Onyx Labs - Oscilloscope & RTA for IOS

Started by Elantric, February 04, 2016, 10:25:17 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Elantric

Onyx Labs Oscilloscope for IOS
http://oa.onyx3.com/







http://youtu.be/U8bXpzppdR0?list=PLXir1xfAuDCNv-Y-ubt8xA6QQx6GQWDq5
I use this for analog, and audio measurements. Attach an Apple USB adapter and a $40 stereo A-D converter available online, and my iPad is like a $300 O'Scope." -thymeout-

Oscilloscope app is great for analyzing audio range signals, or learning oscilloscope measurement basics. The interface includes many standard oscilloscope controls, such as: triggering, time and voltage per division, signal measurement cursors, and more.

The app incorporates a signal (function) generator capable of generating sine, square, triangle, and sawtooth waveforms of up to 22 KHz. Calibration to an external reference signal is supported, guaranteeing the accuracy of measurements.

Input can be acquired via the built-in microphone or an external mic/probe connected to the headset connector. For best results, use an external audio interface connected to your device dock. This allows for standard audio equipment to be connected, as well as for dual channel input. Oscilloscope probes also be connected (using a BNC connector). When feeding external signals via probes, you should take care not to exceed 1V AC voltage. Currently iDevices support only AC input.

For up-to-date information on feeding signals and currently supported audio interfaces, please visit http://oa.onyx3.com


Feature Highlights:
● Real-time waveform display (60 FPS)
● Triggering modes: Normal, Auto, Single
● Set trigger level and pre-trigger time
● Dual channel signal generator
● Reference signal calibration
● Pause function to get a screen capture
● Export traces as text file for further analysis
● Measure signal data using cursors
● Use "finger pinch" on screen to set voltage and time base
● Double tap screen to enter Black Panel mode
● Three color themes to choose from
● XY mode for viewing Lissajous figures
● Frequency range 20Hz-22KHz
● Native iPhone 6 graphics


http://oa.onyx3.com/signals.html
Feeding External Signals Into the iDevice

Dock Connector

For best results, we recommend using an external audio interface. This allows for standard audio equipment to be used, as well as for dual channel, unfiltered input.

Some audio interfaces are Apple MFi compatible and plug directly to your iDevice dock connector. For generic USB audio interfaces, you can use the iPad Camera Connection Kit as an adapter.

We have tested the following devices, they all provide line level input, and some of them would also have line/mic level switch:

Sonic Port Audio Interface
Sonoma Wire Works GuitarJack
Numark STEREO|iO
Behringer UCA202
Griffin iMic
Microphone Jack

For feeding signals directly to the microphone jack, things get a bit complicated as the iDevice expects a particular load in order to "detect" an external microphone. To actually use the mic in, you should have a 1K resistor in parallel with the input. Alternatively you can use an adapter cable such as this one, which was apparently designed to address this.

Using Oscilloscope Probes

Check out Nicolai Steinkamp's article on making your own DIY audio scope probe. When connecting external signals via probes, you should take care not to exceed 1V AC voltage.



The pic above illustrates some ways of attaching probes to iDevices -- using USB audio interface for the iPad and a KV Connection cable for the iPhone/iPod touch.


--

Oscilloscope probe for iPod, iPhone and Android
Pretty much in all App Stores and Markets there are several oscilloscope programs with which one can make its electronic companion to an almost full and the digital oscilloscope. For this, the microphone input is used, the measurement allows to 44.1 or 48.0 kHz. Even triggers is possible! Also for the Pc there / time to create a series of diagrams (even free and very powerful) programs to voltage. Here even a 2-channel representation is possible thanks to a stereo input.

I want a few Introducing:
PC:
http://www.zeitnitz.de/Christian/scope_de
iPod / iPhone:
http://itunes.apple.com/de/app/oszilloskop/id388636804
http://itunes.apple.com/de/app/signalscope/id284781777
Android:
https://market.android.com/details?id=com.nfx.noscpro

However, this microphone input can only handle voltages up to 2.1V. That is why I am presenting my self made probe, with which I can measure higher voltages. The scheme is actually quite simple and based on a simple voltage divider. The input voltage is split by two resistors in two smaller voltages. The ratio of the voltages is to drop the same as the resistances to each other: R1 / R2 = U1 / U2.

In my application while a resistor with fixed 1,2kOhm and the other via a slide switch is variable. This allows you to select various duty cycles, which you calculate in advance swiftly. I have there times prepared something ....

The microphone input from Apple, as well as with most Android devices need to initialize approximately 1k. It may therefore be necessary to move the slider to the 1 at startup: to bring 1 position. Therefore, the fixed resistor with 1,2kOhm is also good sized: not too low to avoid unnecessary load on the measurement source and also not too high, so that the input will be activated. The most common duty cycles I've been here in the wiring diagram precisely. But Underneath is the final formula with derivation to realize other.

If you want to measure higher voltages, but also the security should not be neglected, so that no one grilling his toys. In addition I have installed just before the entrance to the 4-pole jack plug two Zener diodes with 2.1V, which close the entrance in case of exceeding short. The value of the Z-diode is not strictly adhered to meticulously. There may also be a lower or slightly higher value, the characteristic is not ideal anyway. You can also take two suppressor diodes, which then also tolerate more power and in the case of the case do not fry quickly.

Newer iPhones seem to cause problems with the detection as an accessory. One solution is to me currently unknown.

So, now enjoy handiwork.

Elantric



Spectrum Analyzer for iOS is a powerful real-time audio analysis app. Designed with musicians and recording engineers in mind, it can also be used by anyone interested in the world of sound. Ideal for room tuning or speaker tuning, the app enables portable, precision audio measurement and visualization.

Elantric