const int geigerPin = 2; // the pin number connected to the Geiger counter output
volatile int count = 0; // variable to count the number of pulses
void setup() {
// put your setup code here, to run once:
pinMode(geigerPin, INPUT); // set Geiger counter pin as input
Serial.begin(9600); // initialize serial communication
attachInterrupt(digitalPinToInterrupt(geigerPin), pulseCount, FALLING); // interrupt on falling edge of Geiger counter pulse
pinMode(13, OUTPUT);
pinMode(5, OUTPUT);
}
void loop() {
// put your main code here, to run repeatedly:
delay(60000); // wait for 1 minute
detachInterrupt(digitalPinToInterrupt(geigerPin)); // disable interrupt
float cpm = count; // * 60.0 / 60000.0; // calculate counts per minute -- this seems wrong
// Serial.print(cpm); // print counts per minute //
Serial.println(cpm); // print counts per minute
count = 0; // reset count
attachInterrupt(digitalPinToInterrupt(geigerPin), pulseCount, FALLING); // re-enable interrupt
}
void pulseCount() {
count++; // increment pulse count
digitalWrite(13, HIGH);
tone(5, 3800, 5);
delay(50);
digitalWrite(13, LOW);
}
# Configure serial port settings
$port = new-Object System.IO.Ports.SerialPort COM3,9600,None,8,one
# Loop indefinitely
while ($true) {
# Read integer from serial port
$port = new-Object System.IO.Ports.SerialPort COM3,9600,None,8,one
$port.Open()
$number = $port.ReadLine()
# Write number to file
$path = "\\samba\dean\web\counts.csv"
$timestamp=get-date -format s
# // $NewLine = "{0},{1}" -f $date,$number
# Format the data as a CSV string
$data = "{0},{1}" -f $timestamp , $number.Trim()
#// $NewLine | add-content -path $file
# $string=$date,$number
# //Add-Content $path $string
# Append the data to the file
Add-Content $path $data
echo $data
$port.Close()
}
This is a comparison of the broadcast band during the day (at top) vs at night (bottom). Many stations are required to lower their power and/or change their antenna directionality at night because the absorptive D region of the ionosphere disappears and allow lower frequency waves to propagate via a skywave. Some stations, called clear channels, are allowed to maintain their high power at night. Chicago happens to have quite a number of them-- you can see them at 670, 720, 780, 890 and 1000kHz. Local stations including the clear-channels are marked (minus 1690). At night, you can see a carrier at nearly every 10kHz, showing many of the AM stations listenable at night from across the US. WSCR 670 and WBBM 780 are unfortunately also using HD Radio.
Local switching power supply noise appears as very impulsive (fast horizontal bands) at about 615, 925, 975, 1090, 1230, 1500, 1550 and 1850kHz. The fundamental for some of these appears to be at 306Khz. You can see in the IF this signal, as well as the much weaker DGPS signal at 304kHz from Mequon,WI.
This was taken with a simple indoor dipole of 42ft length (with some turns in it) and a RTL-SDR.com v 1.3 dongle with HF direct sampling (Q-branch) and AGC turned on.