Wildfire Camera Module

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For many years Wildfire carried a TV transmitter module to transmit live video back to the ground during flight. However, in recent years, reasonably priced HD camcorders have become available that offer a significant improvement in video image quality. Therefore, in 2008, a new camera module was constructed for Wildfire. The new module includes a Canon TX1 HD video camera, a Canon SD400 5MPix digital still camera and a GPS radio downlink system.

The GPS downlink system used for Wildfire is the same basic design as was used in Angelfire. Click here for more details. The implementation for Wildfire was simply mounted differently in the nosecone.

Click on any photo below to see a larger image of it.

The Wildfire camera module consists of two main parts. The nosecone section and the payload module just below it. The two parts are attached together with a 1/4" diameter bolt that goes through the top bulkhead on the payload module and through a G10 bulkhead fixed to the bottom of the plastic nosecone. The parachute lanyard attaches around this same 1/4" bolt.

This whole assembly is just under three feet tall and is roughly 5.5 inches in diameter. The whole thing slides into the top of the Wildfire body tube. At apogee it simply "falls out" once Wildfire is hanging on the main parachute. This module connects to its own parachute via the steel cable lanyard seen coming off the left side in this photo.

There are two one-inch diameter holes in the payload module tubing for the two cameras to see out. Another smaller hole is for accessing the camera buttons.

Here the plastic nosecone has been removed. Inside the nosecone is the GPS receiver mounted at the very top. The downlink transmitter is not easy to see in this photo but it too rides inside the nosecone about halfway up. It is mounted on the light green support structure. (There will be a better view of the transmitter a little further down on this same page.)

Here the nosecone and the cover tubing have both been removed. We can now see the two cameras in the lower section.

The upper camera in the lower section is the Canon TX1 HD video camera. The lower camera is the Canon SD400 digital still camera.

For a closer inspection, click on either of these two images to see a very high resolution version of each one.

Front View

Click here for very high res version.

The SD400 digital camera has been modified so that the focus and shutter buttons can be operated by onboard electronics. That's why it has orange Kapton tape all over it holding wires in place. This was necessary because it does not start taking pictures until after the whole module is deployed at apogee.

The TX-1 video camera is powered-up and started by simply pushing buttons on it using a small tool inserted through holes in the body tube. It must be started right before liftoff since it only has a 15 minute record time in HD mode.

Right Side View

Click here for very high res version.

The small translucent plastic cylinder near the middle of the photo is used to hold a Walston transmitter. The Walston serves as insurance to make sure the module can be found in case the GPS downlink system fails. (There was no Walston transmitter actually installed when this photo was taken.)

Back Side View

Click here for very high res version.

A 7.2V NiMH battery pack for the GPS downlink transmitter is held in place with gray duct tape in the upper right section of the module. The power switch is the small black cylinder mounted just above the battery pack. The power switch can be operated by a small screw driver that passes through a hole in the airframe.

Just below the battery pack is a connector that allows an external LCD video monitor to be connected to the camcorder after this module is installed into the airframe. The LCD monitor will display the image seen by the camcorder. This is used to make sure the settings on the camcorder are correct before launch.

Left Side View

Click here for very high res version.

A very sharp observer will spot a large number of two inch diameter steel washers on a bolt right behind the SD400 digital camera. These washers serve as a counter balance weight to make sure the nosecone is still pointed upward while this module is descending on parachute. This achieves two goals. It makes sure the GPS receiver is pointed at the sky and it also places both cameras at a nice angle looking out across the ground below.

Front View with Cover Installed

The cover is flexible phenolic coupler tubing that exactly fits inside the Wildfire airframe body tube. Two large holes allow the cameras to see out. The camcorder looks out a hole in the airframe that matches up with a mirror so that the view is down the side of the airframe. See Wildfire construction page for more details. The digital still camera does not see out through the airframe. It waits to begin taking pictures until the camera module is deployed at apogee. It then takes a full set of photos on the way down while descending on parachute.

Key Components

The Canon TX1 HD camcorder is small but produces excellent video. It measures roughly 3.5"x2.5"x1.2" when the LCD display is folded down flush with the body. It weighs about 8 oz. It records 720p HD video directly to an SD card. One limitation is that it can only record about 15 minutes of HD video in one session. Fortunately, this limitation is manageable since Wildfire flights do not last that long. It does however mean that the camera must be started right before launch.

The Canon SD400 digital still camera was selected simply because it was small and inexpensive yet gives very nice 5Mpix digital pictures. Also because the shutter button design matches the Canon S40 camera used in Starfire and I already knew how to modify it to connect to a controller that can trigger it to take pictures.

The GPS unit is the GPS 18-5Hz from Garmin. It is a small round module that contains both the GPS antenna and the signal processing electronics. It has a standard serial port interface that can send out GPS position fixes five times per second. It also requires a 5 volt power supply. Click here to view the product manual.

The transmitter is a MaxStream 9XTend RF module. These modules are spread spectrum frequency hopping transceivers that have a serial port interface on one end and an antenna connector on the other end. They can transmit up to 1 watt of power when running on a 5 volt power supply. The range is advertised to be as far as 40 miles line of sight with high gain antennas. They are FCC approved in the USA and operate in the 902-928 ISM (Industrial, Scientific & Medical) frequency band. Click here to view the product manual.

More details about the GPS downlink system can be found on the page that describes the Angelfire version. Click here to see it.