Tablets and Phones Augment Test and Simulation
Mobile engineering apps are proliferating as they enable mobile devices such as smart phones and tablets to provide a valuable assist in the office, lab, factory, and field. App developers offer myriad technical calculators and handy references. In addition, instrument makers have developed apps that let phones and tablets serve as the sole or auxiliary user interfaces to their products. In some cases, the phone or tablet itself becomes the instrument.
In the last category, I reported previously that the Speedy Spectrum Analyzer app can turn an Android phone into an audio spectrum analyzer, using the phone’s microphone as the input.1 In a similar vein, VR Mobile from Vibration Research uses a phone’s microphone as the input to a noise meter. VR Mobile also takes advantage of other phone sensors—the accelerometers—to measure X-, Y-, and Z-axis acceleration; it records minimum, current, and maximum acceleration for each axis. To further support the investigation of rotating or vibrating equipment, it can turn your phone’s display or camera flash into a strobe light with strobe rates to 30 Hz.
VR Mobile also offers a maximum-acceleration calculator, a unit converter, a sine calculator, and a shock calculator. The maximum-acceleration calculator shows how much acceleration a shaker can deliver based on the mass of the device under test; it covers shakers from Vibration Research as well as Labworks, Ling, Thermotron, TIRA, and Unholtz Dickie. The other calculators compute unknown values from known values entered by the user. For the sine calculator, you enter any two values for acceleration, frequency, velocity, and displacement; the calculator will display the other two.
Mobile Simulator
Not only can your mobile device serve as your instrument, but it also can be your unit under test or at least a model of it. Apps like EveryCircuit turn your Android device into a simulator. Models that come with the freeware version include various amplifier configurations, logic gates, a track-and-hold, a transmission line, voltage-controlled voltage and current sources, and an LED limiting-resistor circuit (Figure 1). Current-flow animations and an oscilloscope function that displays waveforms at each circuit node make the app an insightful educational tool.
As the developer notes on the product description at the Google Play Store, the free version “has limited sandbox area…. If you need a larger playground, a full version is available. The full version will employ all of your imagination and all the screen area of your tablet.” The full version costs $10.
Another tool that could benefit the educational environment is National Instruments’ NI Multisim Circuit Explorer for the iPad. NI calls the app a textbook curriculum companion that lets students investigate common electronic circuits, providing them with immediate feedback on the effect of modifying circuit electronic parameters. The initial release incorporates 18 circuits, covering RLC basics, filters, and op-amps. Concepts explored include Ohm’s law, voltage and current dividers, RC/RL step response, RC/RL filters, and operational amplifiers.
Also targeting educational and reference environments, the NI LabVIEW Intro app serves as a beginner’s guide to LabVIEW system design software, helping users understand the software’s fundamental building blocks by creating a virtual instrument for bridge monitoring. In addition, NI offers the NI DAQ Device Pinouts app, which allows users to easily access device pinouts for NI DAQ hardware. Users can search for their device, bookmark it, and access the product support page for manuals, specifications, and documentation.
NI offers other apps as well that can adapt smart phones and tablets for measurement and control applications while enhancing visualization capabilities and connectivity. For data acquisition and display, the company provides Data Dashboard for LabVIEW, which lets you create a custom and portable view for your LabVIEW applications on your iPad or Android tablet. You can connect to string, Boolean, or numeric data types and develop layouts of one, two, or four indicators. Data Dashboard Mobile for LabVIEW brings similar capabilities to your iPhone or Android phone, allowing you to display the values of network-published shared variables or web services as charts, gages, text indicators, and LEDs.
In addition, the NI cDAQ-9191 Data Display app lets you wirelessly take voltage measurements from an NI cDAQ-9191 Chassis with an NI 9215 C Series measurement module using your iOS or Android device. The NI cDAQ-9191 requires a firmware upgrade to enable compatibility with the app.
Finally, apps can help users get support. The NI SRManager utility enables customers with service contracts to contact NI support directly from the application and view a summary of their service requests, including email correspondence and notes entered by the NI engineering staff.
Agilent Technologies, too, offers mobile apps that aid measurement tasks. Agilent Mobile Meter is a free Android app that allows an Android device (smart phones or tablets) to connect to and control up to three Agilent handheld digital multimeter measurements.2 In addition, Agilent Mobile Logger is the free Android app that logs data and provides trending graph with Agilent handheld digital multimeters. Agilent Mobile Logger supports extension of data handling such as sending email or Short Message Service (SMS) automatically or line graph manipulation such as pan and zoom with the Android device’s touch screen.
