Series-connected MOSFETs increase voltage & power handling


by Ilija Uzelac @

This Design Idea presents a simple, proven, reliable, and robust method for charging large capacitor banks, using a series connection of power MOSFETs to raise the breakdown voltage over that of an individual MOSFET.

When a power supply drives a large capacitive load, inrush current, if not limited, can reach tens or hundreds of amps for a high voltage power supply. In general, maximal ratings of a power supply could be transiently exceeded by many times, but this is generally acceptable when the transient lasts a few AC-line cycles. This is typical for load capacitances up to a couple of hundred microfarads, but for load capacitances in thousands of microfarads, an inrush current limiter is a must.

Series-connected MOSFETs increase voltage & power handling – [Link]

Cheap Arduino CNC


by siemenwauters @

this is my first instructable. i show you updates on my cnc machine which will cost about 200 euro’s for still decent quality.
don’t hate if you don’t like this instructable, I’m just an 18 years old student from belguim sharing his ideas and creations with other people. because i think working together and sharing idea’s will make better projects.

this is what the machine looks like right now. ill post new photos every time i advance building

i know my video’s are not the best. i’m working hard to show you how everything works so it would be nice if you watched at least a peace of all of them to support my project.

Cheap Arduino CNC – [Link]


96×48 full-color LED Matrix


A few years ago I built a red-only 32 pixels high, 96 pixels wide LED Matrix, and due to all the positive responses I sought out to do it again the year after with a bigger better matrix. I did some research into affordable solutions, and as usual ended up with Chinese vendors. I got my hands on about 10 32×16 RGB LED panels with a 1cm pixel pitch, and a HUB75 connection, quite similar to the ADAFruit 32×16 matrix. ADAFruit had a bunch of information on them, and there are several other places where they’re being used, so I figured I’d give it a shot. I even bought a Digilent Basys 2 FPGA development board, as these boards are apparently best driven by an FPGA, and I was willing to pick that up.

96×48 full-color LED Matrix – [Link]

Location based development board


Matt Coates of Sky Labs Electronics writes:

So here it is! Courtesy of Dangerous Prototypes Dirty PCB service, I have been able to put together and complete the testing of the first prototype of my very own location based development board. So lets talk about what you’re looking at. The board is a 4 layer PCB of dimensions 50 x 68 mm. The populated board has a maximum thickness of 9 mm. I considered using a 2 layer board, but the ground planes would not have been large enough and the substrate was too thick for the micro strip trace to the antenna to be of a realistic width. The microcontroller is running an Arduino Bootloader and the board is pictured on 7mm standoffs that are attached using M2 screws.

Location based development board – [Link]

Interfacing BMP180 temperature and pressure sensor on Arduino UNO


“Raz” over has written a tutorial on how to interface BMP180 temperature and barometric pressure sensor with Arduino UNO board. The BMP180 is a new generation sensor coming on a LGA package and it’s able to measure pressure in the range of 300 to 1100hPa using low power and achieving low noise measurements. The interface is a standard I2C and sensor is fully factory calibrated. The voltage required to power the IC is 3.3V, so your Arduino must provide 3.3V. On this tutorial the data is displayed on a 1.44″ TFT display and “Raz” moved a step further calculating the altitude from the derived pressure. Code and libraries are supplied on the link below.

Interfacing BMP180 temperature and pressure sensor on Arduino UNO – [Link]

Server response time meter



Been awhile since I posted anything here, so I thought I’d use this post to give some more detail on a project I just completed. The whole idea was to create a giant meter to show website response time almost like a speedometer would. The result is something that’s both fun to watch and provides a meaningful ‘heartbeat’ of current status. After several revisions and different designs along the way, I ended up with what you see here.

Server response time meter – [Link]

Ultra-low noise linear regulators for powering PLL/VCO and clocking ICs


by Maurice O’Brien @

Wideband communication systems usually require an ultra-low noise regulator to power the VCOs and PLLs. The regulator must also be able to reject any ripple presented at its input. In a typical system, an ac input is converted to an isolated dc supply rail, –48-V, for example. This rail is then converted to an isolated 12-V or 5-V system rail that powers the main components in the communication system.

