So the obvious path to a fast rejection of DW is to buy their ready-to-go eval kit with the K9 antennae. If it fails we are done for an outlay of $600 and a little software. If it works it’s pretty much at end of life unless we can reprogram it to be some sort of base station.
If we buy modules then we have to make some sort of carrier board like you did for TS02a using the DW modules. That’s ugly and a lot of work, but it perhaps has some slightly more lasting utility, and we get to see how well a properly designed antenna operates. I think it will be a while before I have done the BLE part so waiting till June for modules is no big deal – indeed who knows when I will manage to get back to the US and carry on, though I should be able to work quietly in the UK for a while.
Building our own board with a chip and making our own antenna seems like a bridge too far, and there are too many things that have to work on your side of the house before we can test out the basic idea.
I think flexibility to try a whole bunch of fail-as-fast-as-possible experiments is the order of the day. We need an experimental apparatus more than anything else. “Pretty” isn’t important.
I think flexibility to try a whole bunch of fail-as-fast-as-possible experiments is the order of the day. We need an experimental apparatus more than anything else. “Pretty” isn’t important.
I think the first DWBLE (Dewbly?) board should attempt to meet the following goal (in decreasing importance):
- It should above all be easy to debug, so an idiot like me has to be able to attach debugger, and poke it with a scope, when you are not nearby to do it for me;
- It should be at least possible to continuously measure the power and plot a graph against time (well wireless event really). I need to be able to compare different duty-cycles and protocols with some confidence – and do it pretty automatically each time I change a bit of code. It would be upsetting to work on the assumption that something was low-power to find out much later that I had it wrong. Can we count microCoulombes somehow?
- It should be small enough to wrap up with duct tape and velcro to my wrist – even if it needed a D-cell for power 🙂 Have to try and understand the near-body propagation issues. We didn’t really test that with the BeSpoon.
- It should be easy to add warts. If it works well enough we might want to solder on extra off-the-shelf breakout boards with beeper, vibrator, IMU etc.
These are just my ideas, and I know they might be way, way beyond the pale. Tell me what you think about each, and what you think is missing.