“My Project” – A cell phone / Arduino based trail camera

A good friend had loaned me his trail camera during the COVID-19 lock down period of eight weeks. We’re still on level four with no end in sight. I returned his camera to him yesterday. I had learnt a lot using it and got some really great footage of animals roaming on my 1.6 hectare RaDAR playground.

In the meantime I’ve been experimenting using a cell phone activated through an infrared movement detector using the principle of a selfie stick. The signalling from the detector isn’t that intelligent though only having a NC (Normally closed) contact. The cell phone requires a decent timed signal.

So I introduced an Arduino NANO into the picture to handle all the critical processing and to make my camera a little more intelligent other than just using an infrared movement detector.

One of my CCTV cameras had failed so I replaced it with a spare I had. I dismantled the old camera removing the video section but keeping it’s infrared nighttime LED’s. I noticed they were controlled internally by a light sensor so that made the complexity of detecting night or day obsolete. I’ll simply turn the LED’s on, on movement detection switched through the Arduino like I do the camera.

Almost all camera apps react to a volume up or down signal and this is the principle on which selfie sticks work. Various resistor values across the mic connection are recognized by the app as commands. A 450 ohm resistor switched across the mic connections will be seen as a “Volume down” event and the camera activated.

Some apps react to short and “long press” events so the Arduino timing becomes critical. Having control of the source code makes that an easy task.

I’m in the process of building the “work in progress” into a heavy duty plastic container which includes a 7 A/Hr SLAB for long term battery supply to power the Arduino, detectors, infrared LED’s and to keep the cell phoned charged too. I intend to use my old Nokia 3 whose screen was cracked after a fall. The camera is still perfect!

Once everything is working and nicely tested I may paint it using camo colours. It’s simply a box you can place in the field somewhere strategic and enjoy looking at captured photos later.

It can even be used to capture trail runners as they pass specific points.

A work in progress – a “lock down” project 🙂

The initial code as a basic starting point ….. (Indentation removed by the WordPress editor)

// Intelligent cell camera
// by Eddie Leighton
// 20th May 2020

// ————————————-

int PIRSensor = 12; // NC Signal from PIR Sensor
int CAMERATrigger = 13; // Signal to relay board to trigger camera

int sense; // PIR Sensor sense variable

// ————————————-

void setup() {


pinMode(PIRSensor, INPUT);
pinMode(CAMERATrigger, OUTPUT);

//Serial.println(“Cell camera interface inititalised”);

digitalWrite(CAMERATrigger, HIGH); // Initialise trigger relay


// ————————————-

void triggerCAMERA() {

//Serial.println(“Camera has been triggered”);

digitalWrite(CAMERATrigger, LOW);

delay(500); // 470 ohm from ground to mic for 500 milliseconds

digitalWrite(CAMERATrigger, HIGH);


// ————————————-

void loop() {

sense = digitalRead(PIRSensor); // Test for PIR Sensor movement detection

if (sense == HIGH) {

delay(2000); // Allow two seconds for PIR reset

73 de Eddie ZS6BNE

RaDAR News – May 2020

Chris VA3ECO

Feedback from the April 2020 RaDAR Challenge.

Not everyone sends in a log but that’s okay as long as everyone had fun. There are no winners or losers in the RaDAR Challenge, you challenge yourself and your abilities giving what you have at your disposal.

Theunis ZS2EC was quite professional in his approach to sending in a log sending both ADIF and CABRILLO formats. Theunis is a regular contester and glad to see him being there in the RaDAR Challenge. The CABRILLO format was easier to read in a text editor. Theunis was abviously working as a fixed station. He was active for longer than the four hour period but he was there for others, mostly DX stations on 21 and 18 MHz in the morning and 7 MHz in the evening. Some stations sent a grid locator, hopefully some of them were also RaDAR stations.

My friend Greg Lane N4KGL always takes part in every challenge and makes regular You Tube videos of his activities. Greg always documents his outings on his blog and I encourage you to go and read his blogs and wath his videos. The URL to his latest report https://www.n4kgl.info/2020/04/april-2020-radar-challenge-report.html

Greg sent me his log via email and he wrote, “Eddie, Here is a file with the logsheets for the April 2020 RaDAR Challenge. I was assisted by Dennis WA6QKN. Lots of fun!”. Greg sent in a hand written log in the standard RaDAR Log format.

I received an email from Chris VA3ECO, “Hi Eddie, Here’s my log and pictures from my first solo RaDAR challenge. I was walking on the ice on Lake of the Woods, Ontario Canada.

You can post these pictures if you wish. Great fun!”. Chris sent in a hand written log in the standard RaDAR Log format. He was an “on foot” RaDAR station.

Sid ZS5AYC and Adele ZS5APT always take part in the RaDAR Challenges. South Africa’s biggest supporters. I did see Kobus ZS6BOS’s call sign mentioned in Theunis’s log but I’m not sure if he was active during the challenge.

Eddie ZS6BNE used the satellites during the challenge and the support from the satellite community in ZS was very good. His blog on his outing can be accessed on the URL https://zs6bne.wordpress.com/2020/04/05/april-2020-radar-challenge-done-and-dusted/ and well worth reading.

International lock downs due to the COVID-19 outbreak would have certainly had an effect on outdoor activities. Hoping we are still safe and healthy.

73 de Eddie ZS6BNE