Ultra-low noise linear regulators for powering PLL/VCO and clocking ICs – [Link]

Thermocouple Auto-Zeroed Reference Design


The MCP6V01 auto-zeroed op-amp features an ultra low offset voltage (VOS) and high common mode rejection ratio (CMRR), which makes it applicable to temperature measurement. The MCP6V01 thermocouple auto-zeroed reference design demonstrates how to measure electromotive force (EMF) voltage at the cold junction of the thermocouple in order to accurately measure temperature at the hot junction.

The difference amplifier is implemented using the MCP6V01 and 0.1% tolerance resistors. It amplifies the EMF voltage at the cold junction of the thermocouple. The MCP9800 senses temperature at the type K thermocouple’s connector. It should be located as close as possible to the connector on the PCB. This measurement is used to perform cold junction compensation for the thermocouple measurement. The MCP1541 provides a VREF (4.1V) to the internal 10-Bit ADC of the PIC18F2550 and sets the reference voltage for the difference amplifier. The CVREF is the internal comparator voltage reference of PIC18F2550, which is a 16-tap resistor ladder network that provides a selectable reference voltage. The MCP6001 buffer amplifier eliminates the voltage reference output impedance problem and produces the voltage VSHIFT.

The 2nd order RC low-pass filter that is implemented in this circuit can remove the high frequency noise and aliasing at the ADC input. The ADC of PIC18F2550 completes the analog-to-digital conversion. The data will be transferred to the PC using the USB interface. The thermal management software on PC is used to perform data display to show the real-time temperature and apply cold junction compensation and data linearization to determine the actual temperature of the thermocouple’s hot junction (weld bead).

Thermocouple Auto-Zeroed Reference Design – [Link]

Uncompromising quality audio connectors for a compromising price


Long term reliable contact without interference, creaking and hum, moreover in a beautiful coat – these are the Neutrik / Rean connectors.

Connectors have in general one interesting feature – there are many similar or almost the same connectors on the market. Audio connectors are not exception in this. Even though they look the same, many times there are huge differences in price and mainly in quality. If we supposed, that every producer designs and makes his products likewise responsibly, then the cheaper one should be probably a good choice. Naturally, in praxis it isn´t so.

A real difference between a quality and a low-class connector can be known only at a close-detail investigation and comparison, and ideally after a real testing in praxis.
Quality audio connector must be made of quality materials and also with a high precision. Naturally, if a producer wants to achieve success on a market, it´s often simply impossible to use a too expensive connector, which would over-price the whole device.

That´s why you can find in our store the Neutrik / Rean connectors offering a high-end class for a very reasonable price. Company Neutrik specializes already for almost 40 years in audio connectors and in general connectors for audio/ video studios, equipment of concerts (backstage) and similar, that´s why also in loudspeaker connectors, power supply, Ethernet,…
In the Neutrik products can also be found connectors Rean representing even more affordable price level while maintaining a very high quality. Already a short look at details of Neutrik/ Rean connectors will tell us, that we´re dealing with precision connectors. A matter of course is a detailed documentation with an exact description of electrical features and materials used. A comprehensive overview about available types will give you the Rean catalogue and the Neutrik catalogue (22MB). To many sophisticated connectors like for example NYS373 there are also available assembly instructions.

Uncompromising quality audio connectors for a compromising price – [Link]

Video generator with PIC.


by Beke András @

An black and white monitor needs to improve and repair from about 1990-th. The repair of device was not difficult but it caused troubles for the testing and setting of the monitor. We have a pattern TV generator, but this instrument are produce on the composite video signal for monitor. Unfortunately this monitor is demand not compozite signal instead of horizontal sync, vertical sync, and lightning signal. (video signal). Whereas the monitor host machine is not available – in fact I don”t know exactly what kind of equipment, perhaps a kind of mass spectrometer or something -, we need necessary a appropriate video signal source.

Video generator with PIC – [Link]