Monday, May 19, 2014

Doing The Annual Inspection

The weather is getting nice, and I am wanting to work on the plane again. It should be put in condition to fly, and that requires an annual condition inspection. My airplane, being an experimental, and built by me mostly, I have the ability to do my own conditional inspection and sign it off. It hasn't flown for almost 3 years, so I haven't done a complete conditional inspection for some of those years. This one is going to be thorough, I am in no hurry to actually fly.

I've got everything opened up. There are items that need repair (IE drip rail in the front that I broke while storing a box inside the plane), and other things that need a good looking at. I am changing the oil, and sent a sample off to a lab for analysis, to be sure the last couple years of dis-use hasn't done significant damage to the engine. The lab will test the oil for elevated levels of metals that may be early signs of engine damage.

I am looking at the firewall extensively for the engine monitor, and where to attach the monitoring computer.  Most of the smaller wires between the engine and the firewall are for sensors. The wires around the oil filter are oil temperature and pressure sensors. The silvery wires are EGT/CHT thermocouple wires. Under the engine are the fuel pressure wires.  There are the ammeter wires on either side of the shunt (that is a bit of old fashioned technology).

In the annual inspection, I found the ammeter light is burned out. This light is only needed for night flying, since I can see the instruments during the day. Each engine instrument has it's own light bulb, so I am 1/6th of the way through needing to replace them all. It'll be good to replace all the engine instruments with a smart box to monitor all this, as well as display current state.

I've started on the bluetooth code. That is a bigger challenge than I thought, mostly because the Android emulator doesn't support bluetooth. I need to keep my phone plugged in and use that for the tester. It isn't bad, but the phone has lots going on, so the log files scroll fast (and this is my only phone right now.

Soon the annual will be done, and hopefully about that time, I'll be ready to put my arduino in the plane, and start testing some of this. In the mean time, I've ordered another arduino, a mega 256. It seemed I ordered that the same day the arduino zero came out. Why am I messing with 8 bit micros when 32 bitters are about the same price? I don't know, comfort maybe, or maybe it is all I need, the 32bits may not get me anything. (The zero only has the same number of IO pins as an uno, so there isn't a big win yet, some day there may be a mega zero, until then, I'll keep using the mega).

Tuesday, May 13, 2014

More Engine Monitor Updates

This will be kind of a quick post, but the gist of it is, I've been busy. In between getting a new version of my other app out, and explaining the technology behind these gauges on my other blog, I haven't been watching a lot of TV or hanging out in bars.

The new gauges have options that work, and the interface and abstract implementation make these very flexible. Looking at all the gauges, they mostly have the same call, the size differences are sort of hard coded.

In the picture above, you will see round and bar gauges, mostly the same as before. The new changes are the round gauges can go in either direction, be 270 degree, or 180 degree (any sweep angle should work) There is one CircleGauge class that actually draws them all! The CircleGauge class is extended by things like the Ammeter class, or the Volts Meter class.

The gauges have options for clockwise/counter-clockwise, ticks, and various color options (I haven't been setting the color options, these are the  default values. The gauges can have a rotated start angle, and display the title and value in the center of the gauge.

The gauges all get their values from an EngineValues class, that can be set at any time. The next steps will be to put in the bluetooth reading code that will allow me to connect the Arduino to the engine and start measuring values.

What-cha think? Am I heading in the right direction?