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NexGen, Understanding Synchros April 29, 2013

Posted by phoenixcomm in DIY Aircraft Cockpit, Hardware, Software, Synchro.
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There are many types of synchros, Rx, Tx, and Resolvers  But what you have to remember that they are all just motors.
Synchro Diagram As you can see this is really just a 3 phase motor, that is the three (3) Stators, are 120 degrees apart. But you ask what is the Rotor winding for? Well if you look at the picture of your cars Alternator Diagramalternator with out the diodes it kind of does the same thing as the Drive winding on the alternator. So if you took the diodes out of the alternator, and you put a 400 Hz sine wave on the Drive winding, remember you have to spin it, you will get 400 Hz 3 phase power, just what I need for my plane.
Duh Now What?? 😕
So now I have you all thoroughly confused. Right?
In a perfect synchro world you will have a Tx (like on a flap), and the Rx (in the cockpit) which is inside a indicator, both Rotors are driven in parallel  So when the flap is moved the changes on the 3 Stator, windings are impressed from the Tx, to the Rx and if by magic the needle in the indicator moves with the flap.
I will not bore you with the math behind this, but this is a question?

What would happen if you put on the 3 Stators, a 400 Hz  3 phase, that is each one of the phase are 120 degrees apart, sine wave???

But wait, what about the rotor?? Ok that’s the key. Remember what we did with that alternator? We do the same thing here. But we don’t have to spin the synchro, we spin it, or move it electrically!

Digital Resolution of Angular Displacement
Bits n2 Degrees BAM
1 2 180 32768
2 4 90 16384
3 8 45 08192
4 16 22.5 04096
5 32 11.25 02048
6 64 5.625 01024
7 128 2.8125 00512
8 256 1.40625 00256
9 512 0.703125 00128
10 1024 0.3515625 00064
11 2048 0.17578125 00032
12 4096 0.087890625 00016
13 8192 0.043945312 00008
14 16348 0.021972656 00004
15 32768 0.010986328 00002
16 65536 00001

Remember those 3 phases that you put on the Stators well if we call the unshifted signal the reference and you apply it also to the Rotor winding. Your indicator should point to 0. Ok so far?
Now if you phase shift the signal 90 degrees on the Rotor winding your indicator should move to 90 degrees.
Wow this is simple shit, right?
Lets get down to business. You can see a with your eyes about a ½ degree movement. Don’t believe me look at your analog watch’s second hand. 1 second is 1/60 of a circle. So you need about 1/10 of a degree so the indicator will float. So by checking the table you will see you only need 12 bits of resolution. I have also indicated a column for 16 bit BAM, as they are much easier to deal with, than degrees. And I don’t have to use the Trig functions. To understand how to calculate the BAM please look at the link below. One more thing about a BAM it only represents part of a circle. I know I hear the question but we only need 12 bits so why use 16 and through away 4 bits? Well remember the is a computer and it likes things in 8 bit chunks, so getting a 16 bits on a 32 bit embedded CPU is no problem.
Here are two 16 bit functions, I wrote them as that is all you will need:

#define TO_BAMS16(x) (((x)/360.0) * 65536)
#define TO_DEGS16(b) (((b)/65536.0) * 360)

**You will notice that I wrote them as a #define as I let the preprocessor take care of it, rather than making them a formal functions, in that way I can avoid the call and return time. You will also notice the 16 at the end of the name, as I also have 32 bit versions of the functions. The 16 bit version is fine for the instruments  but with the 32 bit version, I can resolve down to a postage stamp size any where in the world!

614L-8 ADF Control Head Hacking, Part 2 January 31, 2013

Posted by phoenixcomm in ADF, Collins 614L-8, DIY Aircraft Cockpit, Flight Simulation, Radio Sub System.
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The Plan Continued.

