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  • Author Author: tariq.ahmad
  • Date Created: Date Created
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Enhancing a Magnifying Headband with Auto Sensing Light -- Episode 585

Do you often use a illuminated magnification headband? Do you get annoyed that you need to turn it off and on when looking away from your work? This project contains 2 solutions, a basic tilt sensor option that can be added in minutes, and a more complex distance detecting circuit which will change the illumination depending on how far away the object you are looking at is.

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Bill of Material:

Product Name Manufacturer Quantity Buy Kit
LC1780USB Magnifier, Spectacles & Headband, 1x, 1.5x, 2x, 2.5x & 3.5x LIGHTCRAFT 1 Buy Now
102010328 Arduino Microcontroller Board, SAMD21G18, ARM Cortex-M0+ SEEED STUDIO 1 Buy Now
STMICROELECTRONICS Daughter Board, VL53L0X Gesture and Ranging Sensor, FlightSense STMICROELECTRONICS 1 Buy Now
MICROCHIP Power MOSFET, N Channel, 60 V, 200 mA, 5 ohm, TO-92, Through Hole MICROCHIP 1 Buy Now
COMUS (ASSEMTECH) Tilt Switch, 15 °, 60 Vac, 0.25 A, Nickel COMUS (ASSEMTECH) 1 Buy Now
 

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  • Could be power or it could be software.

    You can check if it is the latter with the following code which should turn the LEDs on for 5s then off for 5s. If you still get flickering then it's probably not to do with your code.

     unsigned long time;

    bool led = 0;

    void setup() {
    pinMode(ledPin, OUTPUT);
    digitalWrite(ledPin, LOW);

    if (!lox.begin()) {
    while(1);
       }

    time = millis();
    }

    void loop() {
    VL53L0X_RangingMeasurementData_t measure;

    lox.rangingTest(&measure, false); // pass in 'true' to get debug data printout!

    if (measure.RangeStatus != 4) { // phase failures have incorrect data
    distance = measure.RangeMilliMeter;
    }

    if (millis() - time > 5000) {
          led = !led;
          digitalWrite(ledPin, led);
          time = millis()

    }

    delay(100);

    There's also a different example you can base your solution on which is the continuous scan. 

    https://github.com/adafruit/Adafruit_VL53L0X/blob/master/examples/vl53l0x_continuous/vl53l0x_continuous.ino


    You mentioned a blob chip on the visor. We can speculate what this might do, it could be something like an LED driver or perhaps something that does an auto power off? It might also be a voltage booster depending on how the LEDs are being driven.
    Obvious thing is to try and bypass that and drive the LEDs yourself. You've got a microcontroller there so you could use an PWM output to drive your FED instead of a simple digital one.






    github.com/.../vl53l0x_continuous.ino

  • in reply to Workshopshed

    I'd tested the software and it isn't that, but seemed the likely cause to begin with. Powering from USB it works perfectly, removing the switch with the "blob" which appears to be a switch IC with power off timeout also fixes it. So it seems the cause is that blob type circuit, which is a pain, as the moulded switch would have been nice to keep, and the auto timeoff is a nice feature

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  • in reply to Workshopshed

    I'd tested the software and it isn't that, but seemed the likely cause to begin with. Powering from USB it works perfectly, removing the switch with the "blob" which appears to be a switch IC with power off timeout also fixes it. So it seems the cause is that blob type circuit, which is a pain, as the moulded switch would have been nice to keep, and the auto timeoff is a nice feature

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