Using a Palm serial link cable with the Dakota single-use camera

By Tyler Bletsch (email: tkbletsc (AT) operamail.com)
14 November 2003

Introduction

The promise of a fair-quality digital camera for $11 is a tempting one. The Dakota single-use presents such an opportunity, but with one caveat: one must "develop" the pictures (i.e. download them) for another $11, and give up the camera in the process. This is sub-optimal situation, but not without solution. T. R. Gipson has found that solution in the form a camera download-and-clear operation that one can perform at home. However, this requires a physical connection to the pins on the unit. One can solder directly to these pins or affix some custom connector, but the ability to connect a plug that fits the original port would be ideal. This article presents such a plug in the form of the Palm M100 "HotSync" cable. In short, one can modify the camera and cable to create an easily connected USB cable that plugs right into the camera.

Requirements

These directions assume a knowledge of T. R. Gipson's original article on interfacing with the camera. In addition, you'll need the following resources:

Approach

There are three things stopping you from hooking that palm cable right into the camera and using it immediately:

  1. The camera port is too small for the connector as-is
  2. One of the required pins (pin 9) on the Palm cable isn't implemented
  3. The Palm connector isn't connected to the USB connector (obviously)

The first problem is probably the hardest: the opening must be expanded by melting/shaving the plastic. The second problem is solved by soldering to the PCB inside the Palm connector itself. The final problem is remedied by simply splicing the Palm cable to the USB cable.


Camera with port enlarged

Palm connector, naked, top

Palm connector, naked, bottom, with wire and cut
See un-cluttered version

Palm connector pin numbering

Procedure

  1. Goal: Enlarge the camera port
    2.
    1. Break/melt off small horizontal bar that is part of back casing using needle-nose or soldering iron.
    2. Carefully melt the grey plastic notches until space is rectangular. Be careful not to punch a hole through the battery casing (like I did).
    3. Continue using trial-and-error until Palm connector fits snugly.
  2. Goal: Connect pin 9 (required) to the line for pin 5 (not required)
    3.

      The pinout requires only pins 6, 8, 9, and 10. The connector only implements pins 1, 5, 6, 7, 8, and 10. Hence, pin 9 on the connector is unconnected, while pin 5 (among others) is unneeded. We will take advantage of this by using pin 5's line for pin 9, and disconnecting pin 5.

    1. Remove rubber shield from Palm connector. Remove the two screws revealed.
    2. Take the PCB out of the two plastic sides.
    3. Solder a connection from the PCB connection for pin 9 to the cord-side connection for pin 5.

      4. Pin 5 is now shorted to pin 9. This is undesired and could have unpredictable (and possibly damaging) results.

    4. Cut into the PCB to sever the line running from the pin 5 cord-side connection to pin 5 itself, making sure not to disturb other lines.
    5. Reconstruct the connector.
  3. Goal: Connect Palm cable to USB connector
    4.
    1. Cut into the Palm cable somewhere along its length. Do the same for the sacrificial USB cable.

      2. Note that there is a button on the connector that appears to bridge a capacitor between two of the lines. As this is obviously not the intent, I left the plastic button-cap out to prevent it from being pushed. You may wish to pursue a more elegant alternative.

    2. Use trial and error and a closed-circuit detector to find which wires go to which pins on both the Palm cable and the USB cable.

      3. If the USB cable is standard, then the USB color codes in the table apply. If the serial cable is the same as mine internally, and you chose pin 5 to be the replacement for pin 9, then the "Palm color" column of the table is also applicable. The pinout is as follows:

      Palm pin numberPalm color
      (if same as mine)      		USB lineUSB color
      (if standard)
      10OrangeGroundBlack
      9 (formerly 5)YellowData -White
      8BrownData +Green
      6Black+5VDCRed
    3. Connect the wires such that the purpose listed under "USB line" connects to the pin listed under "Palm pin number".
    4. Reseal the connector
    5. Test all connections from end to end
    6. Obtain the dumping software for your operating system of choice (Windows, Linux/Unix, or Mac), and enjoy.

Conclusion

With a little stabbing with a soldering iron and some defunct cables, one can have an inexpensive fair-quality digital camera. Best of all, because it's cheap and easily modifiable, it is great for high-risk experiments, automatically triggered snapshops (with a little help from an Atmel AVR), etc. Horrah!

History

My price point for a digital camera was less than $20, so I was waiting for the day when the digital cameras would become affordable to the impoverished student. I read T. R. Gipson's article one day on interfacing with the Dakota single-use camera. I was so enamored with the concept that I bought the camera the next day. I happened to have the a Palm serial connector cable from a defunct Palm M100 (mentioned in the article). I decided to try to use the Palm connector, as my soldering abilities are quite feeble. End result: it works great. Hence, I thought I'd share my procedure for using the Palm connector.