With Android continuing to make inroads across the board (64% market share in tablets and 53% in smartphones as of Q1 2015), it's time to take a look at some cool Android apps for analog EEs.
Here are six that are worth considering. What are some of your favorites?
Spectrum Analyzer: The Raspberrywood audio spectrum analyzer ( free; premium version $0.99) features a 44.1KHz sampling rate and 8192 samples per spectrum in the free version. Also included is peak detection,
tap to pause, and the ability to take a screenshot and export it to the gallery. It's also ad-free.
The premium version adds an adjustable FFT (up to 100k samples), an adjustable sample rate (8k – 48kHz), autoscaling, an adjustable manual scale, and other features.
SPICE Program: The DroidTesla(free; pro version $12) , developed by Vladimir Djokic, is a simple but powerful SPICE engine that solves basic resistive circuits using Kirchoff’s Current Law (KCL); the simulator systematically forms a matrix in accordance with KCL and then proceeds to solve for the unknown quantities using various algebraic techniques such as Gaussian elimination and sparse matrix techniques.
For a non-linear component, such as a diode or BJT , the program uses the Newton-Raphson iterative algorithm to solve circuits with non-linear I/V relationships.
For reactive elements(capacitors and inductors), the DroidTesla uses numeric integration methods to approximate the state of the reactive elements as a function of time. Currently DroidTesla offers only the trapezoidal integration methods to approximate the state of the reactive elements, but the Gear method is under development.
CAD: palmDraft (free; full version $2.99). Originally designed for the palm OS (remember that?) back in 2002 and subsequently ported to Android, the palmDraft is a bitmap-based CAD, featuring a high definition, flick-panning, pinch-zoomable working canvas optimized for finger and pen drawing. The schematics file format is standard .png bitmap file format which can be easily exported and shared for printing.
Schematics can be in 3 sizes (up to 1920×1080 pixels). There's a built-in library of standard analog and digital symbols, and custom symbols and ICs may easily be created or imported. There's even a selection of vacuum tubes!
Digital Oscilloscope: The Osciprime Oscilloscope (legacy version free; enhanced version $5.48) is a fully-functional open-source Android oscilloscope, released under GPL. It works with both the standard microphone input and the two-channel OsciPrime interface board, available separately.
The software itself includes standard o'scope functionality (trigger, interleave, measurement, attenuation, offset etc.), and features a sample rate of up to 44.1 kHz with the microphone input. The hardware board extends the bandwidth up to 8 MHz, depending on gain, and features five analog gain levels, an input voltage of up to +-16V, and up to 6Msps with 8-bit resolution. The board allows the use of standard 10X probes (2-channels) and communicates via a USB interface.
Equation Solving Tool: The Royal Solver Lite (free; Pro version $4.95) is a Swiss Army Knife for technical problem solving. The full app contains 550+ equations covering Mathematics, Statics, Kinematics, Dynamics, Electricity and Magnetism, Fluid Mechanics, Temperature and Energy, Heat Transfer, Machine Elements, Stress/Strain and Aerodynamics. For any equation you pick the variable you want to solve for, enter the other data, and then the magic happens.
The Electricity & Magnetism section includes equations related to electric fields, voltage, current resistance, capacitance, magnetism & inductance.
The Lite version allows use of a subset: for example the Electric Charge & Field area has 18 different equations; 4 are available in the Lite version.
Mobile Document Scanner: CamScanner (free; various paid options) allows you to use your mobile phone to scan offline documents and synchronize them across different machine. The free version is ad-supported and scanned documents contain a watermark. Advanced features require a subscription ($4.95/mo.), but add 10G cloud storage, auto uploads to Dropbox, Google Drive, etc., and OCR editing of scanned documents.
Thanks to my old work buddy, Steve Everson, for this. Steve says, “This is great for capturing anything from the receipts or business cards during a trip to white board scribblings or a scope shot on an old scope without a USB interface. It really can take the place of a scanner since it provides aspect ratio correction with cropping so just the document you wanted is saved. It will also provide some nice preset image enhancements that can make the finished product more legible.
The images can be grouped and labeled in ways that form a complete document or set and then shared as a multi-page pdf. It also can be set to automatically back up to an on-line service which will then sync to all your devices which are registered on your account. This is one of the best and easiest to use camera based scanners I've run across.
Of course, there are now dozens of cool Android apps for cool guys like us. Which ones have you found particularly useful in your work? Let us know!