Paul René Jørgensen

As I wrote earlier; The customer support from Infinity Hobby is excellent, and I received my Gaui 330X the same day as I wrote the previous post. Took me 3 hours to finish the build and this is the first video I’ve shoot using the GoPro HD cam and the 330X.

I just wanted to let you know about todays progress. The GPS module landed in the mailbox this morning, but I forced myself not to rush and wire it up to the Spot right away. I know that this GPS module is compatible with the Spot so there was no reason to rush it.

What I was more concerned with was the enable/disable switch and the rudder pass through signal. I started out wiring up the RC receiver to the spot and wrote some lines of code to get the pulse length of a signal connected to one of the Dx pins of the Spot.

    private int getRCPulse() {
        EDemoBoard edb = EDemoBoard.getInstance();
        IInputPin pin = edb.getIOPins()[EDemoBoard.D3];
        return edb.getPulse(pin, true, 30);
    }

These few lines of code should give me the length of the pulse coming in on the D3 pin every 30 ms measured in microseconds. And guess what happened when I connected the battery? It worked!!

Next up was to prototype the rudder servo pass through. I added some more wires to the Spot connecting the servo signal cable to one of the Hx pins and made sure the servo was powered by the RC receiver.

        Servo s = new Servo(EDemoBoard.getInstance().getOutputPins()[EDemoBoard.H1]);
        while(true) {
            int l = getRCPulse();
            s.setValue(l);
            System.out.println(l);
            Utils.sleep(1);
        }

This code reads the rudder RC channel and passes the value on to the connected servo. Amazing as it sounds, but it actually works!

I now have a spot decoding the RC receiver signal and later outputting it to a connected servo, passing it through the spot as if it was not there! This is what is supposed to happen when the autopilot is disabled. When I hit the gear switch on my transmitter the autopilot logics should kick in. But that is another story..

Crazy me have been thinking about this for some time now. Those who know me know that I’m trying to make a part time business taking photographs from the air using RC model aircrafts. I have a dedicated page for some of the videos I’ve been making at http://paulrene.no/index.php/aerial-photography/. I even set up a page for my business at http://settfraluften.no (Norwegian only).

Anyway; During spring this year I got hold of a Sun Spot development kit and I’ve been playing around with it for a while. When writing a program to control servos using the built in accelerometer the idea struck me that this would be a nice platform for an autopilot. I’ve never worked in this field before so this is all new to me and a bit of a challenge. But if I can pull this of it would be a nice project and maybe something that would inspire others to do the same and improve it.

One of the first things I did was to assemble a list of parts:

• Sun Spot - http://www.sunspotworld.com
• Pressure sensor - MPX5100AP pressure sensor 15-115kPa
• GPS module - GPS-module EM-406a
• Headers - Stiftlist 2×10poler rak Au
• Gyro - MKS 380 Aeroplane Gyro

Along with this I need servos, RC receiver, wires and connectors.

The feature list as I see it just now will include:

• Way point navigation using rudder control
• Altitude hold
• Autopilot enable/disable using separate RC channel (landing gear channel)

I’ll continue to write about this as the project evolves. Stay tuned, this will be fun!

I’ve been passionate RC-pilot for the last year and started early on to attach my digital camera to the plane. I do a lot of videos from Bærum and I’ve now collected them on a single page to make them easier to find. And I do have a Aerial Photography license from Nasjonal Sikkerhets Myndighet, the Norwegian authority governing all data gathering from aerial sensors. Heavy stuff, but nice to have if someone makes a fuzz about it.

You’ll find all my videos on the Aerial Photography page. The link is located on the right side of the logo or you may click this link: http://paulrene.no/index.php/aerial-photography/

This is a small tutorial describing how to use a RC gear to trigger a Canon Camera loaded with the CHDK add on firmware. Using CHDK enables you to write scripts that can run triggered by a 4 volt current on the USB port of the camera.

List of parts:

• 1x old servo
• USB mini-B cable
• RC-transmitter
• RC-receiver

To make an remote controlled trigger I started by disassembling an old HXT 9g servo.

Be very careful not to destroy any of the wires. I removed all the gears, but kept the pot wires attached so I could adjust the center point.

I then removed the two green wires and used a multimeter to determine the polarity. Then I connected the wires to a spare USB mini-b connector.

There are 4 types of USB connectors. The Canon cameras using the Mini-B type. The pin descriptions according to Wikipedia are described in this table.

Connect the positive servo motor cable to pin 1 (red wire) and the negative motor cable to pin 4 (ground). You should check and double check your wiring using a multimeter. Attach a receiver and battery to your servo and test that giving you’ll get about 4.2 volts on one side of the stick and -4.2 volts on the other. Remember the correct stick movement to generate the positive voltage. If your transmitter is programmable, remove the stick movement that gives your the negative voltage or be very careful when using remote trigger.

Now it’s time to upload a script to your camera and check if it all work.

@title Remote button
:loop
wait_click 1
is_key k "remote"
if k=1 then shoot
goto "loop"
end

Create a file in /chdk/scripts/ folder of your SD card called remotetest.bas and enabled it in the scripting menu of the camera (after enabling the ALT-menu).

