|2010-03-16 Status Update||| Print ||
|Written by Akiba|
|Tuesday, 16 March 2010|
Greetings everyone. I have some good news and bad news. The bad news is the shop is delayed again. Just when I finished my taxes and thought I was clear to go, I got an email from my antenna supplier that my shipment was delayed due to stock issues. Although its possible to open the shop without antennas, I was hoping to be able to have all the components necessary for a WSN node so that people can order things in one shipment. It's kind of petty, but since its my first shop opening, I wanted it to be fairly complete.
Since the shipment was delayed, I decided that it also gave me a chance to do some last minute product tweaks as well. I had a few people pre-order my boards and got some really good feedback from them. One of the problems was that once people put the MCU and radio boards together, the first thing they do is take it out for a range test. The problem is that the MCU board was originally designed just for development and my assumption was that people would be using it tethered to a power source (ie: USB). Actually, the original concept was for it to be an extensible version of the Atmel Raven USB stick which I found very useful, but horrible to interface circuits to. Because of this design decision, there is no battery holder or circuitry on the MCU boards.
After I realized that people would be using the boards in this way, I re-designed the MCU boards with a battery case and power conditioning hardware to maintain constant voltage as the battery drains. I was going to introduce that board as a version bump later on. But due to the delay, I decided that I would start off with the battery version of the MCU board instead. This means that I have to scrap the original boards. Actually, I’m going try and salvage as much as I can from them and probably donate the rest to Tokyo Hackerspace for microcontroller classes. In my opinion, the battery-based boards reflect the actual usage much better and allow for both development and real-world testing.
The other tweak I’m making to the product line will be that the RF connectors on all my radio boards will be changed from SMA to RP-SMA. The reason is that RP-SMA connectors are prevalent in antennas for the unlicensed bands. The whole RF connector situation is a complete mess with SMA-P, SMA-J, RP-SMA-P, and RP-SMA-J.Don't even get me started on TNC vs RP-TNC connectors.
Most dev boards ship out with SMA connectors since its easier to connect them to test equipment for evaluation purposes. However I noticed that the people I’m talking to that are interested in my platform or are actually using it are not doing test and evaluation but are using them straight out of the box. To get them to work, they’re either needing to buy SMA to RP-SMA adapters or locating a dwindling supply of antennas with SMA connectors on them. Although I’ll be stocking the adapters, I don’t want to force people to buy them just to use the boards. The adapters themselves are quite expensive and I figure people that will need the SMA connectors will be in the minority. Hence, I decided to change all the connectors on my boards to RP-SMA. People that need SMA can use an RP-SMA-P to SMA-J adapter (see what I mean?). If that sounds like gibberish, I'll be stocking those adapters as well so you can just ask me. It’s really painful because you need to desolder all those connectors and re-tune the matching network since the RF path is changing. However that’s the price of an incorrect assumption in my original design decisions.
Sorry about all the delays and am getting a very quick lesson in the trials and tribulations of starting up a hardware manufacturing operation, even on a scale like mine. There is definitely much more to it than meets the eyes to get a product released and in hardware, things take a lot longer than in software. I've also learned that an extraordinary amount of attention to detail is required for both functional and manufacturability requirements. And of course, I realize that feedback is very important.
For those that bought the pre-sale boards (you know who you are), please contact me and we can work out a trade or heavy discount to upgrade you to the modified boards.
As for everyone else, once I get the shop open, I’m going to write a nice, long article on the hits and misses of my decisions and actions leading up to the shop opening. I made some really good decisions and some really bad ones and hopefully other people won’t need to make the same mistakes :)
written by Mariano Alvira, March 16, 2010
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