bent circuits audio question

How are the boards powered originally? Which voltages do you need?

heliosoph

Keith

Yes you can use regulators to provide power for each of the different 'bent circuits'.

It may be that one supply is enough for a number (assumming the same voltage).

The output of these devices may vary, so you might need to do some experimenting.

Some rely on the speaker impedance to work, so you might need to substitute a resistor.

Some may have a bit before the speaker you can tap into.

The easist way is probably to try each with a set of powered computer speakers.

You may be able to equalise the volume by changing the resistor value that you added instead of the speaker.

Once you have the various outputs, you can use a 47uF from each, to join into the input of your amplifier.

Mark

The toys were originally battery powered , from 3v to 4.5v. The power source for the entire project 12v, 8amp.  I am using a buck, step down converter to bring it down to 7v for the arduino.  The project includes steppers, dc motors, and servos, all of which are powered from a 7v terminal (12v for the dc motors). An LM317 regulator provides the precise voltage.

I appreciate the audio details.

Here is a really dumb question; I'm replacing the buttons that activate the audio with wire.  When these leads contact the ground, the audio plays. Voltage, button wire to ground = 3.5v.  When in direct contact, voltage is zero when the audio plays. How can this be wired to the Arduio?  The boards are easily fried so I would rather display my ignorance than destroy even more of them!

An NPN transistor and simple sketch solved the problem by connecting the transistor output to the board ground and the positive from the regulator directly to the button wire.

Keith

The transistor is the safest method.

I would have thought the Emitter would go to ground, Collector would go to the other button pin (that has 3.5v). The Base would go to the Arduino THROUGH a resistor of 470 to 1K ohms.

You could use an optocoupler, which has the advantage of being the same for any buttons that connect to +ve supply voltage (rather than to ground).

The collector of the optocoupler goes to the most positive voltage pin.

Your Arduino should be more than capable of handling 12v in.

Just be careful with the amount of current your step down converter supplies, as servos and steppers will draw twice (or more) of their running current when they start moving.

The boards are easily fried so I would rather display my ignorance than destroy even more of them!

Caution is always a good thing....

mark

Hello keith,

you could use the voltage that comes from the arduino board to power your devices. I would take 5V for the 4.5V devices and 3.3V for the 3V devices. This should be ok because when you run it from a new battery voltage is higher than the nominal value of the battery. 5V and 3.3V are both supplied by the arduino board.

heliosoph

Friedrich

You are quite correct regarding the voltages.

Depending on the particular Arduino board, the current capabilities may not be enough.

Keith's approach to seperate supplies and careful consideration ensures that minor 'accidents' don't render him with a damaged board.

A few dollars for a regulator is a small price to pay for peace of mind.

Mark

Mark

It's right what you said.

For seperate voltage supplies I would take the 78L05 for generating +5V (two additional capacitors necessary) and the LM317 (two additional resistors) for +3V. Or you can take two LM317 and adjust both voltages to what you want. Tools for dimensioning the two resistors can be found online.

heliosoph