Attach the cables and power up the transmitter, receiver and servo. Hit the shutter button on the camera to start the script and then use the stick on the transmitter to trigger the running of the script.

Congratulations! You now have a non-mechanical way to trigger your CHDK enabled Canon camera.

I’ve been putting this off for too long, and I know a lot of people have been requesting this for a while, so here we go. I’ve split the tutorial in 2 parts. Part one cover finding the correct CHDK build and installing it on your camera, the second part is about scripting and building a remote USB trigger. The CHDK project is a firmware add on for Canon’s Digic II and Digic III cameras unleashing the hidden power in your cheap or medium priced camera such as RAW format, live histograms, Zebra mode, battery indicators and my personal favorite, scripting!

Part 1 - Finding the correct build and install it on your camera

First of all, the modifications we are about to do is not permanent. You may at any time disable or uninstall the CHDK firmware. By removing the write protection on your SD card you disable the auto load of CHDK. And by deleting the CHDK files from the SD card, you totally removes any traces of it. After getting used to CHDK, you’ll hardly want to remove it, but now it’s been said

CHDK’s home page is located at http://chdk.wikia.com/wiki/CHDK and this is where our search for the correct CHDK build starts. Every camera model need a different build of CHDK, because they all are a little different internally. Customizing CHDK for a new camera model is a complex and time consuming task, so I encourage you to show your gratitude by writing about it on their thank you page.

As of today (3. May, 2008) these are the supported (See the CHDK page for an updated list) cameras:

• A450, Fw: 1.00d
• A460, Fw: 1.00d
• A530, Fw: 1.00a
• A540, Fw: 1.00b
• A550, Fw: 1.00c
• A560, Fw: 1.00a
• A570, Fw: 1.00e, 1.01a
• A610, Fw: 1.00e, 1.00f, (1.00d with CHDK version for 1.00e)
• A620, Fw: 1.00f ( 1.00e is not compatible. You must upgrade to 1.00f first (see here))
• A630, Fw: 1.00c
• A640, Fw: 1.00b
• A650 IS, Fw: 1.00d
• A700, Fw: 1.00b
• A710 IS, Fw: 1.00a
• A720 IS, Fw: 1.00c
• S2 IS, Fw: 1.00e, 1.00f, 1.00g, (1.00i with CHDK version for 1.00g)
• S3 IS, Fw: 1.00a
• S5 IS, Fw: 1.01a 1.01b
• G7, Fw: 1.00e, 1.00g, 1.00i, 1.00j
• SD450 (IXUS55), Fw: 1.00b, 1.00c, 1.00d
• SD500 (IXUS700), Fw: 1.01a, 1.01b
• SD630 (IXUS65), Fw: 1.01a
• SD700 (IXUS800), Fw: 1.00b, 1.01b, (1.01a with CHDK version for 1.01b)
• SD800 (IXUS850), Fw: 1.00e, (1.00d with CHDK version for 1.00e)
• SD850 (IXUS950), Fw: 1.00c
• SD870 (IXUS860), Fw: 1.00c
• SD1000 (IXUS70), Fw: 1.01b, 1.02a, (1.01a with CHDK version for 1.01b)
• TX-1, Fw: 1.00g, 1.01b

The version number in green refers to the original firmware version of your camera. You need to now this to be able to find the correct CHDK build for your camera.

Locating the original firmware version of your camera

1. Create a file called ver.req in root directory of your SD card using a card reader and your computer. This could be an empty text file, but remember that the file extension must be .req for this to work
2. Put the card back into the camera and turn on the playback mode (Don’t turn it into rec mode first and then play, playback mode must be the first mode after power on)
3. Press and hold the SET button, then press DISPLAY while keeping both buttons pressed

If this is done correctly you’ll see a text string that looks like Firmware Ver GM1.00E. The “1.00E” is the firmware version you need to remember when downloading the CHDK for your camera. Note: Some cameras even support a file called vers.req that will allow you to even view more information about your camera.

Downloading CHDK

Go to http://chdk.wikia.com/wiki/Downloads and search for your camera. Download the version that matches the firmware version that you found in the last step.

Installing CHDK on your camera

1. Extract the PS.fir and Diskboot.bin files into the root directory of your SD card using your card reader and your computer
2. Put the SD card back into the camera

Enabling / Starting CHDK manually

1. Start the camera in playback mode
2. Press the MENU button
3. Go to the new menu entry called “Firm Update” (probably the last item in the menu list)
4. Select that item and confirm you want to update by selecting “OK”
5. The camera will now reboot and you’ll see CHDK’s splash screen when it boots up again

Auto enabling CHDK every time you turn on your camera

1. Enable CHDK manually as described above
2. Enter ALT mode
3. Press the MENU button to bring up the CHDK menu
4. Enter the “Debug Parameters” item
5. Select “Make Card Bootable”
6. Turn off the camera
7. Take out the SD card and write protect it
8. Put the card back and turn on your camera

CHDK will auto load every time you turn on your camera from now on. You may disable CHDK by turning off the write protection of the SD card.