Accurately simulate an LED


Jon Roman and Donald Schelle have a design idea on how to simulate a high power led to test your driver circuit.

Testing the driver circuit using LEDs, although easy, yields only typical results because the tests don’t factor in worst-case LED parameters and often generate undesirable light and heat during driver debugging. Although using a constant resistance might seem to be an appropriate approach, a resistor approximates an LED load at only one point on the current/voltage curve. An electronic load may prove to be a more useful approach. The control loops of the driver circuit and the electronic load, however, often result in system instability and oscillations.

Accurately simulate an LED – [Link]

Adjustable HV Power Supply for Stompbox


This SMPS can be powered with low input voltage, from 5 VDC to 15 VDC and provided adjustable Output Voltage: + 92 Vdc to +340 Vdc.

Can be used too, as power supply, for the Xenon Lamp, Nixie tube Clock, VFD display, Magic Eye, Neon, and too many others electronics circuits who need HV power supply to work. Is great to use with many models of Nixie tube. It can drive 6 Nixie tubes, in multiplex mode, from 180 to 200V. Powered with low voltage from 5VDC to 15 VDC. With this SMPS you can power 250V @ current of 7.5mA! *In all case above, important note, DC and AC filters must be improved, if is desired reducing present HF frequency noises at output! Another fact, informed before, the RF energy is irradiated as magnetic and electric field, shielded assembly could be necessary!

Adjustable HV Power Supply for Stompbox – [Link]

Send and Receive SMS with GSM SIM900 Arduino Shield


In this Instructable, you will learn how easy it is to send and receive SMS messages over GSM with Arduino.

One of the essential elements of building IoT project is the ability to connect devices. Wi-Fi and Bluetooth are good low cost choices, but they work only at close ranges, or in hotspot areas. When the device needs to be at a remote location GSM is a good and easy to setup option.

Send and Receive SMS with GSM SIM900 Arduino Shield – [Link]

How to Interface Stepper Motor With Arduino


This tutorial is going to teach you some basics on using Stepper Motor while interfacing with Arduino and Stepper Motor Driver.

Bipolar Stepper Motor is DC motor that move in discrete steps. It has multiple coils that are organized in groups called “phases”. By energizing each phase in sequence, the motor will rotate, a step at a time. In order to be able to move the motor, you will need a motor driver. Thus, stepper motor driver A4988 is designed to play this role. A4988 stepper motor driver comes with heat sink. This stepper motor driver lets you control one bipolar stepper motor at up to 2 A output current per coil.

How to Interface Stepper Motor With Arduino – [Link]

ESP8266 temperature logger


A ESP8266 temperature logger project from Facelesstech:

I decided to use the esp-01 module because I only need 2 GPIO pins since I was using the DS18B20 temp sensor and the WS2812 LED. This made the hardware really cheap and easy to reproduce too. I normally use FTDI boards when it comes to the USB to serial on my projects but I couldn’t find a FTDI board with micro USB that didn’t cost the earth. That’s why I went with the CP2102 which I hadn’t used before.
I think what really made me feel good about this project was the fact that I came up with the idea to use a Full sided male USB port for power teamed with a AMS1117 3.3v voltage regulator. This would allow me to just plug this straight into a USB wall wart or a phone charger battery bank.

ESP8266 temperature logger – [Link]

Iterated-map circuit creates chaos

DI5518f1Lars Keuninckx @ writes:

The Design Idea circuit shown below is a simple implementation of an iterated unimodal map, reminiscent of the logistic or Verhulst map encountered in the study of nonlinear dynamics. It is useful to show chaotic discrete-time dynamics to students, or as a random number generator. Specifically, the circuit implements: Vk+1 = rF(Vk), where F is a nonlinear unimodal function (a “bump”), implemented by the circuit in the dashed box. The response of this circuit is shown in the Vout vs. Vin plot.

Iterated-map circuit creates chaos – [Link]

Make Your Own Smartwatch From An Old Cell Phone


Have an old cell phone laying around? Don’t know what to do with it? What if I told you that you could turn that old cell phone into a smartwatch!

What I’d like to do for this crazy/ambitions project is turn an old cell phone into a smartwatch. So obviously an old cell phone is required. The primary reason for this project is simply that I had an old cell phone laying around and wanted to find a creative way to repurpose it. The one I had is a Nokia 1100, but most other old cell phones would work, so long as you can find the schematics for the LCD online

Make Your Own Smartwatch From An Old Cell Phone – [Link]

New PIC32MM family consumes as little as 500 nA

by Clemens Valens @

The new PIC32MM family, currently Microchip’s lowest power 32-bit PIC32 family, features sleep modes down to as little as 500 nA. Filling the gap between the PIC24F XLP and PIC32MX families, the new family also offers so-called core independent peripherals that once initialized can function without intervention of or loading the MCU core.

New PIC32MM consumes as little as 500 nA – [Link]

Hall-effect current sensing replaces shunt-resistive measurements

These high speed isolated calibrated current sensors are presented as an effective alternative to conventional shunt based solutions; standard-footprint packaged ICs simultaneously offer 100 kHz bandwidth, high accuracy and crosstalk resilience. By Graham Prophet @

Melexis (Tessenderlo, Belgium) has added the MLX91210 family of integrated sensors; operating from a 5V supply, the ICs have current sensitivity levels down to 26.7 mV/A and support linear current measurement ranges that span as far as ±75A corresponding to 30 ARMS current. Available in SO8 and SO16 package formats, these fully integrated Hall-effect current sensors have extremely low resistive curent-path losses (0.8 mΩ for the SO8 and 0.7 mΩ for the SO16) and provide high voltage isolation ratings (2.1 kVRMS and 2.5 kVRMS respectively), as well as accelerated responsiveness (within 5 µsec). The sensor output of each IC is factory-calibrated for a specific current range and compensated for optimal stability in relation to temperature and over the course of its working lifespan, so that long term accuracy is maintained.

Hall-effect current sensing replaces shunt-resistive measurements – [Link]

How To Select an Inductor


Sanket Gupta pointed us to his latest article, on how to select an inductor and discuss about the various types of them.

Inductors are two-terminal components used for filtering, timing and power electronics applications. They store energy in the form of magnetic fields as long as a current is flowing. Inductors oppose a change in current by inducing an electromotive force (or e.m.f) according to Lenz’s Law. The inductor can be approximated as an open circuit for AC signals and as a short circuit for DC signals.  The unit of inductance is Henry (H) .  

How To Select an Inductor – [Link]