Paja

TV Remote controller use a infrared LED to send commands but anything hot glows infrared which means a infrared detect any thing hot. However, the infrared sensor for the TV remote controller only detects if the infrared flash with 38KHz.

This feature can be used in a object detection. Put both a infrared LED and infrared Sensor next each other. When the object come over the sensor, it reflect infrared light from the LED and the sensor detects the infrared light.

schematic plan

PBasic Code

where to buy

It is very difficult to display a moving text on a matrix LED. You have to give 64 commans (8 x 8 matrix LED) in every milisecond but a MAX7219 makes the same result in a few commands.

video

schematic plan

PBasic Code

MAX7219 Datasheet

where to buy

other matrix LEDs