Single-Board Universal Module

I ordered the 0.9.3 board as well (even though I don't have the 0.9.2 boards back yet). They have the same schematics, but I want to see whether the new compressed design can be assembled or not.

I also ordered one of these:
http://www.ebay.com/itm/221503432907

It is HM-12 based, and should support the latest smartphones with BLE as well as traditional devices. We'll see when it gets here.

well, I violate a lot of the recommended restrict areas for the 0402 parts in the compressed layout, so I am not sure whether they'll be ok for pick and place or not. It mostly comes down to cost. I'm sure that there are pcb houses out there that could assemble this board. I'm not sure we'll be able to afford them though.

I do not want to move RF components to the bottom of the board. I also don't want to speculate too much on manufacturability. Once it is actually working, I'll talk to smart-prototyping about it and see what they have to say.

I got my 0.9.2 boards today as well as the peregrine switches. I soldered up the easy side (bottom) but I think I'll wait until tomorrow to take a shot at the top. With any luck we'll soon know if changing out the switches has fixed the issue

Well after a couple hours of nerve-wracking placement, I've gotten the new board assembled. I had one 0402 component tombstone up on me, but I got that resolved and everything else looks ok. However, the board isn't powering up via USB. I don't see the issue as yet, but it seems to be related to the USB connector. I don't get 5V to the board through the USB connector, but if I apply 5v through the PPM connector, I get 3.3V on the board, so there doesn't seem to be any power/ground short. I didn't expose the full JTAG interface on the board, so I'll need to figure soething out to get it up and going.

Nope, it was really as simple as the usb connector not being connected. I think I didn't seat it properly before putting the board in the oven. Fixing it was more of a pain than I expected, but I now have USB working...On to testing

And.....the switch appears to be working!
All 4 RF chips are talking on the SPI bus.
I am seeing a signal passing through the switch now too!
I haven't verified that all 4 legs are working (the code is blindly iterating through the 4 RF chips, changing the switch every 20 seconds or so), but I am definitely seeing an RF signal passing through the switch now.

So I can finally actually make progress on programming and testing.
Happy days.

bluetooth will be optional. It would initially have no functionality for a Deviation equipped radio. It would be required to use the board in a non-deviation equipped radio. In the future I'll likely add bluetooth support even for Deviation transmitters, but that'll likely be far in the future.

As far as selling it goes, I still don't know. My reading of the FCC regulations say that this module is a sub-assembly (and thus only needs to be tested once installed in a radio, and then only if it is sold that way). However, if the option to hook it up to a PC is developed, then the module becomes a stand-alone device and needs to go through licensing. In that case, it would need to come with an antenna and enclosure since FCC regulation would require that the tested antenna be the only one available. I don't think it is even possible to license the module for insertion to a transmitter. Again, the FCC requires testing with the antenna, and I would not be able to supply the final antenna (since the whole point is to reuse the existing Tx antenna)

Since the penalty for selling an unlicensed transmitter is very high, I would not be comfortable selling this in any form to anyone in the US. Thus I could:
a) sell them myself, but only outside the US
b) find someone outside the US who could sell into the US

I'm more likely to do (b), just because it is a hassle to ship internationally, and shipping from the US is very expensive these days. Either way I have no interest in monetizing this, so any profit would not come to me.

Seeed has a storefront that may make this possible (they're in China and following FCC requirements should then fall to the purchaser). However, I'm not sure this board could have sufficient volume to get them to agree (I think they have a minimum expected sale of 500 items to warrant their time). Checked and it is a 100 minimum which may be obtainable

I haven't done a recent analysis, but I think I estimated that these board would need to sell for ~$50 each to make it worthwhile for anyone to sell them.

SadSack manually assembled a board using only a soldering iron but the man is insane I can't even imagine being able to do so. I believe 2 other users here built the 0.9 board, but I don't know what techniques were used. For me to do it, I use a stencil, solder-paste, tweezers, a home-built reflow oven, and a microscope to check my work. It takes me 2-3 hours (several breaks to keep me from going cross-eyed) and a lot of frayed nerves. I would never consider selling hand-assembled units. They also are quite expensive to do this way since you don't get to economies of scale.

I do have a hot-air rework station, and that was my next fix if I couldn't jumper the connector. SadSack is being quite modest. hand-soldering 0402 parts takes some special skill even with the correct equipment. The stencils from oshstencil are very inexpensive and work great by the way. To the US they ship fast too. I'll post more once I've done some more testing.

I wrote a test protocol that repeats a constant signal on a single channel (one any of the modules). I will use my RF Explorer to measure signal strength and compare to a stock board for each protocol. That should give confidence that the RF section has acceptable performance, and that all 4 chips are actually transmitting. After that, the code is basically ready to go, so I'll plug it into a Devo radio and try it out.

I also have the V0.9.3 board coming, maybe as soon as this next weekend. That one has the same circuit but a more compressed layout to support a proper shield. I need to attempt to build one and see how it goes.

I don't know if I mentioned it before, but these little boxes are great for managing SMT parts:
r.ebay.com/x5qfiY

With hundreds of capacitors that all look identical, I would go crazy without them.