Sunday, May 22, 2011

I am still here.

I just haven't done anything in a week. Lots of kids stuff, and work. I did order that other bluetooth card, and sold some more on eBay, so maybe I can get another Arduino. Maybe I should save up for a new laptop, my  wife wants a new desktop.

Maybe I am the only one in the world who doesn't respect some certain big time aviation mapping company in the world. I think their maps are cool, but their software stinks. I've been dealing a bit with that all week in my professional life, and it seems I sort of being ostracized. Weird, it is like the airplane manufacturer that owns the mapping company is pulling some serious strings. But, the CEO of our company is kind of pushing them.

Hopefully I get to keep my job. Then I can buy more computers.

Sunday, May 15, 2011

Amazing things happen in 24 Hours

My bluetooth card showed up a couple hours after I wrote the last post. Wow! that cars is smaller than I imagined!

So where to start. Well, the documentation leaves something to be desired. Seed has a Wiki page that has some pointers, including the pinouts of the card. It seems to be quite capable. But, so far I can't get it to work. I don't know if I need to connect more than power and Rx/Tx? It appears it needs to run on 3.3V, and my ArduinoMega has a 3.3V pin, so that seems right. Lots of grounds on the board, so that seems good. I connected reset, but this page made it seem like I didn't need to, so I disconnected it. Back in the day, We used to connect pins 6, 8, and 20 in the DB-25 connectors to get around hardware handshaking, so I connected RTS and CTS, but nothing.

I also had some issues with libraries and installing them. The Zip files come with a sub directory, so I'd install a new library in libraries/foo/foo/ well the apps wouldn't compile. I got pretty frustrated, but moving the libraries up to the proper place (IE libraries/foo) the code would compile.

How about this;, there is a schematic and everything! It is a little confusing, their schematic has a level converter (RS-232) but the pinout shows TTL level. Hmmm... 

I also found this card, for $19 I should buy it, since it'll get me prototyping area too. There seem to be many Arduino to Bluetooth solutions available.

I've got some other things to do, I'll get back to this.

I'll see when I  can get back to this.

Saturday, May 14, 2011

Google is Helping!

This week Google has their developer conference, and they announced the Android Open Accessory Development Kit (AODK). It is based on the Arduino board, and talked USB. Buying from Google is expensive, but hackaday has a user who figured out how to use  any old Arduino to do the same thing. I need to look into this some more, since I am cheap, and have lots of ideas for the Arduino Android connection.

Seed Studio still hasn't devlivered the bluetooth shield I ordered a couple weeks ago. It is giving this vendor a black eye in my view. I probably out to write to them before complaining too much.

Not much progress on this project in the last week. Mostly working on stuff around the house. Floor upstairs, end of school year kind of things.

Write if you have thoughts.

Monday, May 9, 2011


I've been thinking about the display. I briefly looked at the Nokia LCD shields for the Arduino, but have so far dismissed them. I've also looked at the larger monochrome displays available, and similar dismissed them.The Nokia displays, while color are too small (128x128 pixels and about 2.5" square), where the large ones are fine, they only are monochrome.

There is a bunch of information one can encode in a color display, everything from warnings, to dithering edges to allow more data on less screen. I am sure I could, if so motivated, put enough information on one small color display. Connecting multiple of these smaller displays up to a network from the main board is another option, maybe allowing 2-1/4" holes to display analog looking gauges. It would certainly be an option.

Using a larger monochome display could work, and for many years there was the popular VM-1000 display that was monochrome. Alerts could be encoded as blinking or changing presentation, including reverse video. The display can show analog and digital presentations, allowing quick checks for out of tolerance readings, and a longer view of specific readings.

Combining displays, making a comprehensive view will allow quick scans to determine more information. Combining all oil and temp into a single graph would allow noting any issues with the oiling system. A similar display could show CHT's and EGT's allowing quick viewing of current cooling status. The comprehensive display will allow showing more data in a larger color display.

Using direct connected displays would also have the disadvantage of requiring something to be farther from the engine. The display being close to the pilot would need to have all the sensor wires brought forward, where mounting the display and engine monitor near the engine would require the pilot to turn around to read the display. (We are talking a Cozy here, not a Cessna, but something similar to an Osprey II or non-traditional engine mounting would be covered).

I am planning on using an Android device for a display. The Android can receive the Arduino data over bluetooth, and possibly USB. Currently tablets are available for about $150 on up, or if you have an Android phone, it should work without any additional expense.The Android has a robust open development platform, and the tools are mostly open.

Using bluetooth allows the option of connecting to other devices, including full laptops, ipads, and other brand computers. I am not going to work on them, but all others to do it if they desire. This is an open project, read and learn along with me.

Tuesday, May 3, 2011

General Avionics Questions

Today the comment came up:

  Are there any pilots that, if you were designing and buying avionics for a Cozy panel from scratch..GPS/NAV/COM/GS/Intercom that would...price point for the GPS/NAV/COM/GS box could be in the $2-2.5k range

Well, I responded, and then I had some explaining to do. I went rambling on about Software Defined Radios (SDR), and I thought most people don't know what a software defined radio is. It is an amazing item, but so far they are kind of expensive (or not). The SDR is able to listen to multiple conversations at once. There are many ham radio operators that have SDRs on line. There is a WebSDR group, allowing multiple people to listen to radios all over the world. I said that right, one SDR can receive many conversations at once, allowing multiple people to listen to the same radio at the same time, on their own station! You can listen to frequency A I can listen to frequency B and someone else can listen to frequency C, each in their own mode (AM/FM/SSB etc). Also, with this software, you can "see" where the conversations are happening.

SDRs can transmit also. They are just as capable transmitters as receivers. They can operate in many modes, including TV (digital and analog). I think the first one was GnuRadio, and then TAPR got involved.  So far things are mostly aimed at ham radio operators, since like experimental airplane builders, they have more latitude within the rules.

Sounds complicated, right. Well, sometimes software is complicated, but people build fancy interfaces to make it simple. There will still end up being a lot of electronics in an SDR, but they are amazingly flexible. Depending on the design, some can do some amazing things.

Imagine flying along, and the GPS quits, (never happens right? check out, and look at the Grid Display Tool, click on the non-precision approach (NPA) button, all that red, hmm.. GPS isn't good enough to use for approaches), what do you do? Well, you have your SDR VOR receiver listen for a bunch of VORs, all at the same time. The receiver has a morse code decoder built in, and a database of VOR lat/lons. Just using triangulation, this sucker can determine where you are, with a reasonable degree of accuracy. Throw in some DME receiving, an ILS or two, and you should know where you are better than the GPS.

I envision some day, we will have devices we carry in our pockets that will be all SDR. So the smart phone that has become ubiquitous can do lots, but it has many radios, and they can be on a lot, burning batteries. How about the SDR having a smart mode, where the radio knows where you are, and uses the correct frequency in the one transceiver based on location.  Say you want to talk to someone across the room, why waste cell tower, use a different frequency, and talk directly to the person. Say you want to watch TV or listen to the baseball game on an AM radio, the SDR can do that. Need satellite radio, no problem.

As you can see, things are changing in the world of radio. No more random tuning and hoping, no more locking us in to old click click tuning, soon the radios will tune in to what we need.