Tag Archives: PWM

Staff with Click Sound and Obstacle Alarm

People who are visually impaired usually use a staff to guide them as they walk. They tap with their staff to know if an obstacle is present around. Others use the echolocation technique. They produce a clicking sound through their tongue, foot, and fingers and through this they detect objects from their surrounding by sensing the echoes produced.

The design above is a simple project that aims to assist visually impaired persons by having a staff that produces a beep/click sound that they can use for echolocation and also has an ultrasonic sensor that alerts the user if there is an obstacle ahead. Inside the handle of the staff, the control circuit is located. Below it, the speaker is positioned facing front to release in a forward direction the beep/click sounds for the user to sense what is ahead. The speaker is connected to PWM pin of the microcontroller to produce sound. An ultrasonic sensor is located at the base of the staff. It is connected to an interrupt pin of the microcontroller. The continuous beep/click sound is replaced by an alarm sound when the sensor detects an obstacle. With this, additional aid is provided to the user especially to those who are not trained to be capable of echolocation. The base circuit and the control circuit in the handle are connected through the use of 179840-1 and 177900-4 Power Double Lock from TE Connectivity. These are headers and crimp housing connectors that provides durability to the design. The feature locking capability that secures the mating of the circuits connected together.

The design is operated with a +5V battery and has a switch to ON/OFF the circuit. The project is programmed to detect objects half meter and below. Beyond this range, the design will not alarm for the user to have a lesser restriction in moving. With this design, visually impaired users don’t have to tap their staff hard, which could hit someone or something.

Staff with Click Sound and Obstacle Alarm – [Link]

PWM Halogen Lamp Dimmer


High Current PWM Halogen Dimmer controller project is designed around SG3525 IC and High current MOSFET. Project can handle lamp up to 5 Amps (10Amps Possible with big heat sink) and supply 12-24V DC .Ideal for Halogen Dichroic Lamp or Halogen Lamp.


  • Supply input 15 to 24 VDC
  • Load-Lamp 12 to 24 VDC @ 5 Amps (10amps possible with big heat sink on Mosfet)
  • Onboard preset for frequency adjust
  • Frequency adjustable 4 KHz to 30 KHz
  • PWM Duty cycle 0 to 100% (+/- 5%)
  • Potentiometer for dimming adjust
  • Soft Start facility
  • Clamp diode for protection
  • Power-On LED indicator
  • Compact design and high quality
  • Lamp and supply connection via screw terminal connector
  • Four mounting holes of 3.2 mm each
  • PCB dimensions 56 mm x 42 mm

PWM Halogen Lamp Dimmer – [Link]

Simple Infrared PWM on Arduino, Part 3


The crew from AnalysIR has written up an article on Simple Infrared PWM on Arduino. If you missed part 1 and part 2, be sure to check it out.:

In Part 1 of this series, we demonstrated how to send signals using soft or Simple Infrared PWM on Arduino. In our Part 2 post we looked at sending RAW IR signals – specifically a RAW NEC signal and a longer RAW Mitsubishi Air Conditioner signal using soft PWM. We have since improved the PWM method shown in Part 1 & Part 2 to provide better performance and improve portability. In this Part 3, we will take the signals from Part 2 and show how to send them using their binary (or Hex) representation, which can save lots of SRAM in many projects, particularly when dealing with longer AC signals.

Simple Infrared PWM on Arduino, Part 3 – [Link]

50,000V High Voltage Power Supply


by Victor8o5 @ instructables.com:

This high voltage power supply has been designed to output a fixed voltage of around 50kV, it could easily be converted to an adjustable supply by connecting a variac in case of using transformers or by adding some extra circuitry to regulate the power going in. I initially thought about a high frequency PWM to regulate the power going into the capacitors, but I abandoned the idea. I found that adjusting the frequency is enough to make the voltage vary by a significant amount, allowing some control over it, this happens because the flyback must operate at a certain frequency in order to maximize the output.

50,000V High Voltage Power Supply – [Link]

UC3844 base motor speed controller


Dilshan Jayakody writes:

UC3844 is popular current mode controller which is commonly found on DC-to-DC converter circuits and switch mode power supplies. This motor speed controller is also based on UC3844 and it is specifically design to drive 20V – 24V DC motors.

In this given configuration UC3844 produces (approx.) 50kHz to 240kHz PWM output and this range can be adjust by changing the value of C2 timing capacitor. As per the datasheet UC3844 is capable to produce PWM output frequency up to 1MHz.

UC3844 base motor speed controller – [Link]

60V LED Driver with Internal 4A Switch & PWM Generator


The LT3952 is a current mode step-up DC/DC converter with an internal 60 V, 4 A DMOS power switch. It is specifically designed by Linear Technology to drive high power LEDs in multiple configurations. It combines input and output current regulation loops with output voltage regulation to operate as a flexible current/voltage source. The LT3952’s 3 V to 42 V input voltage range makes it ideal for a wide variety of applications, including automotive, industrial and architectural lighting.

60V LED Driver with Internal 4A Switch & PWM Generator – [Link]

Simple Infrared PWM on Arduino


by analysir.com:

We are often asked on discussion boards, about conflicts between IRremote or IRLib and other Arduino Libraries. In this post, we present a sketch for ‘Simple Infrared PWM on Arduino’. This is the first part in a 3 part series of posts. Part 1 shows how to generate the simple Infrared carrier frequency on Arduino, using any available IO pin and without conflicting with other libraries. Part 2 will show how to send a RAW infrared signal using this approach and Part 3 will show how to send a common NEC signal from the binary or HEX value.

Simple Infrared PWM on Arduino – [Link]

Power playground project


Spacewrench over at Dorkbotpdx published a new build, a Power Playground project:

It’s a PMOS/NMOS H-Bridge with FETs that can handle 3 amps or so, plus a SPI current sensor, some switches & a rotary encoder (not stuffed yet), and a 7-segment display, all controlled by a Teensy-3.1 running FreeRTOS.

I made this because I’m always running into battery, power, inductor and transformer issues I don’t have any experience with. The idea is to use the H-bridge configuration and current sensors to experiment with moderate-current PWM, motor control, power-line synchronization, battery charging and discharging, etc.


Power playground project – [Link]