| A remote control unit sends messages, using Infra-Red
'light', to video recorders and televisions. Point a remote controller at a light sensor and it may be able to pick up the signal. We tried this with a Video Plus* remote control unit - we pressed the TEST button and recorded the result. The TEST button helps to see if the Video Plus unit is working. |
What we did
We pointed a remote control at a LogIT light sensor and collected data for about a minute.
The results
The graph shows the result - each peak is one of the signals sent from the remote control to the video. You will find some of the following questions easier if you put these results into your data logging software. A
datafile is available a nearby Gallery. Open it in your data logging program.
Looking at the results
The TEST feature on the remote control does this: it sends a signal to switch the video on. It sends other signals to set the channel to zero and then sets it to the correct channel. Next it tells the video to record for several seconds before switching the video off.
- Print out the graph here and put a label on each big peak. Say what each peak or signal is telling the video recorder.
Use your data logging software to find out:
- How long does it take between turning the video on and telling it to record?
- How long does this test run record for?
What you might do
How do they code different remote control commands? Get your data logger working as fast as it can, and see if you can find a pattern in your results.
*Background
Video Plus was a way to programme your video recorder. Like any remote control unit it sends messages, using Infra-Red light to the video recorder. But with Video Plus you key in a special code from the TV listings in the newspaper. The unit turns the code into the times and dates when your TV program begins and ends. When it is time for the TV programme to be recorded, Video Plus sends out Infra-Red signals to the video to tell it to start and stop.
Roger Frost |
