Well, it's only been about a month and a half since I took some time off from the software tasks to work on making a stable platform for myself. I have to say that it was a lot tougher than I expected. Actually within that time, I also worked on the webshop beta site, getting the administrative things out of the way (ie: registering a merchant account for credit card handling, choosing and ordering inventory, etc), and working on bringing up the Tokyo Hackerspace now that we've secured a house. Yep, things were mighty busy for the past couple of weeks.

It feels like forever since I touched the stack, and it's weird that I call this an open source software project because it feels like all I've been doing recently is hardware. However I feel like I'm building up a good infrastructure for the project's future. I think the difficult thing about open source embedded projects is getting a stable platform to develop on. It's one of the big differences between a regular open source project where you just develop software for a PC and it adds a lot of complication to things. For wireless sensor networks, it's even more critical because there are so many system constraints that you're dealing with: power management, MCU + resources (RAM/flash, IO, peripherals), radios, and antennas.

I guess I'm probably trying to justify the investment in time and effort for coming up with the hardware, but I do think that it's very important. I figure I'm going to be using the dev platform a lot to take things to the next stage, which is actual implementation. There are a couple of good platforms already available, but they're not exactly great for setting up a wireless sensor network. The platforms that are targeted directly at wireless sensor network development are also on the expensive side so I wouldn't be able to justify spending the money to purchase ten of them. And the worst part is that the platforms are fixed so you just need to take what you get with them. I'm hoping to be able to interchange power supplies, MCUs, radios, and antennas so that I can quickly prototype a platform to suit a specific need. 

But enough about that. I won't know how it goes until I get to actual testing, but I can say that I'll be back to working on software soon. The hardware has already arrived and I assembled the first batch. I did the first group of PCBs by hand because I like to work intimately with new boards. It gives you a good feel for any problems or errors that might have been made. Most people just think about functionality but there are a lot of things that can go wrong when fabbing a PCB. Seemingly simple things like having a pads of a footprint off by a couple of mils could turn into a manufacturing nightmare. Or you often find little things that might have gotten missed during the final check like a misaligned silkscreen, a reference designator that's hidden, and so on. That's why I think it's good to perform initial hand placement so you can get a feel for all the nasties that could turn up and bite you. 

Unfortunately, I won't be able to test the boards immediately because I'm headed to California tomorrow. It's a combination of work for my part-time job and also a chance to visit my parents and sister. I'll be up in Berkeley next week for a couple of days, then shuffling on down to Southern California to care of business. While I'm there, I'm probably going to be placing massive orders with Digikey and other US-based suppliers since the shipping is sooooo much cheaper. Everyone in the US doesn't realize how spoiled they are by not having to deal with international shipping. Also, Digikey won't ship any parts with embedded encryption outside of the US. This of course pertains to most 802.15.4 discrete radios and some MCUs I'm interested in, now that Travis Goodspeed has basically obsoleted an encryption engine integrated onto a radio. If anyone from TI is reading this, please send me a contact to order TI radios in Japan. I can't get them through Digikey and the local distis don't even acknowledge my existence. Apparently, open source projects don't get a lot of respect here :/

Other than that, I have to say that things are going quite well for me recently. I'm surrounded by PCBs, development boards, and really cool parts, hanging out with a really great bunch of geeks, and I'm finding Twitter extremely fascinating. Couldn't ask for more...

Here's a couple of pics of me unboxing the WSN dev platform I designed and assembling the MCU and radio boards. The explanations are in the captions: