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ANDROID PIC16F1459 OSCILLOSCOPE
The input is to pin 13, pin 14 is comperator input. This scope is
for low frequencies, up to 5KHz. The sampling is done by the PIC ADC in a
speed of about 60K sampling per sec. The software for Android is in B4A
basic for android. The pic takes 62 samples of input to create one screen.
For lower frequency a delay for each sample gives slower sweep. The Android
app set to USB CDC class. To install the app on Android device place the APK
file in the device and open the file. Load code to the pic and connect it
via OTG cable. OTG (On The Go) is the cable that is used to connect USB
devices (other than charger or PC) to phones or tablets. Input is DC or AC
not acceding 5V.The Analogue Comperator of the PIC detects zero crossing of
input signal, it triggers start of sampling a frame when signal is rising.
Software for PIC and app for Android, if you wish to change it download free IDE from:
https://www.b4x.com/
 
ANDROID ARDUINO OSCILLOSCOPE
Low frequency oscilloscope for Android using
Arduino Uno or Nano. The input is to pin A0 of the Arduino which connected
to Android device via USB OTG cable.This scope is for low frequencies, up to
5KHz. The sampling is done by the Arduino ADC in a speed of about 20K
sampling per sec. The Arduino software is mostly in Atmel code in purpose to
get wider bandwidth. The software for Android is in B4A basic for
android. The Arduino takes 60 samples of input, 60 samples create one screen.
For lower frequency a slider gives slower sweep.To
install the app on Android device place the APK file in the device, when you
open the file it ask if you want it installed. Load code to the Arduino and
connect it via OTG cable. OTG (On The Go) is the cable that is used to
connect USB devices (other than charger or PC) to phones or tablets.Input is
DC or AC not acceding 5V.
The Analogue Comparator of the mc (pins 6, 7)
is used to detect zero crossing of input signal, it triggers start of
sampling a frame when signal is rising.
Software for Arduion and app for Android, if you wish to change it download free IDE from: https://www.b4x.com/
Android app in App-Inventor can be downloaded from GitHub. https://appinventor.mit.edu/
You are free to use the circuit diagram and the software with no
limitations.
 
Circuit Description
See also Technical Tips
100K resistors set input to 2.5V to run signal at center of
screen.
Arduino pin A0 and PIC pin 13 are inputs for the signal.
Arduino pins 6, 7 are inputs of the analogue
comparator, the comparator detects zero crossing and triggers start of
frame.
ANDROID MICROPHONE OSCILLOSCOPE
Oscilloscope app for Android with input to the microphone socket. Low
frequency oscilloscope no need for external active components. Microphone
input is 0.5V max, AC signals only, the input is connected to the device ADC
via a capacitor. The bandwidth is about 30 to 5000 Hz, the cap coupling
causes the lower limit, the slow basic program and the device ADC define the
upper limit.
The sampling rate is 44.1Ksps Arduino takes 60 samples of input, 60 samples
create one screen, for Y x 10 every tenth sample is taken.
App is in B4A (basic for Android), To modify the app to your needs you
can download the free IDE from
https://www.b4x.com/ To install the app download APK file
and open it in your device.
Input is to the microphone socket. Input voltage divider allows signals
of 5V P-P. Alternative way is to use an existing headset and connect the
input in place of the mic. When no input plugged in the scope shows the
signal from the internal mic. The 18 ohm resistors simulate speakers, it
lets the device switch to external mic.
 
Circuit Description
See also Technical Tips
100K, 10K resistors are voltage divider to set the input to
5 Vp-p
18 ohm resistors are to simulate speakers, it lets Android to
switch to external mic. |
Technical Tips