Operation Mode #2 - Keypad
The Kaypad Operation Mode uses the Keypad input for trigger. On the
3X4 keypad there are 10 digit keys (0 ~ 9), an ENTER key (may be
alternatively labelled with a check sign or a # sign), and a STOP key
(may be alternatively labelled with a * sign).
To play a file, enter its file number followed by the ENTER key. Leading
zeroes in the file number may be omitted. For example, for file 005 you
may enter 005, 05 or 5. If the file exists, it will start as soon as the
ENTER kay is released. If the file does not exist then the system will go
back to the idle state.
If the ENTER key is not pressed within 5 seconds after the last digit key
is pressed, the entry will be lost.
The system can be configured to either interruptible or non-interrupt-
ible. For an interruptible system a new trigger can interrupt the current
playback, while a non-interruptible system is the opposite.
System Configuration
The system can be configured with a plain text file named MODE.txt
containing one of the following 3-letter codes. If MODE.txt is either
missing or contains invalid data then the system will not work properly.
KNB
System is non-interruptible.
KIB
System is interruptible.
Audio File Naming
The name of an audio file must start with the file number which is a
unique, 3-digit number, and the rest of the filename does not matter.
For example, 008_abc.mp3 is a valid filename while 8_abc.mp3 is not.
File numbering does not need to be consecutive. Number 000 is re-
served by the system and should not be used.
Keypad Wiring Diagram
Keypad must conform to the following wiring diagram in order to be
compatible. The leftmost pin on the keypad connector is pin 1. Back-
light (LED+ and LED-) is optional.
EM21D User’s Manual
Page 3 of 4
Operation Mode # 3 - Timer
The Timer Operation Mode uses the internal timer for automatic trig-
ger. You may skip this section if you are using another operation mode.
The Timer Operation Mode enables the sytem to automatically play a
group of files with a pre-configured delay in between. Up to 10 groups
numbered from #0 to #9 are supported. If only one group is needed,
use the default group #0 so that no group selection is necessary.
System Configuration
The system must be configured with a plain text file named MODE.txt
containing 3 characters:
T??
Here ?? is a two digit number specifying the delay time in minutes. For
example, T08 sets the delay time to 8 minutes so the system will auto-
matically play the next file 8 minutes after the current one is finished.
Audio File Naming
The name of an audio file must start with the file number which is a
unique, 3-digit number, and the rest of the filename does not matter.
For example, 008_abc.mp3 is a valid filename while 8_abc.mp3 is not.
Group #0 uses files 001~099, group #1 uses files 101~199, and etc.
These files are played sequentially, one file per trigger. After the last
file of the group is played, the next trigger will restart the sequence
and play the first file of the group.
File numbering within a group must be consecutive, or the ones after a
break will not be used. For example, if 005 is missing then 004 is con-
sidered the last file of group #0. Files 006 and up, even if they exist on
the memory card, will not be used.
Group Selection
Group selection can only be done via a keypad. The selection will be
memorized by the system even during power outages.
To make/change the selection, connect a compatible keypad to the
KEYPAD port and press the group number key (e.g. 2 for group #2)
followed by the ENTER (or #) key. Afterwards the keypad may stay
connected or be removed.
Group selection must be done when the power is on, and it can be
done for as many times as needed.
Group selection cannot be done when the system is playing audio,
including the background music if applicable.
The system will automatically reset to group #0 if an invalid group is
selected. A group is invalid if its first audio file is missing. For example,
group 7 is invalid if file 701 is missing.
Notes
Although the Timer Operation Mode does not require manual trigger to
play files, the system, when idle, will accept manual trigger via the TRG
input. A momentary contact closure between TRG and GND is all that’s
needed to play the next file (non-interruptible). When the file is finished,
the internal timer resets and restarts.