Converting the Device to the Instrument
Oscium recently augmented its line of portable iOS-compatible products with the launch of its newest product, the LogiScope (Figure 2). LogiScope is a logic analyzer with the real-time data-analysis capabilities of an oscilloscope. The LogiScope transforms an iPad into a 100-MHz, 16-channel logic analyzer. With LogiScope’s triggering capability, decoded data can be viewed live, eliminating the need to capture, pause, and then view.
Courtesy of Oscium
The company says the touch screen-based iOS platform makes the display simple and intuitive. For example, changing the time scale is as easy as zooming into a picture on a smart phone, and adjusting the delay is as simple as a swipe across the top of the screen. LogiScope’s interface provides immediate feedback for signals that are too fast for the time scale by changing the waveform to red.
LogiScope version 1.0.12 is available for download free from the Apple App Store. The LogiScope app is made for iPod touch (third and fourth generation), iPhone 4S, iPhone 4, iPhone 3GS, iPad 3, iPad 2, and iPad. LogiScope hardware can be purchased for $389.99 from Oscium.
Oscium’s test equipment—which it dubs iOS Test—interfaces with the iOS family of products through the 30-pin dock connector. In addition to the LogiScope, the company offers the iMSO-104 Mixed-Signal Oscilloscope, the WiPry-Combo Spectrum Analyzer and Dynamic Power Meter, the WiPry-Power Dynamic Power Meter, and the WiPry-Spectrum Spectrum Analyzer.
Another test-equipment maker addressing the Apple family of phones and tablets is Redfish Instruments. The company’s iDVM Digital Multimeter (Figure 3) wirelessly connects to an iPhone, iPad, or iPod Touch via an ad hoc wireless network, allowing users to acquire, visualize, and share electrical measurement data on their Apple devices. The iDVM app can be downloaded free from the Apple App Store.
Courtesy Redfish Instruments
Redfish says the iDVM was designed for a wide range of users—including automotive technicians, advanced embedded systems engineers, electrical or building contractors, and field-service workers. The iDVM permits a user to log data over an extended period of time using the iPhone or the iPad as the storage device. For example, service engineers can use the iDVM to collect data and store it in a report for submission to their clients or keep the data on the voltmeter for their own records. Using the GeoTag feature of the iPhone or iPad, service engineers can even identify their location as part of the data. The iDVM uses rechargeable batteries.
Targeted and General-Purpose Apps
Mobile apps will continue to proliferate. Cerro Wire recently introduced its new electrical calculations app for the iPhone and iPad, which allows electrical contractors to calculate conduit fill, voltage drop, and amperage. Using the conduit fill calculator, users can enter the type of conductor, the size of each conductor, the type of conduit being used, and the length of the conduit run, and the calculator will return the recommended conduit fill. For voltage-drop calculation, users enter the length of the conduit run and the type of conductor, and the calculator will return the recommended conductor size based on NEC-recommended amperages. The amperage calculator simplifies an NEC amperage chart into a convenient calculator.
The app now is available on iTunes for dual download for the iPhone and iPad. Cerro Wire also plans to expand the app to Android.
Apps like the Cerro wire calculator are extremely targeted and specific, but you will find general-purpose apps as well. Wolfram|Alpha, for example, seems to have as its goal the emulation of the Star Trek computer, which could give intelligent responses to any question. Although the Star Trek computer had a voice interface, Wolfram|Alpha now offers a web interface accessible by PC or mobile device.
The Wolfram|Alpha website explains that while search engines look for textual matches, “Wolfram|Alpha uses built-in knowledge curated by human experts to compute on the fly a specific answer and analysis for every query.” As an engineering example, Figure 4 shows the partial results generated by Wolfram|Alpha in response to a query regarding a Chebyshev type 2 filter with 0-dB maximum gain, 0.5-dB maximum cutoff frequency attenuation, 40-dB minimum stopband attenuation, 1,000-Hz passband limit, and 2,000-Hz stopband frequency. In addition to returning the transfer function, pole and zero location plots, and Bode magnitude plot, it also returned a Bode phase plot, which would not fit on the Android phone display along with the other results.
What will the future look like for mobile apps? “Wolfram|Alpha’s long-term goal is to make all systematic knowledge computable and broadly accessible.” While the people at Wolfram|Alpha pursue that goal, you can expect other developers to continue to expand the range of targeted tools that augment test-and-measurement and related engineering applications.
References
1. Nelson, R., “Mobile Apps Support Communications Test, Data Acquisition,” EE-Evaluation Engineering, January 2012.
2. Nelson, R., “Bluetooth Enables Wireless Datalogging,” EE-Evaluation Engineering, May 2012.
For More Information
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Oscium