• Ultrasonic Lighting

    10/09/2020 at 02:22 0 comments

    This article shows an ultrasonic lighting system:

    You can see my circuit working in this video:

    I created this circuit after reading those articles:

    https://www.instructables.com/Transistor-Sensor-Amplifier/

    https://www.instructables.com/Ultrasonic-Alien/

    https://www.instructables.com/Sound-Light-Robot/



    Step 1: Design the Circuit

    I drawn the circuit in the old PSpice simulation software to reduce drawing and simulation time.

    The Rv potentiometer controls the brightness of the bright LED. The LEDs that I used in my circuit might need no more than 5 mA current. A typical LEDs consumes a current of 10 mA and have potential voltage of 2 V across its terminals. High currents might burn the LEDs or reduce the LED lifetime.

    Although microphone circuits are always biased, most ultrasonic circuits do not bias the ultrasonic sensor. In my circuit the DC current across the sensor is very small.

    The Ri1 resistor is needed because the potential voltage across the ultrasonic sensor could be very small due to low resistance/impedance. The Ri2 resistor is not needed. I connected this resistor to change the circuit characteristic. The LEDs turn OFF when the ultrasonic signal is applied. You can connect the circuit shown in this link: (https://www.instructables.com/Transistor-Sensor-Amplifier) that is almost similar to my circuit.

    All other information on circuit design is included in the Instructables links above.

    The Instructables links above included RC (resistor capacitor ) power suplpy filters. you might need those filters if your circuit is oscillating.



    Step 2: Simulations

    Simulations show that my design is correct:

    Time Domain:

    Output Current:

    Frequency Spectrum:



    Step 3: Make the Circuit

    You do not need to use the high power resistors that I used. I used 1 Watt resistors. You can use 1/4 Watt resistors. However, you got to admit that the circuit appears more professional with bigger resistors.

  • Potatoes and Eggs

    08/20/2020 at 12:13 0 comments

    I made a dish from:

    - baked potatoes,

    - baked onions,

    - and boiled eggs.

    You can see the photo here:

    Tastes great!

  • LED Bus

    04/20/2020 at 03:18 0 comments

    The article presented shows an LED Bus sculpture. 

    The wiring is a simple pair of bright LEDs connected in series with a button and a 3 V power source. 

    I thought of this idea when I received a solar USB charger kit from China. There were missing parts and I could not complete the kit. Thus I decided the use the kit just for the parts.

    One of those parts was a bright LED component. Usually a LED needs no more and no less than 2 V. However, the bright LED source from the kit seemed to dim even at 2.5 V. This is why I increased the power supply to 3 V (such voltage would burn a typical bright LED).

    You can see my sculpture working in this video:



    Step 1: Make the Bus

    I made the bus from packaging foam, masking tape, high power wires and metal pipes.


    My hobby solder would not stick to the bright LED PCB (Printed Circuit Board) inputs. Thus I soldered the wires directly to LEDs. You can see the plus sign on the left contact of the right LED.

    I used pliers to cut the high power wire and hack saw to cut the pipe in half for the wheels.


    Step 2: Make the Button

    I made the button from an old AFL (Australian Football League) official merchandise figurine spring.



    Step 3: Attach Light Covers

    I attached light covers with blue tack. The light covers were included in the solar USB charger kit.



    Step 4: Testing

    At fight the LED source was not ON. Thus I switched the polarity of the wires.

    You can see my LED bus working at night in this video: