Android App to control Arduino DRT (USB remote control)

Source code is available in our GitHub repository: https://github.com/InstituteOfErgonomics/drtrc

A compiled Android app can be installed via the market: https://play.google.com/store/apps/details?id=de.tum.mw.lfe.drtrc

Head-mounted detection response task (HDRT); Demonstration

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How to use the Arduino / Android DRT setup

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The app is a remote control to operate an Arduino Detection Response Task (DRT) device  in an experiment. These Arduino DRT devices do the experimental protocol on their own and save the results to an SD card and/or transmit the results via Ethernet (e.g., to a driving simulator). With the remote control app, an USB OTG adapter and with a phones/tablets with Android version newer or equal 3.1 and OTG-capable you are able to: * provide power to the Arduino device from the phone/tablet * send control commands (e.g., start/stop, test stimulus, set marker, etc) * see status messages during the experiment (e.g. current reaction time and hit rate) The combination of the Arduino and an Android app for the DRT provides a cheap and comfortable setup for the experimenter. Each platfrom (Android, Arduino) can provide and do in the setup was it can best. The Arduino provides an easy environment to connect hardware I/O and meet realtime contraint without a realtime operating system. The Android device provides power (via USB OTG) and a touch screen to observe and control the experiment. It is important to note and understand, that the app is (at the moment) a remote control and status display for the Arduino DRT setup: Therefore, no experimental data are stored in the app on the phone. The data are stored on the Arduino DRT SD card or transmitted via Ethernet e.g., to a driving simulator. Note: The benefit that the Arduino is powered from the phones battery has the drawback that the state of charge can quickly decrease. Some high current motors maybe can not even be powered via USB OTG. There are USB OTG adaptors which allows to connect a power supply. This would enable to power high current motors and would not lower the phone battery.

Tactile tactor on Arduino DRT when powered by smartphone

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Get an indication if TDRT tactor probably evokes fast or slow reactions

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In an experiment we used different tactors which influenced the baseline reaction times of a test group between about 250ms – 350ms. Thus, your absolute results depend on the tactor you use.

In the Arduino plainDRT we implemented an (empirical/experimental) measurement function which tries to get some information from the tactor via back electromotive force (BEMF) and tries to predict what could be an outcome of a baseline experiment (just the reaction time of TDRT without other tasks). The tactor is switched on 10 times and in parallel some values are measured. The motor in the video would have a predicted value of 257ms and thus is one of the more “fast” tactors.

Important: use during the BEMF-measurement EXACTLY the same setup (PWM value, cables, power supplies, etc.) like in the subject experiments!

At the moment we use the predicted value only as indication. We would be thankful for your feedback. The later aim, is that this value maybe can be used as plausibiliy check.

This documentation is not in the public domain, but the following is valid for it:

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