SoundBytes Custom User Manual¶
Overview¶
The SoundBytes Custom allows you to easily add sound to your model railroad, module, diorama, or other display. It is a flexible sound player that plays sounds from a microSD card and supports various modes of operation ranging from ambient background sound, event initiated sound effects, and a special beginning-middle-end mode for repeating effects with lead-in and lead-out sound clips. Up to four inputs can initiate playback and each event can cause a different series of sounds to play. These inputs can come from sensors, switches, various detectors, Arduinos, etc.
Complete with control board, speaker, and microSD card, the SoundBytes Custom is a full turnkey audio solution.
Features¶
- Custom sounds loaded using a microSD card
- Four playback modes: ambient, one-shot, continuous, and beginning-middle-end
- Four inputs with individually assigned sounds
- Playback can be initiated with switches, push buttons, an Arduino, or any device with an open-collector output
- Compatible with TrainSpotter and ATOM detectors
- Comes complete with speaker, control board, and 16GB microSD card
- Powered from 5V to 24V DC
Typical Applications¶
- Ambient background sounds
- Sound effects
- Voice narration
Quick Start Guide¶
Step 1 - Power¶
The SoundBytes Custom is powered from 5V to 24V DC, applied through connector J1 (positive to VIN, negative to GND). Alternatively, the mini USB jack can be used to power the SoundBytes Custom, either from a USB charging block or a laptop/PC.
To power the SoundBytes Custom directly from the DCC bus, a power adapter is available.
Step 2 - Speaker¶
The speaker attaches to connector J6 (SPK OUT) on the board. It can be mounted above or below the layout. When mounting it below, a hole can be bored in the scenery or benchwork and covered, for better sound fidelity. This may involve some experimentation.
Step 3 - Event Input(s)¶
Various input sources can be used to initiate sound playback on the SoundBytes Custom. In all cases, the input should be connected to GND when you want sound to play. This can be done with a switch, a push button, a TrainSpotter or ATOM detector, or many other devices. An Arduino or other electronic module can also be used, but the output should be of an open-collector style output.
Maximum Voltage
Do not apply more than 3.3V to the inputs. The SoundBytes Custom may be damaged by higher voltages.
The SoundBytes Custom has four event inputs. These are IN1, IN2, IN3, and IN4 on the terminal blocks around the perimeter of the board. The G terminals provide a convenient GND location to which the IN terminals can be connected via switches, push buttons, etc.
Additionally, power and GND for powering sensors (like a TrainSpotter or ATOM detector) can be found on the SNS PWR and SNS GND terminal blocks, respectively.
Step 4 - Sound File(s)¶
Add sound files to the microSD card. See the Sound Files section below for details.
Operation¶
After powering up, the blue LED will blink four times to indicate the SoundBytes Custom is ready. However, if no microSD card is inserted, or no valid sound files are found on the card, the blue and orange LEDs will instead blink alternately.
Volume Control¶
The volume has 30 levels and comes preset at level 20. Level 0 is mute. There are ten levels above 20 to amplify custom audio tracks with low gain, but these levels should be used with caution as they may cause distortion.
To change volume, press the VOL UP or VOL DN button. The amber LED will blink briefly in response to pressing the button. When setting volume level 20, the amber LED will blink longer than normal to indicate it is the default level. When at the minimum or maximum volume levels, the amber LED will blink rapidly.
Sound Files¶
Sounds can be loaded using a microSD card. The sound files need to be put in folders, with specific folder names, on the microSD card. See the Modes of Operation section for details.
The sound files must also meet the following requirements:
- WAV file named with .wav extension (e.g. mp3 or other formats will not work)
- 16-bit, mono format
- 8, 16, 32, or 44.1kHz sample rate
Note
The microSD card should be formatted as FAT. Most cards come from the factory pre-formatted, including the card supplied with the SoundBytes Custom, so no additional formatting is required.
Option Files¶
For some modes of operation, additional files (option files) are required to be present on the microSD card to select the mode and/or configure the behavior of the sound player. These option files must have specific, and exact, filenames. The contents of the files, however, does not matter - they can be empty. Details of the specific option files needed can be found in the Modes of Operation section.
Filename Extensions
Windows defaults to hiding filename extensions when viewing files on the microSD card. The ".opt" extension in the option filename must be present and cannot be followed by any other characters. The best way to verify this is by turning off the hiding of filename extensions in Windows Explorer. Do this under Options, select the View tab and then uncheck the box for "Hide extensions for known file types".
