How to Use an Old Polaroid Camera as an Ultrasonic Sensor

The sensors in Polaroid cameras can be used in DIY robotics.

Polaroid invented instant cameras — predigital cameras that delivered a printed picture immediately. One of the many innovations of their higher-end cameras was an ultrasonic focusing system, which sent out a sound wave and measured the distance of the subject in the amount of time the sound wave took to bounce back, the same method a bat uses to catch its weight in insects. Robot builders are especially keen on the cameras, as their ultrasonic sensors can be removed and used in robotics for guidance.

Instructions

1. Use a Polaroid camera that is a 6500 model or later, such as the Sun Autofocus 660 or the Impulse AF.

2. Disassemble the camera. Depending on the type of camera you acquire, the ultrasonic sensor can be fairly easy to remove. On the Polaroid 660, for instance, it is that large golden round disc at the front of the camera, right next to the lens. It is only lightly held in place by a couple of tabs.

3. Attach the ultrasonic sensor, or sensors, to the robot. Many robots use multiple sensors, on all sides. The sensors connect to the interface board of the robot, which connects to its computer. The computer then commands the sensors to send out the bat-like ultrasonic (50 kHz) ping. It then measures the distance of an object from the robot by the amount of time the ping takes to bounce back.

Tips & Warnings

• You can acquire the Polaroid sensors directly from the manufacturer, which is now SensComp (senscomp.com). SensComp sells online and through specialty retailers.

• You may want to salvage other parts of the camera as well. Check the Resources for guides to disassembling different parts of different cameras.

References

• Robot Builder's Sourcebook; Gordon McComb

Resources

• University of Oregon: Modifying Sonar Ranging Modules From Late Model Autofocus Cameras