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Themi
by Scheffel Automation
Munich, Germany

Overview
Themi stands for "Thermal Maneuvering Indicator".  It is a unique thermal centering aid.  It consists of a pair of lights that are to be mounted in the sailplane's instrument panel.  The light signals help the pilot find the strongest part of the thermal.  Since a GPS is already included in the unit, the Themi also incorporates a GPS flight recorder that has been approved by the IGC for all flights except world records.


The Operating Principle of THEMI
THEMI contains a precision altimeter, GPS equipment and a powerful micro controller.  It collects data of position and altitude and computes vertical speed, wind velocity and wind direction.  This data is used to generate the position of the center of lift during flight in a thermal. This is called virtual center (VC) of the thermal.  The VC is indicated by lights (LEDs) and updated every second. Using the lights, the pilot can correct his flight path for better lift. The lights are designed to be viewed with only a quick glance or with peripheral vision.  See the table below for an overview of how the lights are used.

Easy to Take Out of the Glider
The Themi is designed to be easy to remove from the glider and take home with you.  The unit arrives with both a "Cockpit Wiring Harness" for permanent mounting in the glider and a separate "IGC Data and Power Cable" for use outside the glider.  The IGC cable can be used to power the Themi and connect it to a PC or Pocket PC.  Since the Cockpit wiring harness contains all the necessary connections in a single connector (12V power, GPS antenna, LED indicator lights, power switch, GPS/PC data cable, etc.), you can remove the Themi from the glider in a few seconds.

Themi Can Communicate with Many Other Instruments
Themi can send NMEA GPS data out the serial port for use by other instruments.  Of course, Themi can operate independently, but if you have a soaring flight computer like an ILEC SN-10, LX Navigation LX1600 or Cambridge L-NAV that requires GPS data input, Themi can provide the necessary GPS position and GPS altitude data.  Cables for connecting Themi to a wide variety of soaring instruments are available in the Cable and Cradle Selection Guide.  Likewise, if you have a Pocket PC or Palm computer running soaring flight software Themi is the only GPS you will need. For a summary of compatible software products see the Soaring Flight Software Comparison.

Data Cable Connections
There are common setups with Themi and other instruments.  Two cables are included with the Themi - a Cockpit Wiring Harness and an IGC Data and Power Cable.  Below are some connection options using both cables.  More cable options are shown in the Cable and Cradle Selection Guide.

• Themi to Pocket PC
  • Themi Cockpit Wiring Harness to Pocket PC - The Pocket PC requires 5V power so a PS-5a is required if the Pocket PC will be used in flight.  If you are using the Pocket PC only for flight log downloads and task declarations while on the ground you will not need the PS-5a.  The PS-5a connects to the Themi Cockpit Wiring Harness through a PXF-1 cable.  A Pocket PC cable such as a an I38C-x could be used to connect the PS-5a to the Pocket PC.  If you don't use the PS-5a the PXF-1 will connect directly to a Pocket PC cable such as the I38C-x.  Below is a graphical overview of the cable connections.
              Themi <-> Cockpit Wiring Harness <-> PXF-1 <-> PS-5a (only necessary if Pocket PC is used in flight) <-> I38C-x (or similar) <-> Pocket PC
  • Themi IGC Data and Power Cable to Pocket PC - The Pocket PC requires 5V power so a PS-5a is required if the Pocket PC will be used in flight.  If you are using the Pocket PC only for flight log downloads and task declarations while on the ground you will not need the PS-5a.  The PS-5a connects directly to the Themi IGC Data and Power Cable.  A Pocket PC cable such as a an I38C-x could be used to connect the PS-5a to the Pocket PC.  If you don't use the PS-5a the Themi IGC Data and Power Cable will connect directly to a Pocket PC cable such as the I38C-x.
              Themi <-> IGC Data and Power Cable <-> PS-5a (only necessary if Pocket PC is used in flight) <-> I38C-x (or similar) <-> Pocket PC
• ILEC SN-10 - Custom Goddard cables are used to connect the SN-10 to the Themi, the instrument panel connector, and (if desired) a Pocket PC. 
  • SN-10 to Themi Cockpit Wiring Harness and ILEC Instrument Panel Connector -  SN10b-Pnl-Themi-1. 
  • SN-10 to Themi Cockpit Wiring Harness, ILEC Instrument Panel Connector and Pocket PC - SN10b-Pnl-PS5a-Themi-1 and a PS-5a power converter.  A Pocket PC cable such as a an I38C-x could be used to connect the PS-5a to the Pocket PC.  If you are using the Pocket PC only for flight log downloads and task declarations while on the ground you will not need the PS-5a.