  • We need to pick a embedded cpu. The requirements are:
    • It must handle all of the GPIO (see part 1 for the I/O Table), or about 20 pins.
    • It needs a USB interface for a data link to talk to the host.
    • It needs to generate the BFO signal.
    • It needs a PWM output to drive the meter.
  • We need to design a interface card. It should have a relay for the Dial Lamps, and a connection to the Panel Lamp Dimmer. It should have a jack to connect the gain potentiometer to the audio system. It should also have an output for the ADF flags, in various instruments.
  • We also need to replace the syncro with static digital encoder. It must be static as when the system powers up there is no guarantee where the dial will be tuned to. Remember this is just a AM radio.
  • Here is a block diagram of the ADF systemADF-System
  • Now we must get the syncro out of the frame. Here is an abbreviated version, I will post some photos when I do the work.
    (TM 11-5826-255-35 page 3-12):

    1. Loosen two Dxus fasteners located on rear cover, and slide the rear cover off the control unit.
    2. Remove three screws and three lock washers securing retaining (rear) plate to frame.
    3. Remove fixed resistor from retaining (rear) plate by removing the screw.
    4. Remove four screws and nuts securing connector to the retaining (rear) plate.
    5. Remove the retaining (rear)plate.
    6. Loosen two setscrews on collar, and remove spur gear from shaft of helical gear.   Note. If the setscrews cannot be reached, the tuning gear train must be disassembled.
    7. Loosen two setscrews on collar, and remove spur gears from the shaft of transmitter syncro.
    8. Remove collar.
    9. Loosen the three screws located around transmitter synchro at the shaft end.
    10. Orient three rim-clinching clamps to permit removal of transmitter synchro and remove the transmitter synchro.
  • Remember re-assembly is just the reverse order. Make sure that you keep all of the screws, etc. in a nice safe place. What I like to do is to put the screws back where they came from.

614L-8 ADF Control Head Hacking, Part 1 January 30, 2013

Posted by phoenixcomm in ADF, Collins 614L-8, DIY Aircraft Cockpit, Flight Simulation, Radio Sub System.
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Collins 614L-8

Collins 614L-8

This is the ADF Control Head that I chose form my project.  It is a Collins 614L-8. they are plentiful on Ebay.

The Analysis    The Unit is tuned via a 400hz syncro transmitter. So it looks like I will have to find a replacement for the syncro.  The Loop Switch in the upper left must be rewired and the switch logic for the Band Selector Switch behind the Tuning Knob seams ok, but that will have to be verified. The Gain Control is just a 5k pot,  and the Function Switch behind it just need some pull-up resistors. It looks like I can drive the Tuning Meter with a PWM signal from the controller.  Also there is a BFO Switch which induces 142.5 Khz signal on top of the audio.

The Plan   Well first I need to score a copy of the maintenance manual they are kind of pricey on Ebay so I dug a little more. In the military the Control Unit is part of AN/ARN-83 and I found pdf copies of TM 11-5826-225-12 and TM 11-5826-225-35 with schematic, part diagrams, etc. Also you can score the operators manual here.

Next we have to identify the goes inta and the goes outas, so here goes:

Connections Map
O Loop Ant, Right Step
O Loop Ant, Right Slew
O Loop Ant, Left Step
O Loop Ant, Left Slew
O Function Switch, ADF
O Function Switch, ANT
O Function Switch, LOOP
O Range Switch, 190 – 400
O Range Switch, 400 – 850
O Range Switch, 850 – 1750
O BFO Switch
 O Gain Control, Bottom
O Gain Control, Top
 O Gain Control, Arm
 I Tuning Meter
 P Dial Lamps
 P Panel Lamps

The Tuning Meter is a dc micro-ammeter requiring 100 micro-amps for full scale deflection.

Stellaris LM4F120 LaunchPad Evaluation Board or the best 13 bucks you ever spent! December 2, 2012

Posted by phoenixcomm in Arduino, DIY Aircraft Cockpit, Flight Simulation, Linux, ps2 keybaord, Software, TI Cortex™-A8 CPU, TI EK-LM4F120XL LaunchPad, TI Stellaris.
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What in the world do you get for $12.99?? LM4F120_LaunchpadYou get this cool 80Mhz 32 bit ARM Cortex M4F Launchpad Board!

So lets take a look at this thing. Well for openers we get both 16/32 bit instruction, and the F stands for Floating Point. It comes with its own on-board USB In-Circuit Debugger. On-board I/O is USB,  CAN, SPI, PWM,  ADC. 16 MHz main xtal oscillator, 33MHz Real-Time Clock xtal. And plenty of memory: 256KB of 40Mhz Flash, 2KB of EEPROM, 24KB SSRAM, an MPU.

