Author Archives: R-B

MAX038 function generator

Milen posted this Instructable on the design of a MAX038 function generator that also implements an Atmega328 and an LCD to display the parameters.

Max038 function generator

Max038 function generator

The function generator is very useful tool for the electronics freaks. It is needed for tuning resonance circuits, testing audio and video equipment, designing of analog filters and for many other different purposes.

Today there are two main types of function generators ; digital, (DSP based, DDS…) which are more and more often used and analog, which were the origins.

Both types have their advantages and disadvantages. The digital generators can generate signals with very stable frequency, but they have problems with generating very pure sine signals (what is not problem for analog one). Also the mainly spread function generators based on DDS approach have not so big frequency generation range.

Since long time I wanted to design a useful function generator, which could somehow combine some of the advantages of both types (analog and digital) generators. I decided to base the design on the Maxim chip MAX038*

LED light dimmer using PIC16F1936

Lukas Fassler recently moved to a new apartment and he wanted to have a PWM LED light dimmer to control some of his 12V LED strips. When he didn’t find a ready-made one that would meet his requirements, he designed his own using the PIC16F1936 MCU. His PWM dimmer can handle 100W output power at 12V DC.

PWM dimmer for LED strips

PWM dimmer for LED strips

At the center of my design is a 8-bit PIC microcontroller, a PIC16F1936. There’s not much special about this particular model, it’s just a type I’ve used several times before and still had some on stock.

A LM2931 provides the PIC with 5 volts from the 12 volts input voltage. I use the LM2931 as my standard 5V regulator. It’s pin compatible with the legendary 7805 but survives input voltages in the range of -50 to +60 volts making it very robust against transients.

Microchip launches MPLAB XPRESS, a Free, Cloud-based Development Platform for PIC MCUs

Today, Microchip Technology Inc. has launched MPLAB Xpress, a cloud based development environment with the most popular features of the MPLAB X IDE.

MPLAB XPRESS

MPLAB XPRESS

Microchip Technology Inc. (NASDAQ: MCHP), a leading provider of microcontroller, mixed-signal, analog and Flash-IP solutions, today announced its MPLAB® Xpress Cloud-based Integrated Development Environment (IDE).  This online development platform is the easiest way to get started with PIC® microcontrollers (MCUs), with zero downloads, sign-in or setup needed to start designing.  Microchip’s free, cloud-based IDE brings the most popular features of the award-winning MPLAB X IDE to Internet-connected PCs, laptops or tablets.  MPLAB Xpress offers the industry’s most comprehensive feature set, including a library of Microchip-validated code examples, interface to MPLAB Code Configurator (MCC) 3.0 for GUI-based MCU peripheral setup and automatic code generation, integrated MPLAB XC compilers, support for programmer/debugger hardware, and 10 GB of secure online storage with a myMicrochip account.  Users can easily migrate their projects to the full, downloadable MPLAB X IDE.  Additionally, the MPLAB Xpress Community enables developers to share their code, design ideas and knowledge.

MPLAB Xpress can be accessed from anywhere in the world athttp://www.microchip.com/Xpress-021516a.

A free MPLAB Xpress Evaluation Board (limited quantities available) can be obtained by filling out the form at http://www.microchip.com/Xpress-021516a, or by visiting Microchip’s Embedded World booth (Hall 1: Booth 1-510).  A brief presentation is also available at http://www.microchip.com/Presentation-021516a.

Wireless storage with biometric protection

Nathan Spallone and Zhiyuan Teo from Cornell University designed a wireless storage with biometric protection as their final project for Bruce Land‘s ECE 4760 course. Their design uses a fingerprint scanner for authorization and an induction coil for wireless charging. The user can authenticate into the storage system by simply placing a thumb on the fingerprint sensor and can sync the drive to a home station wirelessly using an nRF24l01+ transceiver module. The home station also usesan nRF24l01+ transceiver module along with an Arduino board, which is connected to a PC over USB. They also wrote a PC application to allow the user to read and store data on the device over the RF link.

Wireless storage with biometric authentication

Wireless storage with biometric authentication

The base station also has an inductive charger that the user can place the device on to charge wirelessly, without the hassle of plugging anything in. 20 fingerprints can be stored on the device, and each fingerprint has a separate logical volume that the corresponding user can utilize as their own private storage space.

The device has a 1 inch OLED screen that gives the user feedback and information, such as which current user is logged in, and how much storage is being used.
he device is extremely usable. It does not require the nimble action of plugging in a device every time a user wants to manipulate a file, rather it can be activated wirelessly. As well, there are no buttons on the device except for a power switch, and the only actuation needed for operation is touching a finger to a fingerprint scanner. The OLED is monochromatic, thus anyone with any sort of colorblindness will be able to use the device.

Standalone LED tester

David Cook’s new handy LED tester is based on the LM317L adjustable current regulator and consists of a microcontroller and an LCD to display the forward bias voltage across the LED and required series resistance for operation at the user-specified current and circuit voltage.

DIY LED tester

DIY LED tester

Most projects include at least one LED. Before soldering the LED, how can you determine if the color and brightness meets your needs? After that, how do you calculate the correct value resistor?

Many years ago, I built a handy compact LED testing tool based on the LM317L adjustable current regulator. (You’ll definitely want to click on that link before continuing with this article.) It ended up being one of the most useful tools. In fact, the LED tester sits on a shelf above my keyboard, because I use the tester almost as often as I use my multimeter.

The problem with my original LED test tool is that I need a multimeter to measure the voltage of the LED. And, then I need a spreadsheet to calculate the resistance needed for that LED voltage with a given circuit voltage.

So, I decided to make an improved LED tester with LCD display!

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