By Ken Kaarvik
Investigate what's coming out of your collection of infrared remote controls. With this program running on your GameBoy Color you should get a good idea of what the modulated signals look like as well as the carrier and it's frequency.
Capture 30 different infrared waveforms (10 each Channel A, Channel B, Fast Channel) and save to cartridge memory.
Capture waveforms on Channel A and Channel B at selectable sample rates from 12.40 ms to 999.4 ms
Capture waveforms on Fast Channel at a fixed rate of 1.907 ms. This Channel is for viewing the carrier and calculating the frequency.
Capture and compare different parts of waveforms by adjusting Trigger Delay and Sample rate
View the first 16 pixels being displayed of each channel (one sample = one pixel) in a magnified view.
Pulse counter - Keeps track of number of rising edges to left of Pulse counter pointer. Counts for Channel A and Channel B start at the value of Trigger delay. Count for Fast Channel always start from zero.
"A" and "B" buttons - Channel A and Channel B. Turn portion of screen blue and wait for an infrared signal. A different portion of the infrared signal can be captured depending on what settings sample rate and trigger delay are set to.
"Start" button - Fast Channel. Turn portion of screen blue and wait for an infrared signal. A different portion of the infrared signal can be captured depending on what the setting trigger delay is set to. The sample rate is fixed at 1.907 ms and is useful for capturing the carrier. The trigger delay works as above - it waits for a selected number of modulated pulses to pass before recording a waveform (it doesn't wait for this number of carrier cycles to pass).
"Left" and "Right" buttons - Move displayed portion of waveform. Each waveform consists of 2048 samples of which 160 can be viewed on screen. The viewing offset indicates what portion of waveform is being displayed. The displayed portion is moved 8 pixels at a time .
"Select" button - Cycles though parameters (Trigger Delay, Memory Slot, and Sample rate) that can be adjusted using "Up" and "Down" buttons. Hold down "Select" button to position display window to start of waveform.
On modulated signals (typ 32-58 kHz), Channel A and Channel B will record a high value for a Sample interval if at any time during the Sample rate an IR signal was present.
On main display, rising and falling edges of waveforms are high (IR present).
When Trigger delays are adjusted, a portion of the screen turns yellow indicating that the Trigger delay is different than that being displayed.
The best Sample rates to capture consumer TV, VCR, Stereo remotes (32-58 kHz) appears to be between 29.56 ms and 201.2 ms
New captures are saved to the currently selected Memory Slot.
Samples rates are not nice even values - easier to program it that way however!
This program requires a Color GameBoy - and a cartridge with at least 8K of RAM for saving waveforms.
Download rom irinvest.zip
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