TI has provided a great Student Guide and Lab Manual. I went to TI training it cost me $25.00 and I got my kit plus the Ken Tec QVGA TFT display with a resistive touch overlay. 350px-Kentec With this I can model my CDU with out any of my hardware. I also found a nice App Note on using this board as a I/O processor (shows you how to hook up a PS2 keyboard). I looks like I can put my code that’s in my Linux box into the Stellaris board, but at this time im not shure of my code size as yet.  I have only been messing about with this for a month. But I have been busy moving 😦

Now for what do you use for the IDE? Nope we can use Code Composer 5 (Eclipse) and the licence is forever as long as you have the board plugged in. No you can remove it and put in a different one.

Meet the Arduino Killer!! The BeagleBone! November 5, 2012

Posted by phoenixcomm in Arduino, Beagle Board, BeagleBone, DIY Aircraft Cockpit, Flight Simulation, Linux, ps2 keybaord, TI Cortex™-A8 CPU.
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All I can say is: Holly crap Batman

they got it right!

I plugged in the little board (its size is 3.4″ × 2.1)Image It comes out of the box with the Angstrom Linux distro, an RJ45 (Ethernet) and 2 USB ports, one is to connect to your host and the other is for devices, and then just a shit load of I/O! let me explain: two I²C ports, five UARTs,  a SPI interface, a CAN interface, eight PWM ports for motor control etc, eight Analog-to-Digital Converters, and count them 66 general purpose Digital I/O pins!! There are a mess of Shields but here their called Capes, an no your Arduino Shields will not fit.

Gone is the Arduino  bastard kind of C language! Now instead of their smallish library, you can draw on 35+ years of code. No more add-hock programming. It’s not a new paradigm its Linux.  Now I can write and test my code in Eclipse, move it to the bone, recompile / re-target it, or do that on the desktop and run it!

Ok the Bone has a 720Mhz TI Cortex™-A8 CPU, 256Mb DRAM, + Flash. All of this for just under 90 bucks!

Ok like I said before I plugged it into my Linux Mint desktop via the USB port. The board came up within less than 10 seconds. I located it in the finder told it to ‘exit’ thats to change modes on the USB interface,  and then in Chrome and entered in the URL bar and hit enter and I am in the Cloud9 IDE but more about that later.


BTW: My first Challenge is to migrate the PS/2 keyboard code from the Arduino Playground. http://www.arduino.cc/playground/Main/PS2Keyboard to the BeagleBoard.

Arduino Trials and Tribulations, Part 4 (The Linux Platform) July 15, 2012

Posted by phoenixcomm in Arduino, DIY Aircraft Cockpit, Flight Simulation, Linux, Mint 12, Software.
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Well now that I am using Linux Mint 12 with a Cinnamon Desktop for my development with Eclipse (Juno) for my C programming environment. I wanted to make my work easier, so first thing I did was to put my lpr icon on my Desktop…  unfortunately there was nothing in the menu tools. So with a little digging, I found a cool solution so from a terminal, you might want to sudo into shell (sh):   gnome-desktop-item-edit ~/Desktop/ –create-new
Which brings up the Create Launcher tool.  Now edit the tool to as shown, press ok, and you get a new icon on your desktop, that looks like a spring. So right click on it and bring up the property dialog and change you icon.  Now you can drag any file from you desktop filer and drop it on you printer and presto it prints!!

Ok now on to more fun… Well I’m going to move my arduino tools to this box now..
First thing when you try to configure your arduino’s serial port my box only gave me /dev/ttyS0 but we need a serial usb port…. so you need to make sure your that you arduino is unpluged, and run lsusb from your terminal, and you get this:
Bus 005 Device 006: ID 413c:2010 Dell Computer Corp. Keyboard
Bus 005 Device 007: ID 413c:3200 Dell Computer Corp. Mouse
now plug in the arduino and run it again.
Bus 005 Device 006: ID 413c:2010 Dell Computer Corp. Keyboard
Bus 005 Device 007: ID 413c:3200 Dell Computer Corp. Mouse
Bus 003 Device 004: ID 0403:6001 Future Technology Devices International, Ltd FT232 USB-Serial (UART) IC
$sudo modprobe usbserial vendor=0x403 product=0x6001
now when you go to the arduino console you can now select /dev/ttyUSB0

One note: That is only for that jack. If you want to map the other USB jacks just repeat the steps.

