PD Pi Uno and Sharp

Naïve Schematic

The object of my research at this point in terms of electronics, coding etc, is to control the audio output of a sound file using Arduino and an active IR sensor and that this system should be fully automated and self starting using a Raspberry Pi coded (perhaps) with Pduino. 

I have looked at the possible components one by one and have arrived at the following which are open to change once I consult with Ed as to their suitability and viability.

This list may work as an indication of what I plan to use so as to gain, at least, a basic understanding of each component part. The coding is something else that I will have to be learnt over time once I procure the parts. 

Raspberry Pi 3: used to command the Arduino controller. The reason for this is to make the system automated only requiring to be switched on without the need of a laptop to initiate the programme.

 

Arduino Uno: having researched the myriad of Arduino models, this one comes up as the universal board that will do most things. I don’t need particular miniaturisation or a large number of I/O pins.

 

Active Infra Red Sensor: for a proximity sensor capable of analogue output and differentiating distance. It has to be active with a both a IR transmitter  and receiver. This sort is called an active (as opposed to passive) sensor. There are various models with different ranges. Other types of sensor include ultra sound sensors which are only suitable for detecting hard reflective surface. People do not make good reflectors as they absorb sound, particularly when clothed. On the other hand, people emit plenty of IR radiation. Sharp appear to offer the best range of sensors at a low price.

 

Digital potentiometer: to translate the distances picked up by the sensor and translating them into variable voltage that can be used to regulate output.

Media player: which stores and plays the sound files to be controlled. I do not yet know which type, whether incorporated in the Arduino, stand alone, usb stick or using the Pi as a media player. I suspect that using the Pi as a media player might complicate matters and a stand alone player might be simpler to incorporate in physical wiring. This I need to find out.

 

The speaker(s): I intend to use range from small to very large. The large one – 10 inch 4 Ω will need an amplifier that can deal with that low impedence. It will also have a particular case volume requirement, but that should not be a problem as the speakers positioning is not critical. 

 

Breadboard and connectors: There are many sizes and types of breadboard which facilitate wiring without the need to solder. With this I will need  jump lead connectors.

 

Resistors and capacitors: needed to regulate current in the circuit and perhaps a capacitor to help even out fluctuations in current. This may not be necessary when employing an amplifier. I shall find out in due time. 

LED: to test the circuit and proof of concept

 

 

Amplifier: is needed to amplify the sound signal and protect the Arduino circuit board from being ‘fried’ by the current drawn by the speaker(s). The amp takes the signal in the form of a small current and amplifies it sufficiently to ‘drive’ the speaker physically – which works by forcibly vibrating a drum-like membrane via voltage oscillations in a solenoid. I have a number of amplifiers from old HiFi systems. Alternatively I could get a smaller amp board; which one depends on the requirements of the speaker. A small amp size would be preferable for logistic and space reasons.

Multimeter: for measuring current, resistence, capacitance, voltage etc. Necessary to ascertain values and ensure connections are sound. I do not need an expensive model as it will not need much use, certainly not heavy duty and robustness is not an issue in the studio. 

Sound files: whether mp3 or wav may not be important since the sound I intend to use would not suffer from being in high fidelity. After all, most output nowadays is in mp3 and the relative loss of detail is hardly noticeable in normal circumstances.

 

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