Electronics-Lab.com Blog

An app note on a LED brightness controller:

In this circuit, a digital potentiometer (DS1869) aids an LED-driver IC (MAX16800) in providing manual control of the LED brightness. The circuit also provides thermal protection against excessive heat and overload conditions.

LED brightness controller with 64 taps - [Link]

Chris from PyroElectro has posted his plans for a 10-A H-Bridge motor controller that avoids using the the typical controller ICs. He writes:

Motor control is the core heart of robotics. Without locomotion or any movement a robot is dull and lifeless. The H-bridge is a tried and true concept for DC motor control. It allows you to move motors forward, backward and with varying speeds through PWM (pulse with modulation).

This tutorial will take a few steps back from the all-in-one L298 or LMD18245 motor control ICs and look more into how we can build our own H-bridge without the need of an IC.

10-A H-Bridge motor controller - [Link]

KTechlab is an open source IDE for microcontrollers and electronics design and works with Linux systems. It includes a simulator for analog and digital circuits and incorporates a C compiler. [via]

KTechlab IDE for microcontrollers and electronics - [Link]

openpicus.blogspot.com writes:

Internet of things becomes more and more interesting. But what does Internet of Things really mean? The answer is simple: more connected devices such ad TV, DVD playes, cars and, of course, smartphones and tablets.

With Flyport, Internet of Things is more closer to you! Why?! Well, because, with Flyport, the wifi programmable module, you can now interface to the cloud services – ThingSpeak.

ThiDIY gives access to the ThingSpeak Services. ThingSpeak allows to draw online charts, to store and recall values and to use specific APIs to work with Twitter, or to send HTTP requests directly from the ThingSpeak servers.You can create private or public channels. Every channel can store up to 8 fields (the values) and creates charts with those fields. Every channel has a “Channel ID”, a “Name”, a “Write API Key” and a “Description”. The Write API Key is the most important information of the channel, since it allows to upload or download the field data.We created a public channel to share with you the results of this Application. You can also use the private channels to respect the user privac
This DIY gives access to the ThingSpeak Services. ThingSpeak allows to draw online charts, to store and recall values and to use specific APIs to work with Twitter, or to send HTTP requests directly from the ThingSpeak servers.

You can create private or public channels. Every channel can store up to 8 fields (the values) and creates charts with those fields. Every channel has a “Channel ID”, a “Name”, a “Write API Key” and a “Description”. The Write API Key is the most important information of the channel, since it allows to upload or download the field data.

We created a public channel to share with you the results of this Application. You can also use the private channels to respect the user privacy.

You can download for free the Application Note to interface by yourself Flyport to cloud service

How to interface Flyport to cloud services - [Link]

Pittsford, NY: Saelig Co. Inc. announces the availability of the EPIC Sensor (Electric Potential Integrated Circuit) – a new, innovative and disruptive electric field sensor. This completely new sensor technology measures electric field changes without requiring physical or resistive contact. EPIC is an award winning, patent-protected sensor that can rapidly measure electric potential sources such as electrophysiological signals or spatial electric fields.

The EPIC Sensor will revolutionize the way medical ECG/EEG/EOG, movement sensing, proximity non-touch switching, or even gesture recognition signals are taken in medical and sports instruments, toys, electric appliances, smart lighting, gaming, and security.  The electrode surface of the detector is coated with a passivated thin dielectric for direct application to a test surface (such as human skin) without the need for electrically conductive gel. It can be used as a dry contact ECG sensor without the need for potentially dangerous low impedance circuits across the heart.   By detecting changes in the electric field, the EPIC sensor can also drive a relay to act as a simple non-touch electric switch. The EPIC sensor can be employed in a proximity mode or to detect specific kinds of movement as a gesture recognition device. As the EPIC sensor does not need line of sight, it can even detect movement through solid walls, and can also be used to replace, or as an adjunct to, passive infra-red (PIR) sensors in a variety of applications including security motion detectors. Read the rest of this entry »

ISS tracking theme clock face – Monochron Clock Kit. SPACECHRON, Scott writes – [via]

Some of my christmas money went towards purchasing a Monochron Clock kit from Adafruit.com.

It turned out to be an awesome build and I had lots of fun putting it together. I also chose it because it allows you to program your own clock “faces” for it. I’ve programmed a Space themed face for it that simulates the space station ground track. I’ve also programmed an autodim feature for the backlight because my preferred daylight brightness was too bright at night. The fact that I can customize it to fit my needs is an awesome thing. I wish there were more products like it.

ISS tracking theme clock face – Monochron Clock Kit - [Link]

unusualelectronics.co.uk writes:

I needed to replace two old, unreliable thermostats for controlling the heating and cooling for a large garden shed.
Commercial basic digital thermostats are available quite cheaply, but some lack the ability to control heavy loads or have the extra features that I require for saving energy when the door is often left open or to indicate temperature being out of range etc.

I like the PIC18F1320 microcontroller used in my previous project – so decided to use it again in a very similar design to drive three multiplexed LED displays and read the temperature from a Dallas/Maxim DS18x20 “1-Wire” digital sensor.

Digital Thermostat with LED Temperature Display - [Link]

Giorgos Lazaridis writes:

If you have work with some kind of industrial or marine automation, then most probably you’ve heard before the term PID. PID controllers are very common in closed-loop systems today. Here is how this system can calculate and minimize the error with great precision. 

The whole story began as a marine application, when people were trying to find ways to make reliable and accurate ship steering systems. But the problem was that, if the automation turns the rudder let’s say left, the ship will not turn instantaneously, instead it needs a long course, for ships do not steer like like cars, instead they have a big hysteresis. Another problem is also that when the ship finally turns to the right direction and the automation turns the rudder straight, the ship keeps turning left due to inertia and many other parameters like waves, wind, speed etc.

At first, proportional systems were developed to do this. A proportional systems reads the feedback (electronic compass) and turns the rudder according to the angle that the ship needs to turn. If for example the ship had to turn 45 degrees left, the rudder would turn 20 degrees, and as the ship slowly turns to this direction, the rudder decreases its angle proportionally. But this system has a great disadvantage: Either the rudder will oscillate left and right because the ship will never stay on course precisely due to external disturbances, or the system will stabilize with a small constant error in angle.

PID Theory - [Link]

Giorgos Lazaridis writes:

An AC Hum touch sensor is a very special technique, rarely used for switching applications, because it has a great disadvantage. In order to operate normally, an active AC power line has to be near by. More info about this type of touch sensor, along with other types (including the capacitance method), can be found in the corresponding theory page, how the touch buttons work..

DIY AC Hum Touch Button - [Link]

Giorgos Lazaridis writes:

Soldering stations comes in a variety of prices and capabilities. The cheaper stations have a power controller, to control the power delivered to the soldering iron. More expensive stations will have a temperature controller near the tip of the soldering iron, and control the temperature using this feedback.

The quality of soldering with a station is much higher than with a simple soldering iron. Especially if the station has a temperature controller on the tip. That is because, the solder has a very specific working temperature. For example, the one i use (60% tin 40% lead), is liquefied at 190C. Of course, you do not solder at 190C! The soldering iron i use, exceeds by far this temperature. I measured it up to 410C! This has negative effect on the soldering quality.

Homemade Soldering Station - [Link]