Signal to Noise Ratio (SNR) 90 dB (the typical SNR for a CD) 96 dB the Theoretical maximum for 16 bit Consumption (typical) <= 20 W (typical power consumption for a laptop) <= 10 W (4 x the maximum power consumption of the beagle bone black) Power Consumption (power saving mode) 5 W 2.5 W Voice Commands Accuracy 75% 85% Graphic EQ Band Count 5 bands 10+ bands On-Device Storage 1 GB 10 GB On Device Song Storage 50 (~500 MB) 1000 songs (~1 GB) External Song Storage 1000 songs (~1 GB) 1000+ Primary Device Size 20cm*20cm *3cm (LWH; 1200 cm^3) 15cm*15cm*3cm (765 cm^3) Primary Device Weight 2.3 kg (~5 lbs) 1 kg (2.2 lbs) Secondary Device Size 15cm*15cm*3cm (765 cm^3) 13cm*13cm*3cm (507 cm^3) Secondary Device Weight 2 kg (4.4 lbs) 1 kg (2.2 lbs) Maximum User Count 4 Users (@ 1000 songs) 8 Users (@ 1000 songs) Smart Playlist Algorithm Performance O(n), where n is the number of songs in the user’s Master Playlist (see section 4.2.2) O(1) – time to execute is independent of the number of songs. Playlist Accuracy: N songs, user skips S songs; Accuracy = (N-S)/N 50% 80% Song Selection Statistical Model relies on… Naïve Bayes or Binomial Logistic Regression Multinomial Logistic Regression Number of Attributes per Song 16 (with the possibility of unknown) 32+ (with the possibility of unknown) Unknown Song Attribute Rate 90% + (web scrapping might fail) 20% Number of Attributes per Song per User 16 (no unknowns) 32+ (no unknowns) Song Recommendation Algorithm Performance None O(1) Person Identification Accuracy None 75% Location Services None WPS Standalone GPS Combination of WPS and GPS Location Services Error Distance None <= 1 mile
SparkFun Electret Microphone Breakout Length/Diameter = 9.7mm Height = 4.5mm 100 to 10000Hz -46 plus or minus 2 dB 680 ohms 1.5V ADMP401 MEMS Microphone 4.72mm x 3.76mm x 1.0mm 100Hz to 15kHz -42 dB 200 ohms 1.5V to 3.3V USB Plug Mini Microphone USB size N/A N/A USB resistance USB voltage Mini 3.5mm Flexible MIC 12 cm long 30Hz to 16000Hz -62 plus or minus 3 dB 3.5 mm jack 3.5mm audio jack Table 3.5 A: Microphone specifications. Supply Current Working Voltage Input Additional comments SparkFun Electret Microphone Breakout Max 0.5 mA 1V to 10 V DC Termination Pins Need to connect to board we decided to buy ADMP401 MEMS Microphone 250 uA 2.7 to 5.5 V Termination Pins Need to connect to we decided to buy USB Plug Mini Microphone USB current 5V USB Need to buy a USB input Mini 3.5mm Flexible MIC 3.5 mm audio jack 3.5 mm audio jack Microphone is connected through a 3.5 mm audio jack Need to buy a audio jack 3.5 B: Microphone specifications, continued. Maximum Sensitivity to Noise Ratio Cost SparkFun Electret Microphone Breakout 58 dB $7.95 ADMP401 MEMS Microphone 62dB $3.95 Mini 3.5mm Flexible MIC N/A $2.79 Mini 3.5mm Flexible MIC N/A $1.97 3.5 C: Microphone specifications, continued further.
