Introduction: Homemade Soundboard

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The goal of this Instructable is to create a reprogrammable soundboard in a compact portable housing and power source. To achieve this, a prebuilt sound board controller from Adafruit is used that can receive audio files from a computer running windows and output stored data via a speaker with the addition of a LM386 amplifier.

Attachments

Supplies

Casing Supplies

Soundboard Supplies

Step 1: Soldering and Testing the Adafruit Audio Effects Sound Board

To begin construction, the header pins on the Adafruit Audio Effects Board were needed to be soldered onto the board as seen in the figure to the top left. To ensure that the header pins were correctly soldered, the 500mAh Li-ion rechargeable batter was connected to the board and to make sure the board is working properly a green LED should be powered on as shown in the figure to the top right.

Step 2: Installing Sound Board Onto a Breadboard With a Low Pass Filter

To connect the sound board onto a breadboard(protoboard), start by placing the ground wires using the datasheet as a guide and connect the opposite ground lines to form a common ground for the system (top left figure). Next in order to prevent any distortion and to provide a clean signal from the board, a low pass filter was built using 2 12k ohm resistors and a 680 pF capacitor which is hooked up to a 10k Ohm potentiometer that will be used to adjust the volume of the speaker (as shown in the top right figure).

Step 3: LM386 Amplifier Circuit

Since the output power of the Adafruit Audio Effects Sound Board is not adequate to play a loud enough sound to the 8Ohm speaker, an amplifier was constructed (top left figure) using a LM386 to increase the volume of the output received from the sound board. Following the specifications of the LM386 from the datasheet, the amplifier was needed to be tuned to an appropriate gain level using a 470uF and 100nF capacitor. To connect the Adafruit Audio Effects Sound Board to the amplifier, the low-pass filter built previously was connected to the amplifier circuit where the output pin of the potentiometer was connected to pin 3 of the LM386 (see data sheet for more information) and the 680pF capacitor of the low-pass filter was connected to the positive terminal of the 470uF capacitor using a jumper wire (as seen in the top right figure).

Step 4: Powering the Amplifier

With the Adafruit Audio Effects Sound Board having its own 5V output pin (seen above where the black wire begins next to the sound board). To provide power the amplifier, the 5V output bin on the board is connected to the power in pin on the LM386 amplifier circuit (Pin 6; see datasheet).

Step 5: Soldering Wires to the Speaker and Pushbuttons

With the speaker and pushbuttons coming without any pre-soldered wires, the distance the wires needed to travel was measured (needed to reach the top of the casing to the protoboard channel) and was cut as needed using wire cutters. Next to assure proper connection, the wires should be stripped and soldered appropriately to the speaker and pushbuttons for them to be ready to be connected to the breadboard.

Step 6: Connecting the Speaker to the Breadboard

To connect the speaker to the protoboard, all that is needed is to connect the positive lead (red wire) to the output of the amplifier (which is connected to the 470uF capacitor) and the ground lead (negative wire) to the mutual ground of the soundboard.

Step 7: Finalizing the Sound Board

The final step needed to have a working sound board is to connect the 500mAh Li-ion rechargeable battery to the Adafruit soundboard which will make the board powered completely wirelessly. With the sound board constructed, we're ready to upload some sound files to the board itself and construct a housing to keep the protoboard in place.

Step 8: Building the Housing

The next major component is to construct a case that can be used to house the built sound board. Although various sizes and materials can be used for the housing, the case constructed in this project used a 2' by 4' piece of plywood to build a 12" by 12" case with the side walls being 4" tall. To begin, the plywood was measured and marked according to the specification using a straightedge to draw and connect the lines (shown above) as needed to begin sawing.

Step 9: Sawing and Sanding the Housing

With the plywood marked according to the expected specifications (as shown in the top left figure), using the help of others and the proper safety wear, all marked parts of the plywood were sawed off using a circular saw having two times the thickness of the side of the plywood (in this case the plywood being 1/2" thick and the circular saw having a reach of 1"). In order to prevent having a harsh surface, the plywood was lightly sanded on each cut edge to remove any outstanding pieces of wood that can cause a splitter when handling the housing.

Step 10: Nailing Together the Plywood Housing.

With the necessary parts cut and sanded, the housing is ready to be put together. To begin, the two short sides were nailed in using a hammer onto the ends of the long sided pieces (shown in the top left figure). After the three sides have been nailed together (1 long and 2 short), they were clamped together onto the bottom piece to make sure all edges are squared together, then nailed on all three sides to the bottom of the housing.

