While designing the SpeakJet Shield, I considered adding an on-board speaker. The speaker would have been quite small, with such limited space available on the shield. I intended to first put the SpeakJet Shield into a small robot, which produced a lot of motor noise, and I could not find a small speaker that was loud enough for me to easily hear. That is how the current SpeakJet Shield design evolved - one that would allow for attaching a larger speaker or it could be connected to a more powerful audio amplifier.
The current SpeakJet Shield PC board allows several methods to attach a small speaker: by directly soldering speaker wires to the PC board, via a C-grid connector if you buy my TTS Deluxe kit, or via the earphone jack. The method you use is up to you, and probably will depend on what you have available.
The speaker seen in some of my photos and videos is one I purchased from Pololu Robotics and Electronics http://www.pololu.com/catalog/product/1262 . It is a 50 mm (about 2 inch), 8 ohm speaker and, so far, it seems to have enough volume for most of my planned SpeakJet Shield projects.
I now offer a SpeakJet Shield TTS Deluxe kit which includes a speaker pretty similar to the Pololu one.
Speaker wire connection to the SpeakJet Shield:
The least expensive method to connect a speaker is to directly connect the speaker with wires to the PC board. 24 gauge stranded wire fits easily through the "speaker" holes in the board.
Cut two pieces of 24 gauge stranded insulated wire, approximately 6 inches (15 cm) long. You can go longer if you need it to reach a speaker mounted somewhere, but longer wire becomes more likely to pick up electrical noise in the audio.
Strip off approximately 3/8 inch (7 mm) of insulation off both ends of both pieces.
Slightly twist each of the bare ends to keep the strands together.
With your solder iron, tin all the bare wire ends.
Poke the wire into the two "SPEAKER" connections, one wire for each connection, on the SpeakJet Shield PC board.
Solder each wire end to the pads on the PC board. Clip off any extra bare wire so it is about the same length as the other leads under the PC board.
Poke the other bare ends through the speaker terminals; bend them in half so they hold.
Solder the wires to the speaker terminals.
Your speaker is attached; go have fun programming your new SpeakJet Shield...
Amplifier connection via the earphone jack:
You may also use the earphone jack connection to connect to a more powerful audio amplifier. The amplified speaker sets that plug into a computer work very well for this! Most use a stereo mini-plug, which is the same size as the earphone jack on the SpeakJet Shield. Just plug into the SpeakJet Shield earphone jack. If the audio sounds distorted, you may need to decrease the volume from the SpeakJet Shield by adjusting the "VOLUME" trimpot on the SpeakJet Shield PC board.
Next: Programming tutorials...
Programming the SpeakJet Shield Basic
Programming the SpeakJet Shield TTS
SpeakJet Shield TTS/Basic by Galen Raben is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License.
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