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Stratux with 1.54 Epaper Display and OGN transmit

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TomBric edited this page Sep 28, 2023 · 5 revisions

Another example for a stratux installation with radar display. This time using the smaller 1.54 epaper display. This display is perfectly readable even in bright conditions, but of course is not as large as the 3.7 inch version. But using this installation method you can install it in a 57 mm = 2 1/4 inch instrument hole.

ALL-IN-ONE

List of materials

  • Everything you need for a stratux with OGN transmit capabilities, see here on the main stratux page
    • Stratux 3B+ or Statux pi 4 (1GB is enough), welectron or other suppliers
    • T-Beam, amazon or other suppliers. Use the version with Neo 8M GPS
    • NoElec SDRs, amazon or other suppliers
    • GY 91 sensor (BMP280, MPU 9250), amazon
    • Short USB cable, many types, e.g. amazon
  • Step-Down power converter to connect to 12 or 24 v: LM2596 (lots of suppliers), ebay
  • 1.54 epaper display, waveshare, e.g. supplied by welectron
  • SD card extender to be able to access the SD from the front, e.g. supplied by reichelt
  • Aluminum sheets 0.5 mm thick for the case and a small part Aluminum sheet 1.0 mm for the back of the case. The case has dimension 64 x 64 x 150 mm (There is no need for aircraft grade aluminum, simple AlMg3 works good and is easier to bend)
  • 3D printed front. I suggest ASA material, e.g. 3Djake
  • 3 x micro switches 6x6 mm, length 10mm or 12mm (lots of suppliers, reichelt or ebay)
  • silent cooler fan Noctua NF-A4x10 5V, e.g. available here amazon
  • distance holder (brass) and screws 2.5mm, lots of suppliers, e.g. amazon
  • I used D-SUB 9 connectors for the power connections
  • M3 screws to build the aluminum case and M4 screws to fit the instrument into the airplane
  • M4 rivnuts for a better installation from the front. But this is not necessary, you can also use M4 tapped directly in the front
  • depending on your installation, you additionally need external antennas as well as an external gps receiver, e.g. reichelt
  • small M3 screws for the 3d printed front

3D print files

  • OpenScad (if you want to modify something) source
  • STL-File (for direct printing) source

Hints for building

  • First 3D print the front, consisting of 2 parts.

  • Print the backside of the case.

  • Install and solder cable to the 3 micro-switches in the front.

  • Install the sd card extender in the front and fix it from the back with hot-glue

  • Install the display from the back, put the front part in place and fix everything with small M3 screws

  • Cut the aluminum case consisting of

    • part 1 "main": cut (61+64+61)mm x 160mm from aluminum 0.5 mm. Bend 2 times at 64mm.
    • part 2 "top cover": (65+13+13)mm x 160. Bend so that the inner dimension is 65 mm.

  • put the case together and drill holes at the front and the backside. Tap 3 mm threading into the front and the back.

  • Install M4 rivnuts in the front for the fixing screws of the instrument panel.

  • Install the T-beam on the left side of the case with 5 mm brass holders. Connect the antenna and gps via an ipx-sma cable.

  • Install the LM2596 step down converter also on the left with 5 mm brass holders.

  • Install the fan on the right side using the noise dampeners. Cut opening holes to get enough air out on the right side.

  • Install the raspberry pi 3B or 4 via at least 20 mm long brass holders on the right, just on top of the fan.

  • Install all 4 SMA connectors at the back. Cut holes in the back to get air flow into the case. I additionally recommend to use a small part of aluminum sheet (3.5cm x 3.5cm) for a connection and grounding of all SMA connectors at the back. The holes for the SMA connector are 6 mm. Install this on the inside of the back.

  • Adjust the LM2596 step down converter to an output voltage of 5 V. Do this by connecting the input to some voltage between 8 and 40 V. I use an old laptop power supply with 19 V.

  • Connect all cables. Some hints for the connections:

    • Power connections to raspberry PI 3B: You can solder power cables to the Pi 3B by

      Cable Connection Point on Pi 3
      VCC + 5V PP2 point (near the USB mini power connector)
      GND Solder to large fixing point of network or USB connectors

    • if you use a Pi 4, use the following connection points for power:

      Cable Connection Point on Pi 3
      VCC + 5V TP1 point
      GND Solder to TP7 connection point

    • Connecting the GY-91 Gyro Sensor and Barometric Sensor: Solder the cables on to the GY-91. On the Pi you either have to solder cables to the GPIO pin or the better choice is to connect via crimping of "Dupont" connectors to the GPIO pins

      Connection on GY-91 Connection Point on Pi 3
      VCC +3.3 V PIN #1 at GPIO
      GND PIN #9 at GPIO
      SDA PIN #3 at GPIO
      SLC PIN #5 at GPIO
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