Aerial Photography

This project was submitted to Parallax by Mike Shellim of London

Camera mounted over wing, pointing sideways which allows for accurate  handling of the plane.

To make the unit you will need a BASIC Stamp® 2 development kit and some components as listed below. Two versions of the code are available:

Stamp BS2 Cam Interface code v1.1 - without resolution control.
Stamp BS2 Cam Interface code v1.2 - with resolution control.

The interface uses a Stamp BASIC Stamp 2 microcontroller. This comprises a PIC with an on-board PBASIC-code interpreter chip and some RAM for user code. The BASIC Stamp microcontroller is programmed in PBASIC from a PC. There are high level commands for reading/writing square waves, RS232 serial coms, and it runs on 5V. All these factors make it ideal for this kind of project.

In operation, the interface monitors pulses on one receiver channel. When a state change occurs (corresponding to a switch being moved on the transmitter), the interface generates a command string which it outputs to the camera via the built-in RS 232 port. Alternatively the interface can trigger the camera at regular intervals without an RC link.

Graham Woods launching camera-equipped Algebra for the author. (Graham Warren photo)

Cameras Supported:

The unit has been tested with Olympus C400L, D340, and C840L cameras. However, several models of digital cameras use the same Fujitsu chipset and the interface should work with those.

Operating Modes are as Follows:

R/C Mode,Single-shot - by toggling transmitter control from off to on.
R/C Mode,Time lapse - tx control left on. Trigger intervals variable in steps between 10 secs - 1 hr
Standalone Mode - Time lapse only as above.
Configuration is via switches on the unit.

The prototype can be powered by the receiver battery.

Ivanhoe Beacon

Parts List:

BASIC Stamp Development kit
2 x 220 ohm resistors
1 x 22k ohm resistor
8 x 10k ohm resistor (or use suitable SIL package).
1 x red led
1 x green led
Cable for RS232
Plug to fit cam RS232 port (depends on camera model)
Servo cable and plug
Single-sided perforated printed circuit board
8-way DIL switch
Jumper wires (old resistor wires will do).
DIL carrier for BS2
Cable tie
Construction Notes:

I/O pins 0-7 (i.e. BS2 pinouts 5 – 12) are wired identically to a switch and pull-down resistor, only the connections for pin 0 are shown. Note that the wiring could be made a lot simpler - and the package shrunk - by using a SIL package for the pull down resistors connected to I/O pins 0-7 (see picture of Gary Thurmond's unit below). This would remove a lot of the jumper wires. I haven't shown this 'cos I didn't build it like this!

If configurability is not required the board could be shrunk even further by leaving out the switches and associated resistors - the code would have to be edited however.

If using more than four cells, connect the battery +ve to the Regulator Input (pin 24).

I/O Pins:

I/O Pin(s) Function
0-5 TimeoutVal 0 - 127. Pin 0 is LS bit.
All switches OFF = 0, all switches ON=63
6 Multiplier for TimeoutVal (pins 0-5)
ON - timeout = TimeoutVal minutes
OFF - timeout = TimeoutVal x 10 seconds
7 Mode
OFF=R/C
ON=Standalone

Note: the pin number on the BASIC Stamp package = I/O pin + 5

An RS232 cable will need to be made to connect camera to interface. See below. All RS232 signals are from the BASIC Stamp 2 module's perspective.

"If you build one or even use it as a basis for your own design, please share your experiences and perhaps send me some pictures. I'd be most grateful for any comments or suggestions."