ARINC 410 Interface subsystem February 21, 2012

Posted by phoenixcomm in Arduino, ARINC 410, Audio, DIY Aircraft Cockpit, Ethernet, Flight Simulation, G-4390, Gables Engineering, Linux, Radio Sub System, Semiconductors, Software.
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Well it’s about time I posted this interface. I’m not going to show you the whole thing because it goes on for pages and pages. Instead I’m going walk you through one channel in and one channel out.  I’m going to assume that you have a older radio head you know the ones with out the fancy LED displays.  Most (here I go assuming again) use the ARINC 410 interface which is a 2 of 5 code. I described it here in an older blog.


Gables G-3717 Dual Nav Head

Nav Pinout

The Analysis: Well the first thing we found out about ARINC 410 that the signals are low active which means they must be ‘pulled up’  if the radio head does not have pull up resistors installed. As you see from the NAV-1 table we need the following information:

Signal Name ARINC410
Whole MC TENS A, B, E
Whole MC UNITS A, B, C, D, E
DME Indicator 2
ILS Energize

The Plan and a little more Analysis:  I need to get the 4 connectors for the Gables G-4390 (five heads in one panel).   So the one connector is a PTO2A-22-55P so I need my connector guy to give me the mate to this number. It looks like I only have to worry about the fields labeled DME and that a max of 5 bits. So I’m just going to throw away the other 3 bits. There is no off the shelf  2 0f 5  to ASCII decoder, so lets not worry well do that in the driver..

I picked a Arduino  Duemilanove to run the driver and talk to the flight simulator. It only has 14 digital I/O, so could use the Mega 2560 as it has a bunch of digital I/O.

The Plan:  Ok. So we have to talk to the different heads in the plane. And you could have a bunch. So we need a protocol to talk bi-directional to the heads.. here we go.

  1. Write to the interface the head & channel you want to talk to.
  2. Read the response from the head.

Bi-directional communication must use two ports one out and one in.. but its easy to combine them and use tri-state drivers.  First I want to use the 74LS125 or 126. This is an quad package, with each of the buffers having separate controls.   So I can get away with 8 bits..  first since the max we need is to count 0 – 5 thats 3 bits. So lets use the first 3, that give us 5 more to select a max of 32 heads. So lets take a pair of 74LS138 3 to 8 decoder one of them has to be hooked up to the D0, D1, D3 to decode which of the words you want A to E. The second 138 is hooked up to the D4, D5, D6 this will give us 8 radios, really 7, because I’m going to use 0 for power status & LED controls..  Next you have to AND the Radio + Chanel to drive the 5 74LS125 Tri-State Control signals..   So if you use my signals you end up with this: EN_Chan1 + EN_Radio1 = EN_R1Ch1.

The Software:  Ok here goes I’m not going to write the code.. but here is what you need to do.

  1. Initialize the registers.. #int radio = 0; int channel = 0; odd = 0; max_radio = (you radio count + 1(status)); freq [radio][chan]; freq2[radio][chan];
  2. Start Odd / Even loop.. #for(odd = 0; odd < 2; odd++)
  3. Start Radio loop.. # for(radio = 0; channel < max_radio;  radio++)
  4. Start Channel loop.. # for(channel = 0; channel < 5; channel++)
  5. write to the control register with radio, channel.
  6. read the control register and store the results..
  7. if ( odd = 0){ freq[radio][chan] = result from reg}
  8.  if (odd = 1){ freq2[radio][chan] = result from reg}
  9. if (odd > 1) write ERROR.
  10. End of Channel Loop
  11. End of Radio Loop
  12. if(odd = 1){  now check for changes.. you want to do this with some loops..
  13. if( freq[radio][chan] != freq2[radio][chan])  its changed.. now send to the simulator..
  14. odd = 0;}
  15. End of Odd /Even loop

FINS & FYI:  You will need a bunch of the 125’s and lots of pull up resistors. Just for doing my Gables G-4390 with out any more radios lets do some math.. 5 heads * 5 channels per * 5 bits = 5 cubed or 125 buffers (32 packages)  & 125 resistors this is not including status or light drivers..  I wire wrap (power tools), but that a lot of buffers. I am working on putting the whole thing into a Xilinx part. This is a product that I am going sell at Flite-Tronics.com. This still leaves the problem with audio, or driving other indicators, like ILS flags, etc.   If you attempt this I really recommend that you check out Avnet they have the best prices for semiconductors period.