Modes of Operation¶
Ambient Mode¶
In Ambient Mode, the SoundBytes Custom will continuously play the sound files in a random order. When any input is connected to GND, the volume will be unmuted allowing the sound to play through the speaker. With no inputs connected to GND, the volume will be muted. Even while muted, the sound files continue to play internally, although no sound is emitted by the speaker. This provides a level of inherent randomization to the sound each time the volume is unmuted.
Continuous Play
If you want the sound to play continuously any time the SoundBytes Custom is powered, then simply connect one of the inputs to the G (GND) terminal with a wire.
To configure Ambient Mode, a folder named ambient should be present in the root directory of the microSD card. The sounds in this folder will be played in a random order.
Whenever a folder named ambient is found on the microSD card and valid files are present within it, Ambient Mode will be selected regardless of any other folders or files present on the card. This means Ambient Mode takes precedence over the other modes of operation below.
Event Mode¶
If the device is not in Ambient Mode, then it defaults to event mode. In event mode, the playback of sounds depends upon the state of the four inputs. Each input can activate a different set of sounds, each with different behaviors as detailed below.
In event mode, folders named event1, event2, event3, and/or event4 should be present on the microSD card. The specific input activated determines the folder, and the sounds contained within, which will be played. For example, when the IN3 input is activated, the sounds from the event3 folder will be played.
Note
Only one event will be detected and acted upon at any time. The sound(s) for the first event detected will play until that event is complete, followed by any other events that are active at that time.
One-Shot Mode¶
In One-Shot Mode, when the input is activated (connected to GND), a randomly selected sound file from the corresponding event folder will be played. Playback will end when the sound file completes playing, regardless of the state of the input. Playback will not repeat automatically, but can be restarted by deactivating the input (disconnecting from GND) and then reactivating it.
Option Files¶
| Option File | Description |
|---|---|
| (none) | No option files should be present for One-Shot Mode |
Continuous Mode¶
When initially activated by connecting the input to GND, Continuous Mode will randomly play a sound file from the corresponding event folder. After playing, if the input is still active (connected to GND), then either the same sound file will be repeated or a newly selected sound file will be played (this behavior is determined by the option files below). Sounds continue repeating indefinitely while the input is connected to GND.
Note
Playback in Continuous Mode is not seamless. There will be a gap between sound files. For true seamless playback, Beginning-Middle-End Mode is a better option.
Option Files¶
| Option File | Description |
|---|---|
| continuous.opt | Must be present to select Continuous Mode. |
| shuffle.opt | (Optional) Determines the behavior when a sound file finishes playing and the input is still active. If this option file is present, then a randomly selected file will be played next. If not present, then the first selected file will be repeated in a loop. |
| level.opt | (Optional) If this option file is present, the volume will be muted with a brief fade out, and playback stopped, when the input is deactivated. Otherwise, playback continuues through the end of the currently playing sound file when the input is deactived. |
Beginning-Middle-End Mode¶
For special use cases, Beginning-Middle-End Mode allows an initial beginning sound to be played, followed by an indefinite series of middle sounds, wrapping up with an end sound. This can be used for things like whistles or the sound of a train approaching, passing, and leaving.
When the input is first activated (connected to GND), the beginning sound is played. If the input is still active at the end of the beginning sounds, then the middle sound(s) will play in a random order. Once the input is deactivated, then the end sound will play. If the input is not active at the end of the beginning sound, then the middle sound(s) will be skipped and the end sound played.
If the sound files all have the same sample rate, then playback in beginning-middle-end mode is seamless. This means transitions between the various sound files happen without any delays.
Specific filenames are required for proper operation. The beginning and end sound files must be named exactly as follows:
- begin.wav: the beginning sound
- end.wav: the end sound
Any other files in the folder will be randomly played for the middle sound(s).
Option Files¶
| Option File | Description |
|---|---|
| bme.opt | Must be present to select Beginning-Middle-End Mode. |
Specifications¶
Input Power: 5 to 24 volts DC
Size (Control Board): 3.75"(L) x 2.25"(W) x 0.5"(H)
Size (Speaker): 1.25"(L) x 1.25"(W) x 1"(H)
Open Source¶
Iowa Scaled Engineering is committed to creating open designs that users are free to build, modify, adapt, improve, and share with others.
The design of the SND-PLAYER hardware is open source hardware, and is made available under the terms of the Creative Commons Attribution-Share Alike v3.0 license. Design files can be found in the ckt-soundplay project on GitHub.
The firmware for the SND-PLAYER is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or any later version. Firmware for the snd-player can be found in the snd-player project on GitHub.