It´s surely not necessary to remind that any device can fail. Failure of a component, overload of a component (underestimated sizing), external influence and many other reasons are daily causing failures of devices. If the result of a malfunction is only an intermediate shutdown, it´s let´s say a better case. But if a device malfunction could cause further damage or even fire, it´s surely worth to make everything possible to prevent it.
A typical component used as a complementary – independent protection from overheating is a thermal fuse. It is a cheap but very useful component, which opens (disconnects) a circuit after exceeding certain temperature. It is a “one shot” component, i.e. after its activation it remains open and the fused circuit is disconnected (the fuse must be exchanged). It´s suitable to choose such fusing temperature of the fuse, as we consider to be really faulty, which otherwise can´t occur in an ordinary operation. Production processes enable to produce thermal fuses in a wide range of temperatures and so fuses Microtemp from company Thermodisc, which we keep in stock, are available in a range of 72-257°C (opening temperature). It´s a really wide range enabling to use a fuse for example for fusing of other component (for example a thermal fuse thermally joined with a transistor heatsink) but also for guarding an air temperature inside a device. These fuses operate on a principle of melting a small plastic pellet inside a fuse, what will cause release of a spring and a consequent disconnection of contacts.
A substantial advantage of thermal fuses Thermodisc is a maximum current up to 10-25A/250VAC depending on a type. On stock we keep the G4 series with a max. current of 10A/250VAC. Small dimensions enable to use a component similarly like any ordinary component. It´s only necessary to be careful at assembling (overheating) especially at low-temperature types.
Details regarding a correct assembly as well as an overview and tips for a correct use of thermal fuses can be find in the Thermodisc application guide. Thermal fuses are also available in other packages, or also with tabs (Fast-in). Finally, we can mention, that to reach the highest protection level in critical application, it´s ideal to incorporate several types with a slightly different fusing temperature in series.
They act only ones – right then, when it´s really necessary… – [Link]
With the rapid development of GPS (Global Positioning System) techniques, GPS gets wider application in many fields. GPS has features such as high precision, global coverage, convenience, high quality, and low cost. Recently, the use of GPS extends speedily from military to civilian applications such as automobile navigation systems which combine the GPS system, e-map, and wireless network. GPS is getting popular, and the market for GPS techniques is extending continuously.
UARTs provide serial asynchronous receive data synchronization, parallel-to-serial and serial-to-parallel data conversion for both the transmitter and receiver sections. These functions are necessary for converting the serial data stream into parallel data that is required with digital systems. Synchronization for the serial data stream is accomplished by adding start and stop bits to the transmit data to form a data character. Data integrity is ensured by attaching a parity bit to the data character. The parity bit is checked by the receiver for any transmission bit errors.
The circuit describes how to combine GPS into a navigation system by using a Philips 2-channel UART, the SC16C2552B. The SC16C2552B is a two channel Universal Asynchronous Receiver and Transmitter (UART) used for serial data communications. Its principal function is to convert parallel data into serial data, and vice versa. The UART can handle serial data rates up to 5 Mbit/s.
- SC16C2552BIA44 Dual UART, 5 Mbps (max.), with 16-byte FIFOs
- 80C51 CMOS 0 to 42 MHz Single-Chip 8 Bit Microcontroller
- 12 MHz Oscillator Clock
- 1.8432 MHz Oscillator Clock
- 22pF Capacitor – 2 Units
- 33pF Capacitor – 2 Units
- 0.1µF Capacitor – 2 Units
- 10 µF Capacitor – 2 Units
- 74LV04 Hex Inverter – 2 Units
UART in GPS navigation system – [Link]
Dave looks at the open source hardware UFactory uARM 4-axis desktop robotic arm kit project available on kickstarter.
This is the first unit produced, and comes with the suction cup head and Arduino Uno board and shield controller.
EEVblog #586 – Open Source Hardware uARM 4-Axis Desktop Robotic Arm Kickstarter - [Link]
This project is a temperature controller for a PC FAN. It regulates the speed of the FAN attached to it according to measured temperature. Temperature is sensed using a simple NTC thermistor.