Continuous Is continuously taking in commands Available to take commands whenever Difficult for a recognizer to find a command. Low accuracy. Under continual development Table 3.5 I: speech recognition applications. is a way to use voice recognition through hardware and software. Through hardware, buying a module would be wise. The following are some modules Voice Recognition Module – Arduino Compatible, Model: AU_VOI_REC_00A This module can recognize up to 15 voice instructions and the package includes a microphone. To connect this to our main board a USB module will be needed. To program the voices a USB TTL module will also be needed. EasyVR Shield 2.0 – Voice Recognition Shield Can hold 28 custom speaker commands and as a UART interface. Table 3.5 J-K compare the two voice recognition modules. Size Commands Price Required voltage Current Voice Recognition Module -- Arduino Compatible 30 by 47.5 mm 15 23.50 4.5-5.5V Less than 40mA EasyVR Shield 2.0 - Recognition Shield 7.2 by 5.5 cm 28 49.95 3.3 to 5 V 12mA Table 3.5 J: Voice recognition modules Digital Interface Analog Interface Recognition Accuracy Comments Recognition Module -- Arduino Compatible 5V TTL level UART interface and GPIO 3.5mm microphone connector plus microphone pin interface 99 percent This module has many different options and settings. Require USB TTL module EasyVR Shield 2.0 - Voice Serial interface Microphone jack 99 percent Manual is very helpful channel
The company, VLSI solutions offers many ICs with the ability to both decode and encode MP3 files, as well as audio in many other formats. A few of their ICs are compared below VS1011 The VS1011 is a basic MP3 and WAV decoder. It offers the following features: Decodes MP3 and WAV files; Up to 320 kbps MP3 quality; Streaming support for MP3 and WAV; Operates from 2.3V to 3.6V; High quality DAC converter; 5.5 KiB RAM on chip for user code; Low operation; Bass and treble controls; Serial control and data interfaces; 4 GPIO pins Costs ~$20 VS1063 The VS1063 is a more advanced audio codec. It offers the following features: Encodes (in mono or stereo) at 8-48 kHz the following formats: MP3; Ogg Vorbis; 16-bit PCM; IMA ADPCM; G.711 u-law and A-law; G.722 ADPCM; Decodes the following formats at up to 48 kHz: MP3; MP2; Ogg Vorbis; MPEG4 / 2 AAC-LC(+PNS), HE-AAC v2 (Level 3) (SBR + PS); WMA4.0/4.1/7/8/9 all profiles (5-384 kbps); FLAC lossless audio (up to 24 bits); WAV: 16-bit PCM, IMA G.711 u-law and A-law, G.722 ADPCM; Streaming support; Upto 96 KiB RAM for user code and data; Unique ID for code protection; I2S interface for external DAC; High-quality stereo A/D converter; Serial control and data interfaces; Can be used either as a co-processor or as a standalone processor; UART for debugging purposes; New functions may be added with software and 12 GPIO pins; Ear Speaker Spatial Processing;
Bass and treble controls; 5 band equalizer; Low-power operation; High-quality on-chip stereo DAC with no phase error between channels; Zero-cross detection for smooth volume change; Quiet power-on and power-off Separate voltages for analog, digital, I/O SPI flash boot for special applications Costs ~$31 Although the VS1063 offers many more features and is capable of decoding in more formats than the VS1011 for an insignificant increase in price, the IC offers many features that the group won’t need it to perform. The group would like to build our own 5 band equalizer, so there is no need for the one included with the VS1063. The group is not interested in decoding the device being able to decode the Ogg Vorbis or WMA formats. And the group does not need an IC capable of encoding. Because of these several reasons, the group will use the simpler, and cheaper, VS1011. It offers all the features that we would like at a lower cost. 3.6.4 High Fidelity Audio The group would like to design a device capable of delivering high quality audio output; high quality audio is typically referred to as “high fidelity.” High fidelity audio can be described by the following characteristics: Low noise All digital will have noise due to the quantization process; Thermal noise will always be produced in the circuitry for temperatures above 0 K The group would like to aim for a signal-to-noise ratio (SNR) of at least 90 dB Little distortion Phase distortion can be caused by filters (used for equalization) with a non-linear relationship between phase and frequency The audibility of phase distortion can depend on various conditions Bessel filters have a linear relationship between phase and frequency Harmonic distortion can be caused by the non-linear components High fidelity devices tend to have < 5% Total Harmonic Distortion Accurate frequency response Excluding any desired equalization effects Humans can hear at around a range of 20 – 20k Hz 3.6.5 Volume Leveling The group would like to implement some sort of volume leveling module; due to the “Loudness War,” newer music can be significantly louder than older music. The group would like to prevent any harsh changes of volume between songs. There are a few ways