Using a Pocket PC for Themi Fight Log Transfers and Task Declarations
It is possible to send task declarations to the Themi from a Pocket PC using the TURN-SCH.exe utility.  You can also download flight logs from the Themi to the Pocket PC using the DATA-SCH.exe utility.  That way you don't need to bring a PC to the airport.  A utility called PocketDOS is used to run the Themi utilities on the Pocket PC.  Required data cable connections are described above.

Procedure:

• Install the PocketDOS software on your Pocket PC.  It is available at www.pocketdos.com  
• Create a directory called "Themi" on the Pocket PC.  The directory can be in the Pocket PC's internal memory or on a memory card such as an SD card or CF card.  I recommend that you put the Themi directory in the root directory of the storage card but it would also work to put it in the root of the My Documents directory.  The procedure below assumes the Themi directory is on the Storage Card.
• Copy Themi transfer utilities "TURN-SCH.exe" and "DATA-SCH.exe" into the Themi directory on the Storage Card or the Pocket PC.  The easiest way to copy files to the Pocket PC is to use Microsoft ActiveSync to connect the PC to the Pocket PC and then use Windows Explorer on the PC to copy the files to the Pocket PC.  The Pocket PC is found under "My Computer/Mobile Device/My Pocket PC/Storage Card". 
• Run PocketDOS
• Comm port 1 must be mapped to the serial port on the bottom of the Pocket PC.  To do that:
  • Select "Tools.Settings.Communications.COM 1:" from the PocketDOS menu on the bottom of the screen. 
  • Press the Next button. 
  • Select "COM1: Serial Cable on COM1:" from the drop down list box. 
  • Press the Next button again. 
  • Press the Finish button.  The COM port is now mapped to the connector on the bottom of the Pocket PC.
• PocketDOS sets the "C:" directory as the "Storage Card" by default.
  • If you created the SN10 directory in the My Documents directory on the Pocket PC you will need to change the path for the C: drive in PocketDOS to point to the My Documents directory.  To do that select Tools.Drives.C:" from the PocketDOS menu on the bottom of the screen and follow prompts.
• To change the current directory to the Themi directory type: "cd themi". 
• Connect the required cables between the Themi and Pocket PC.
• Turn on the Themi. 
• Within 30 seconds - Run either the "TURN-SCH.exe" (for task declarations) or "DATA-SCH.exe" (for flight log downloads) utility on the Pocket PC by typing "turn-sch" or "data-sch" (lower case is OK). 

Technical Information
Weight of Themi: 12 oz (340 grams)
Weight of wiring harness: 6 oz (170 grams)
Dimensions: 6 x 3 x 1.75 in (150 x 75 x 45 mm)

IGC Approval Document
http://www.fai.org:81/gliding/gnss/themit3.0.pdf

Manual
Detailed operating instructions are included in the manual: 293_e.pdf

Currency Issues
Since the products below are from Germany, the prices are subject to change with fluctuations in exchange rates.

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Part #	Description	Photo Click on image to view larger version	Price	Lead-time
Themi	Themi Thermal Maneuvering Indicator and GPS flight recorder. Note: This unit does not come with a 12V power supply.  I recommend the Pwr-12V-500mA unit below.  It is required if you want to transfer waypoint files and flight logs to a PC while at home (unless you use a 12V battery).		$1295	In Stock
Pwr-12V-500mA	Power Supply Wall plug 12V power supply.  Input: 110 VAC, Output: 12V, 500 mA, Connector: 2.1 x 5.5 mm DC power plug. Perfect for powering any soaring GPS, flight computer, flight recorder, etc.		$9.95	In Stock