The Opto Tester

This device allows you to test infrared emitters in your pinball machine. the indicator lamp glows bright blue in teh presense of infrared light.


Assemble the tester to a 9V battery. Under normal lighting conditions, the clear LED on the back side should show a blue glow.

Put the sensor (the dark cylinder) near a playfield lamp. the blue LED will glow significantly brighter.

Fish the cylinder into an opto area so that the end of the cylinder is facing an IR emitter. The blue LED will become very bright as it crosses into the IR beam. If it is awkward to see the LED directly, look for blue light in the area. The LED is VERY bright when it detects IR close to an emitter.

You can also test flipper optoslots. The indicator glow caused by these is very faint, and you will need to test in a fairly dark space.

The detector will detect remote control IR from several feet away, but this is best done in a darkened room.

Here's a video of it working on a Creature VUK.


Background and Technical Information

This is another derivative of the switch matrix opto. It adds an LED and a 9V battery connector to allow you to detect IR light. It is small enough and light enough to go most places there's an opto. When it finds IR, it lights blue. When it is in front of an opto emitter, it is a very bright blue.

The detector will detect a TV remote from about 3 or 4 feet away. With the bias resistor removed, it will easily detect a TV remote from 20 feet, but it is then too sensitive to be useful.

A pinball machine in attract mode emits a lot of IR, so the LED will glow a bit. You can go into test mode and turn off the GI to avoid this effect.


Typical Operating Parameters

Dark current consumption        <1uA        No indicator
Typical current consumption    10 - 50uA   Faint blue indicator
IR illuminated consumption    15mA         Bright blue indicator 

Translation: If you keep it in a dark box, you will never have to disconnect the battery
                  Under normal lighting (example: kitchen fluorescent) the battery will last for hundreds of hours


That said, I recommend disconnecting the battery when not in use.

Here's the tester assembled to a 9V battery. The battery is not included.
Here is a picture showing the front and back of the tester.
A picture of the LED under room lighting. This is the dim glow that you would expect to see most of the time.
And a picture close to a halogen desk lamp. The LED is almost too bright to look at, but my camera has taken care of that.


You'll see a dramatic increase in brightness when the sensor gets close to an IR source.