Published April 4, 2022 © MIT

Overengineering your workshop lighting

I used a 60GHz radar for motion detection to illuminate my workshop while keeping the sensor hidden

BeginnerFull instructions provided2 hours411

Things used in this project

Hardware components

Infineon BGT60LTR11AIP Autonomous shield

Infineon XMC2GO - industrial microcontroller kit

Software apps and online services

Arduino IDE

Hand tools and fabrication machines

Soldering iron (generic)

Story

I built a small workshop in my apartments basement but the original lighting setup was to small and not sufficient for my prototyping needs. I decided to build myself a nice bright LED panel out of some left over parts - a sheet of aluminum for heat transfer, a view meters of a LED stripe and a 24V power supply. And here I stopped working on it and switched it on and off by pluggin and unplugging the power cable for a year now.

New sensor - new opportunity

I have always been fascinated by radar technology - it somehow has some dark magic touch to me. But it was also pretty hard to work with it since its software and electronic design was quite challenging. Recently I heard about a new 60GHz sensor board from Infineon, the BGT60LTR11AIP shield. This solves all my concerns as all antenna design and raw radar processing is integrated in the radar chip! You directly receive the information of a motion and its direction via a 2 digital pin interface, PD (direction) and TD (motion):

BGT60LTR11AIP shield on breadboard

That's sounds too simple and therefore I had to give it a try!

Adding a power stage and DCDC converter

Of course you can't switch a 24V LED panel directly with this sensor board.I opened my "box of former projects" and found a smart low side switch (Infineon's BTS3035TF) which seems to be a perfect match. Due to the lack of time I just soldered it on a prototype board.

I didn't want to use a second power supply for the small radar board (input voltage 1.5V-5V) so I also added one of the "commonly used" DCDC step down converters and adjusted the output voltage to 3.3V.

Unfortunately, the radar board shows a LOW signal on the TD pin when a motion is detected so I couldn't connect it directly to the smart switch. I used a small, low cost XMC microcontroller board, the XMC2Go to overcome this problem and added also a dimming function to my light when switching on and off. The Arduino code can be found below.

I just glued all PCBs together and ended with this setup:

1 / 2 • left: XMC2Go, right:DCDC, switch and radar

The housing

I also 3D printed a housing to mount the setup, protect it and fit a barrel connector to connect my 24V power supply.

1 / 2 • Housing inside

Can you spot the sensor?

One of the cool things about radar is that it can shoot through materials. This allowed me to mount the sensor on the backside of my wooden workbench shell - fancy, isn't it?

1 / 2 • Automated workbench lighting

BGT60 lighting

const int motion_state = 9;     // the number of the motion pin
const int ledPin =  8;      // the number of the LED pin
bool motion = 0;         // variable for reading the pushbutton status
int brightness = 0;

void setup() {
  pinMode(ledPin, OUTPUT);      // initialize the LED pin as an output
  pinMode(motion_state, INPUT); // initialize the motion pin as an input
}

void loop() {
  motion = digitalRead(motion_state);             //read the state of motion 
  if (motion == HIGH) {                           //no motion detected
    brightness = constrain(brightness - 1,0,255);   //reduce brightness
  } else {                                        //motion detected
    brightness = constrain(brightness + 2,0,255);   //increase brightness
  }
  analogWrite(ledPin, brightness);
}

Overengineering your workshop lighting

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

New sensor - new opportunity

Adding a power stage and DCDC converter

The housing

Can you spot the sensor?

Code

BGT60 lighting

Credits

Infineon Team

Comments

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Overengineering your workshop lighting

Overengineering your workshop lighting

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

New sensor - new opportunity

Adding a power stage and DCDC converter

The housing

Can you spot the sensor?

Code

BGT60 lighting

Credits

Infineon Team

Comments

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