LiPo voltage should never be able to reach the USB voltage. That should avoid any issues with the two being very close and switching quickly.
These holes are fairly large. Given that the wavelength for a 2.4GHz emission is nearly 6" and the hole size is (at most) .5", I think there might be some attenuation. Would I be able to use the case itself as an antenna? A core design feature of this project is that there are no external features (such as charging ports or antennae), so having anything sticking out wouldn’t work.
Do you know of any that will work? Also, is this related to material thickness, or another factor I might be able to control? If I understand why these losses occur, it is because currents are induced within the metal that create a magnetic field opposed to the external field, which greatly reduces the transmission of the external field through the metal. We are primarily interested in the field within the coil, so all I need to do is make sure there isn’t a conductive loop pathway within the coil. Now that I think of it, what I am suggesting is an awful lot like laminated cores. I am just reducing the maximum area a conductive pathway can enclose.
Anyway, what do you think? I really appreciate all your feedback so far!