Let's Make Robots!

audio

Upon starting my Arduino adventures/misfortunes one of my first projects was hooking a resistor and an LED to the board and making it blink. But just like those … Read more
As all inventor one should have an assistant. I wanted one like IGOR but as I don't have any hunchback friends and have no plans of digging up corpses and … Read more

Getting SOUND from your Picaxe (Works with other controllers also).

WARNING:  If "techie-stuff" makes your head hurt, do not read the following. 

      (ha ha)

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To make sound from your picaxe, the manual shows a 10 uF capacitor in series with a 40 ohm speaker.

This will work but gives a very low volume sound.

Plays wave files from a AVR based MCU with very little external hardware!
Using a
Last year I wanted to add sound to a bot so I wrote a program that plays wave files.  I later rewrote it so that it would be completely interrupt driven so that I … Read more
Navigate around while avoiding obstacles with ultrasound, infrared light and air pressure based bumper sensors.
Using a
Flashes light to beats in music
Flashes LEDs to beats in music. The concept is simple. Two FETs act as switches, and turn the LEDs ON when sufficient current flows through its base terminal. The … Read more

How do I filter audio?

I just successfully hooked up an electret microphone to my PC, without burning either. I use a very simple circuit to pre-amplify the signal, using a single general purpose transistor (2n3904). The microphone is electrically separated from the amp by a capacitor (.1 uF). The same trick (.01 uF) is used between amp and PC.

Audacity is able to record sound and display levels. I am getting decent range across the audible spectrum.

Simple Audio Preamp

i found an easy to make audio preamp that i intend to use to measure a sound with an ADC input on my arduino. i want my robot to respond to me clapping and start a drumming sequence. I may have to use some aditional circuitry to turn the output to a simple high pulse when the sound goes above a certain level, this way i can use one of the arduino interrupt pins to start the sequence at any time. heres the link:

 http://www.reconnsworld.com/forum/read.php?9,10

here is someone who has used it with an avr chip

Plays musical notes using a non-contact LED stylus.
This is 'Allura' - a small synthesiser I built as a platform to test out a few techniques for another project in progress. Read more

Noisy LM386 based audio amplifier

Inspired by this post from Salvage, I ordered a couple of gameDR Smack Talk for the XBOX units. The volume is way too low to drive a speaker directly, so I need an audio amplifier.

That led me to this post from Calculon320 on building an amplifier with an LM386. I breadboarded the audio amp, and it definitely amplified. However it also added a lot of noise. It could be cleaning it all up on a perf board would fix some of that, but it is very noticable.

Boosting Speakers with the Lm386

Hey All,

So I'm integrating the SpeakJet into my next project, and using the LM386 to try to boost the speakers. Unfortunately, the package didn't include any circuit (or information whatsoever, really) and Radio Shack has discontinued their databooks. So I went to the go-to info tool, THE GOOGLE! I've seen this circuit all over the place:

lm386_0.gif

A few questions about this circuit:

1. Is the .05uf cap and 10 resistor recessary if it's just going to ground?