Friday, December 12, 2014

Bluetooth or WiFi

Ever since I started the engine monitor project, I've had this nagging feeling in the back of my head about using Bluetooth for the engine monitor. Sure there are a lot of things that use Bluetooth for diagnostics and such on a smart phone. I rarely see anything permanently connected except car audio.

Bluetooth's biggest problem for this application comes with the idea of pairing. The only one (sometimes two) device can be paired with a tablet or phone. If you want to listen to audio from the tablet and get engine monitoring inputs to the same tablet, Bluetooth isn't the answer.

I've often thought that WiFi or USB might be a better solution. USB OTG is very common on most Android devices. OTG means the phone or tablet can be a host as well as a client. As a host, the phone can have a USB keyboard and mouse plugged in, and be useful (not portable though). Having the tablet or phone talking to the Arduino could be done for monitoring things, and using a USB hub, probably even charge while displaying engine settings.

USB's biggest drawback for this application is wire. There will need to be about 12 feet of USB cable from the front of the aircraft where the tablet would be to the back of the aircraft where the engine monitor would be (I have a Cozy that is a pusher). Putting a USB hub in the middle of the airplane would give me 2 six foot runs, but it still is inconvenient, and another point of failure.

WiFi, until recently, was a financial challenge. With Aurduino boards costing under $20 for what I want to do, and WiFi shields costing about $40 (sometimes they can be had for $30) it just didn't make sense. I am still trying to come up with a budget device that anyone can put in anything from a $10,000 homebuilt to a $500,000 production aircraft.

Recently a Chinese manufacturer has starting selling $3-5 wifi modules that will talk SPI and will run on the Arduino and other systems. The ESP8266 is available today for about $5. There are tutorialslibraries and sample applications for the Arduino. The module has an onboard processor that people are taking advantage of to make standalone projects, no Arduino required. It could be the thing that makes IoT a reality for many more consumer applications.

The module supports WiFi Direct (P2P) meaning I don't need a WiFi hub in the aircraft. The tablet or phone can talk directly with the module. If there is a hub in the aircraft, then that will work as well. It makes the whole wireless modules in the aircraft more of a reality.

I've ordered one of these modules, it may be a couple weeks before I get it. It will probably be a little while before I integrate it in the engine monitor as well. I'll keep you up to date on my progress.

Tuesday, December 2, 2014

I moved

I know, this blog seemed to go inactive for the past few months. I've been busy, but not specifically working on the engine monitor, but making it easier to work on it. I have a house where my family and I are all together, and it is near the airport, so I can get out to the plane to work on things when I get time. Of course setting up a house can take time, so that is what happened.

I've also upgraded phones. Still Android, I have the OnePlus that I got before they opened up buying to everyone. It seems to be a very nice phone, but I've had it less than a week, so I can't judge things too much. I tried to buy a Note4, but that process was fraught with challenges (some of it moving, some of it carrier store issues). I figure this phone ought to keep me happy for at least a year, and then I can look at the 64bit phones and see what they are like, or if I want one.

The convergence in the phones is really about to the limit. Right now the main features are battery life, camera and display. The displays are all about 1080p-450dpi. (yea, I know a comodore 64 could have 300dpi on a 1 inch screen).  Yes Apple came up with "retna" as the benchmark, but it is all about what you can see and are you happy. Heck I don't really watch movies on my phone, I use the tablet to do that, so do I need 450dpi, probably not. I'd rather have longer battery life on the phone, and a good display on a tablet.

My app has about 200 downloads. I'd say users, but even I am not using it very much right now. I don't know if anyone is using it, I am not seeing any crash reports or anything. I know the code is very robust, but I would think if people were using it, they would get in some state where it would crash once in a while.

The other thing I am working on is expanding the audience of this blog. It is fun writing, I just wish someone would let me know they like my opinions or not. So far I am getting nothing, but I will hopefully add to that. I'll let you know how when things are more firm. Just let me say that there is some traditional media working.

That is probably it for now. Feedback is more than welcome, help me serve you.