Step 11: Adding the Top to the Housing

Before drilling holes for the pushbuttons being used, measure the thread diameter of the button and outside diameter of the button’s nut. In this case, the button holes needed to be between .616” and .750” in diameter. Next, mark on top of the board where you want your buttons to be placed, predrill with 1/8” drill bit, then use a step bit to drill a hole to the desired size. Make sure to use a button to check the size of the first hole you drill before you begin drilling more. To connect the top piece to the rest of the housing, a hinge was centered on the inside of the back side and screwed into the back wall making the inside of the housing able to be accessed in case the circuitry needs to be troubleshooted or adjusted.

Step 12: Inserting the Sound Board Into the Housing

For charging access, create a cutout large enough to fit the micro-USB housing and drill a 1.25" hole on the the right side of the casing to support the sound to escape from the speaker. To secure the breadboard in place, remove the non-stick paper from the bottom of the protoboard (breadboard) once you have drilled the holes and are ready to secure it in place.

Step 13: Inserting and Wiring the Pushbuttons

Next install the the audio trigger and volume pushbuttons. When inserting the pushbuttons, make sure to thread the wires through a hole and slide in the crush washer/nut on to the thread. Tighten the nuts until the buttons are all secured in place. With the buttons secured, you can begin wiring the buttons onto the protoboard. Wire routing is important and needed to prevent any unnecessary tension. Start your wiring by connecting the volume plus and minus cables followed by their ground cables. Make sure to connect the buttons in the proper order from 0-7 identical to their placement on the top panel. This will be important once you start uploading sound files. You can find the volume plus and minus pins visually marked as a + and – on the sound board for the audio trigger.

Step 14: Screwing and Wiring the Speaker

To mount the speaker, place it over the 1.25" hole that was drilled previously. The same screws that were used to connect the hinge can be used to secure the speaker. With the speaker mounted, connect the speaker to the breadboard to the output of the amplifiers 470uF capacitor and the other lead to the common ground. The wiring is now finished! It is time to upload some sound files to the soundboard!

Step 15: Programming the Soundboard

It is time to upload some sound files to the sound board. This soundboard requires the use of .WAV or .OOG files to play sounds. You can access a large selection of free sounds that can be downloaded safely in a .WAV format from freesound.org. Freesound offers a wide selection of audio effects that are user submitted by the community. It is a great resource for a non-commercial project like this. To start uploading files, connect to the soundboard via micro-USB and the other end the USB type A port. Locate the soundboard drive by opening the "File Explorer" application and navigate to "This PC" and find the drive with a name similar to "SOUND BOARD" and open the drive. Once you have downloaded some sound files, simply copy and paste or drag and drop the .WAV files to the drive.

Caution*

There are criteria for associating download files to different trigger locations.

  • You must name sound files that are onboard the sound board “Txx” where “xx” is replaced with the desired trigger location. An example of this would be “T00” or “T05” using this name will play the full length of the sound and then stop.
  • If you hold a “Txx” trigger the sound will repeat until you release the button and the file ends. You can also add suffixes to your downloaded files. “TxxHOLDL” will require the button to be held to continue playing the sound.
  • “TxxRANDx” where x is replaced with 0-5 will select a sound at “random” through all files with the same “Txx” location saved with the “RANDx” suffix. “TxxNEXTx” will act similarly to “RANDx”, but each file will be played in order.
  • “TxxLATCH” will continue to play the same sound on repeat until a new trigger is detected. Once you have finished uploading and configuring your sound files make sure to eject the device to protect the onboard memory.
  • Please note that you will not be able to upload sound files while the battery is connected to the circuit.
  • The sound board is also pre-configured by Adafruit to charge the battery at a safe amperage.
  • A charging battery should be placed in a well-ventilated area and should not be placed on a flammable surface or left unattended.

Step 16: Enjoy!

This concludes the guide on how to construct a case, build a circuit to support a soundboard, and program your own personal sound board.

*Potential Improvements

  • Since the Adafruit Sound Effects board does not supply a sufficient amount of voltage, use a 12V wall adapter to improve how loud the speaker can be.
  • Incorporate a heat sink on the LM386 to help reduce heat and noise.


Step 17: References and Data Sheets

References

https://www.adafruit.com/product/2220

LM386 N-4:

https://www.allaboutcircuits.com/electronic-compon...

Adafruit Audio Effects Sound board part no. 2220 (data sheet):

https://www.application-datasheet.com/pdf/adafruit...