I wish to thank Gables Engineering for the pin-outs and outline dimensions.

Arduino Trials and Tribulations, Part 3 May 4, 2011

Posted by phoenixcomm in Arduino, DIY Aircraft Cockpit, Flight Simulation, Linux, ps2 keybaord, Software.
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It’s Alive, and how I got there!    I made my share of nubie mistakes. There where three right off the bat: First make sure that your serial monitor is the same speed as your program; Two and a big one, make sure you check under Tools->board->(pick your board), and lastly Tools->Serial Port->COM3.  It seems that my keyboard drvier sends out some ASCII (thats good), and some scan codes (thats bad). It looks like the ps2 keyboard driver is sanitizing my out puts for me, so I’m ahead of the game.

Key Press HEX Key Press HEX
0 30 NL 77
1 31 / E0,2F,E0
2 32 * 7C
3 33 7B
4 34 + 79
5 35 ENT E0,D,E0
6 36 DEL 71
7 37
8 38
9 39

Remember I only need to generate 0 through 9, KEYBOARD, TARGET, CLEAR, and ENTER. I like to to take the easy way so I will use: 0 through 9, *, -, +, and DEL keys, that way I don’t have to mess with the scan codes, in my program.

Now I have to hack a ps2 keyboard, to remove the keyboard controller, ps2 cable, and the thin plastic sheets with the keyboard layout you will need them, and put the shell, etc into the garbage.

Arduino Trials and Tribulations, Part 2 May 1, 2011

Posted by phoenixcomm in Arduino, DIY Aircraft Cockpit, Flight Simulation, Linux, ps2 keybaord, Software.
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Well lets get the ps2 keyboard interfaced first.  I’m going to use one of unmodified prototype shields they cost me $16.74 including shipping, oh well. first thing is to scrounge a ps2 female connector, luckily I had a damaged ps2 extender cable with the end that I needed.

Arduino Keyboard Cable Color
5+ Vcc Orange
Ground GND Red
DIO3 CLK Yellow

The first thing I need to figure out how to hook it up. While looking around I found a interface and some code at Practical Arduino I really cant use much of his software as I only have 14 keys, but want to use a full ps2 for testing, I plan on using a keyboard encoder from a ps2 keyboard that I took apart.  Now I will solder the female end of the cable to the shield.

Arduino Trials and Tribulations, Part 1 April 30, 2011

Posted by phoenixcomm in 16 Segment driver, Arduino, DIY Aircraft Cockpit, Flight Simulation, Linux, ps2 keybaord, Software.
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Well I finally got my Arduino Duemilanove and prototype shields, there should be a Ethernet shield, and a LCD shield on its way. I wanted to try and use it on my Navigation Computer Display. To my horror I noticed that you could not stack on top of the prototype shield!

This really stinks I picked them up on ebay. I am going to have to modify the shields, grrr. I found the stacking headers at Adafruit for $1.50 per set.  Not bad.

The Analysis    I need to light four 16 segment lamps and thirteen 7 segment lamps, plus two lamps which will be bi-color leds. So thats lots of wire. My choice  of 16 segment display decoders are far and few between. The first one I looked at was an intersil ICM7243 interfaces with most microprocessors right on its memory bus. but can only handle 8 characters. So I would need two of them plus more glue to handle the last 7 segment display and the two lamps.  The next victims are the Maxim Max6954 with 4 wire interface, or the Max6955 with I2C interface. Other wise they both share the same specifications: They will drive up to 16 displays with mix of 7, 14, or 16 segments. It also has five GPIO pins that can be configured as a keyboard with up to 32 keys with n-key rollover, and built in debounce. The only down side is that they have eighteen  registers to configure the part.  I also need to interface the 2 rotary switches, and well as both thumb wheel switches.  I want to use a ps2 keyboard for testing the display system.

The Plan: Testing    I just go in two of the Max6955AAX+ in 36 pin SSOP package, and my eyes are to old, so I found Proto Advantage not only do they have a great price for the adapters plus they will mount the parts for me. In the meantime I happen to have a Max6954 in a 40 pin PDIP package. I will put it on a breadboard and wire it with a few displays and try to figure out the driver that I will need. – later

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