beginners...help

Projects General Guidance
1

I have built a speech synthesizer following the website below.
practicalarduino.com.
And I have questions on the project.

  1. For the circuit diagram.(http://practicalarduino.com/schematics/speech-synthesizer-schematic.jpg)
    For the pin 1 and pin 5 of LM386, is it telling us to ground them directly? If so, the 2 ports of the speaker will be at zero voltage, how can we listen the sound ?

  2. For the cable used, is it possible to connect all the components(even for the speaker, Tx pin on arduino) by 3mm (thin-size) breadboard cable?

  3. Now, my situation comes. My green LED on the circuit board lights up. And the blue LED is blinking from time to time, indicating there is a signal on pin 16 on speakjet. But actually, there is no sound produced at the speaker. Is it the problem on the breadboard connection or the speakjet?

2

It's hard to read that drawing. However I think it's like the linked page below for their gain of 200 example:

Lefty

3

  1. Please get a copy of the National Semiconductor datasheet for the LM386.
    You will see from the examples that the capacitor only goes between pins 1 & 8.

  2. Yes.

  3. Review the dots on the schematic - pin 5 only goes to one side of the capacitor, the other side of which goes to speaker.

For audio projects, you really need an oscilloscope.
Download Virtual Analyser from here
http://www.sillanumsoft.org/ and with a stereo audio jack for your laptop soundcard you can make an audio frequency range 'scope that will let you look at signals in circuits like yours.

4

:DThanks all. It really works after reviewing the dots.
Thanks so much.