In most PCs the fan runs constantly, which may not be necessary. A simple circuit can regulate the fan speed according to temperature. This not only saves energy, it also reduces fan noise. Only three components are needed to allow the fan speed to be controlled according to the actual temperature: one adjustable voltage regulator (LM317T) and two resistors that form a voltage divider. One of the resistors is a NTC thermistor (temperature-sensitive resistor), while the other is a normal resistor.
Temperature Controlled PC FAN - [Link]
Andrea Biffi build a nice vertical nixie clock using ATmega8 mcu. He writes:
After the success of my first nixie clock made out from a rosewood block, I decided to lose no time and to carry on with the next one. As some of you guys already know, or imagine, lately I’m indeed a little bit addicted to nixie-mania. I’ve bought many nixie tubes on eBay, and I experienced in electronics so to build my own high voltage power supply and then the ultimate nixie clock circuit. Digits for this clock are nice rounded and fully transparent IN-4 tubes, the same I used in the first model, but as I previously announced, I aligned them vertically, so to read from top to bottom hours, minutes, and seconds. Indeed you will see the undeniable influence of Max Pierson’s vertical clock. I guide you now through the full process to make your own unique nixie clock.
Vintage style nixie wall clock - [Link]
Audigi @ instructables.com show us how to use an Arduino board to burn Arduino bootloader to mcus on a breadboard. He writes:
Connect Arduino Uno board to your computer. Start Arduino program and from examples choose “ArduinoISP” sketch and upload it to “Arduino Uno” board. Please make sure you select the correct board name and serial port. Now this board is ready to program new Atmega-328 chips on the breadboard as shown in the next step.
Burn Arduino Bootloader on Atmega-328 TQFP and DIP chips on Breadboard - [Link]
A team of scientists from the University of York, the Helmholtz-Zentrum Berlin (HZB) Germany, and Radboud University Nijmegen, the Netherlands, have developed a new class of magnetic material which flips magnetic state when zapped by an ultra fast laser pulse. This should pave the way to mass storage devices with improved performance and power efficiency compared to current day technology.
The new material demonstrates the use of a synthetic ferrimagnet comprising a sandwich of two ferromagnetic materials and a non-magnetic spacer layer. The spacer layer engineers the coupling between the two ferromagnets so that they align opposite one another. When subjected to an ultrafast laser pulse, this structure spontaneously switches its magnetic state representing writing a single bit of data. [via]
A New Class of Magnetic Material - [Link]
High efficiency, low standby power consumption and a power reserve, all this can be gained with a new adapter from our portfolio.
Minwa NR120P150PGS/E+ is in fact an “ordinary“ adapter with a fixed output voltage 12VDC/1500 mA. But it´s worth to mention, that it meets everything, what we usually require from a modern mains adapter:
- modern design (SMPS)
- high efficiency
- low standby power consumption (<0.3W)
- meets all latest regulations – EuP2, ErP,…
And finally a bonus – outstanding price. Adapters from company Minwa are in general always price-affordable, but here it is even more obvious. When we compare a one level weaker adapter NK120P100PGS/E+ (12V/1000 mA) with NR120P150PGS/E+ we´ll find, that for the price higher +14 (already at purchase of one piece) we´ll gain +50% power. So if you have a device requiring up to 1.5A current, or you use a 1A adapter at almost 100% and you want to gain some power reserve and probably a longer lifetime of an adapter, you can do so with minimum expenses.
Plus 50% of power for a scant one Euro? - [Link]
The Si7005 is a digital relative humidity and temperature sensor from Silicon Labs. It integrates fully factory-calibrated humidity and temperature sensor elements with an analog to digital converter, signal processing and an I2C host interface in a single monolithic CMOS sensor IC. The Si7005 is available in a “non hand-assembly-friendly” 4×4 mm QFN package, which requires reflow soldering to mount it on a PCB
Breakout module for Si7005 temperature and humidity sensor - [Link]
This tutorial discusses some general rules of thumb that make it easy to understand and analyze the operation of most opamp circuits. It presents some ideal properties of opamps, and discusses how negative feedback generally causes the input voltage difference to be equal to zero (input voltages are made equal by the action of negative feedback). In other words, the output will do whatever it can to make the input voltages equal. Applying this simple fact makes it easy to analyze most opamp circuits.
Basics of Opamp circuits – a tutorial on how to understand most opamp circuits - [Link]