FlashVisio

Turn your smartphone into a digital oscilloscope able to capture visible/IR light pulses! FlashVisio can acquire a signal scan and take a measurement of the pulse duration.

The app can be used to analyze the behavior of a flash unit at different power levels or in general to measure the duration of a light pulse. Another particular application is to display the pulse train generated by an IR remote control. FlashVisio can also export flash data as files readable by LxMeter app.

In order to achieve these performances, you need to plug a special light sensor (SS06) into your smartphone. This sensor can be homebuilt according the following schematic:

SS06 schematic

Alternatively, SS06 sensor can be purchased already assembled and tested:

FAQ

(1) Why should I use the SS06 sensor ?
R: Unlike light sensors embedded in smartphones, SS06 sensor can measure light pulses of very short period. The minimum measurable pulse duration is restricted by the sampling time of the host ADC at a value of about 20 us.

(2) What is the calibration procedure for ?
R: The input stage of the microphone channel generally includes a high pass filter with a cutoff frequency of around a hundred Hz. Due to this filter, pulses of longer duration can be highly distorted as shown in the following figure:

Input filter

FlashVisio can compensate this behavior through the calibration procedure described in the manual. Note that automatic measurements of pulse widths are not affected by the calibration.

(3) When does the signal need to be inverted ?
R: FlashVisio always assumes to measure a positive pulse, and for this reason it uses a rising edge trigger. In the event that the light pulse causes a negative pulse on your Android device, you must select the invert option in the settings menu of the app.

(4) Why the pulse is followed by some sort of overshoot signal on my smartphone ?
R: Some smartphones use in their input circuit high-order high-pass digital filters that can generate spurious oscillation phenomena. However, the automatic measurement is generally not deceived by this behavior.

(5) Can FlashVisio capture the pulses emitted by an IR remote control ?
R: IR remotes generally generate pulses with a frequency of 38kHz, thus beyond the audio bandwidth. However, if the bandwidth of the analog input circuit of your smartphone is wider than 38kHz, due to the aliasing phenomenon, the signal will become visible and you will be able to take some measurements as for example the number or data packets or the period of them:

Screenshot7

(7) Does my smartphone comply with CTIA or OMTP standard ?

Smartphones known to support a OMTP jack connector:

- old Nokia
- old Samsung
- old Sony Ericsson (’10 & ‘11 Xperias)

Smartphones known to support a CTIA jack connector:

- Apple
- HTC
- latest Nokia
- latest Samsung
- latest Sony (2012 on)
- most Android phones

Note: SS06 sensor, if it isn't otherwise specified, comes with CTIA standard. If you own a smartphone that complies with a different standard you will need to use a CTIA/OMTP earphone converter adapter.

(9) How can I buy a SS06 sensor ?
R: Click on the "Buy" button and fill the form with your data, you will receive the best offer available at the moment, shipping costs included .

Your device doesn't operate as expected ?

If you haven't encountered your problem in the FAQ section you can report it or ask for further support at:

Please feel free to send us any comments or ideas that could be helpful in improving this application.