App note from NXP Semiconductors dealing with oscillators in microcontrollers. Link here (PDF)
Most microcontrollers can use a crystal oscillator as their clock source. Other options include external canned oscillators, resonators, RC oscillators, and internal clocks. The main advantages of a crystal oscillator are frequency accuracy, stability, and low power consumption. However, high reliability is needed to fully benefit from these advantages.
Cell balancing implementation from NXP Semiconductors. Link here (PDF)
Batteries made of multiple cells connected in series are often used as a power source for common electronic devices. In multicell battery chains, small differences between the cells (due to production tolerances or operating conditions) tend to be magnified with each charge or discharge cycle. In these situations, weaker cells are overstressed during charging, causing them to become even weaker, until they eventually fail and cause a premature failure of the whole battery. Cell balancing is a way of compensating for these weaker cells by equalizing the charge on all the cells in the chain, thus extending the battery life.
A team of student designers and engineers from the RCA and Imperial College have developed a substitute for GPS that does not rely on satellites, called Aweigh:
Aweigh is an open navigation system that does not rely on satellites: it is inspired by the mapping of celestial bodies and the polarized vision of insects. Ancient seafarers and desert ants alike use universally accessible skylight to organize, orient, and place themselves in the world. Aweigh is a project that learns from the past and from the microscopic to re-position individuals in the contemporary technological landscape.
Via Open Electronics.
Check out the video after the break. Continue reading “Aweigh: the open-source alternative to GPS”
Every Tuesday we give away two coupons for the free PCB drawer via Twitter. This post was announced on Twitter, and in 24 hours we’ll send coupon codes to two random retweeters. Don’t forget there’s free PCBs three times a every week:
Some stuff:
We try to stagger free PCB posts so every time zone has a chance to participate, but the best way to see it first is to subscribe to the RSS feed, follow us on Twitter, or like us on Facebook.
Steve (VE7SL) has built a Jones Power-Oscillator using a pair of 6L6s and wrote a post on his blog detailing its assembly.
Glen has written an article detailing his homebrew DMX-controlled RGB LED light:
This project is a small DMX-512 controlled, color-changing RGB LED light. The light can be controlled via the DMX512 protocol or it can run a number of built-in programs depending on how the software is configured. The light incorporates an advanced 16-bit PIC24 microcontroller with PWM capabilities, a 3D printed enclosure, a laser cut acrylic lid, a custom switching power supply, and a MEMS oscillator. The light measures roughly 2.25″ square by 1.25″ high. This light is the evolution of my RGB LED light designs that span back over a decade.
Project info on Photons, Electrons, and Dirt blog.
Michael Krumpus designed and built an Arduino shield for Nimbelink Skywire CAT M1 and NB-IoT modems, that is available on Github:
Nimbelink has a development kit for use by product developers, but it’s rather expensive. I wanted to try out a Nimbelink CAT M1 modem without the dev kit, and since there are so many hobbyists using Arduinos out there, I wanted to provide a nice Arduino library for the modem. I chose the Nimbelink module based on the Sequans Monarch CAT M1 modem and got to work designing an Arduino shield to hold it.
More details on Nootropic design Project Lab site.
Another app note from ON Semiconductors on using PWM technique to reduce power consumed when latching mechanical relays. Link here (PDF)
Integrated circuit driver circuits often use relay loads in their application. Output drivers are a source of power dissipation on the IC. Latching relays can be used to keep sustaining load current at a minimum by engaging and removing drive current, but a PWM system can also preserve reduced power conditions by engaging and reducing duty cycle using standard type relays.
By considering the Maximum Turn−On Voltage and Minimum Turn−Off Voltage specifications typically quoted in the relay electrical specification, your system design can utilize a signal to pull−in and activate the relay followed by a reduced power PWM sustaining signal.
ecoSWITCH(TM) from ON Semiconductors offers space saving solution on power distribution system. Link here (PDF)
Load switches play an important part in the management of supply domains and the protection of the loads they supply. Loads switches are often used for power sequencing, standby load leakage reduction, and inrush current control. Integrated ecoSWITCH products deliver an area reducing solution, offering over current protection, load soft start, and extremely low on series resistances of sub − 20 milliohm. This article discusses the primary benefits of load switches, application considerations, and how ecoSWITCH differs from other types of integrated switch offerings. A generic cloud system application and USB power delivery example are presented to demonstrate how the addition of ecoSWITCH solves design challenges such as achieving low quiescent current, local load protection, and startup sequencing.
Glen Akins published a new build:
After using the PIC16F1459 to build numerous USB HID input devices including a giant keyboard, a tiny keyboard, and a big red button, it was time to see if the PIC16F1459 could be used to control outputs too. Sticking with the industrial theme, I chose to build a USB controller for a, um, stack of industrial stack lights.
See the full post on Photons, Electrons, and Dirt blog.
Here’s a tear down of a crystal oscillator and a look at the silicon controller from Electronupdate:
Inside is a ceramic circuit board. Ceramic has a low coefficient of thermal expansion which is probably very desirable here. It will also not absorb moisture. All of this would affect the frequency.
More details on Electronupdate blog.
Check out the video after the break. Continue reading “Crystal oscillator teardown”
Every Tuesday we give away two coupons for the free PCB drawer via Twitter. This post was announced on Twitter, and in 24 hours we’ll send coupon codes to two random retweeters. Don’t forget there’s free PCBs three times a every week:
Some stuff:
We try to stagger free PCB posts so every time zone has a chance to participate, but the best way to see it first is to subscribe to the RSS feed, follow us on Twitter, or like us on Facebook.
Here’s a cool WiFiChron clock with 8-character alphanumeric LED display by Florinc:
For WiFiChron, two cascaded modules make an 8-character display functionally similar to HDSP-2534, but bigger and more visible. With the “Display Abstraction Layer” already in place, software support should be easy to integrate, since controlling it with the HT16K33 breakout allows the re-use of the above mentioned Adafruit LED backpack library. For maximum compatibility, I followed the same wiring, then connected the two extra segments, A2 and D2, to pin 10 (not connected for the 14-segment backpack) and pin 11 (connected to the DP), respectively.
More details on Wise time with Arduino blog.
Würth Elektronik app note on EM radiation emission from power inductors. Link here (PDF)
DC-DC converters are widely used in power management applications and the inductor is one of the key components. The usual focus is on electrical performance characteristics such as RDC, RAC and core losses. But, the electro-magnetic radiation characteristics can often be overlooked.
Due to the switching action in SMPS, AC voltage/current is produced over the inductor. Since, an inductor can, in effect, operate as a transmitting loop antenna, the electromagnetic radiation depends on a number of factors. These include the source properties such as core material, shielding material and the orientation of the start of the winding amongst others.
Electromagnetic radiation of an inductor in the low frequency spectrum range (100 kHz to 30 MHz), which is caused by the switching frequency and harmonics, is dependent on whether the inductor is shielded and the winding properties. Whereas, in the high frequency spectrum range (30 MHz to 1 GHz), where emissions are caused by ringing frequencies and their harmonics, the electromagnetic radiation is more dependent on the shielding characteristics of the core material, switching frequency and transitions of the switching converter.
A great guide from TDK about power inductors used in DC-DC converters. Link here
As electronic devices become more advanced, the power supply voltage of LSIs used in them is lowered, so their power consumption can be reduced and their speed increased. However, a decrease in the power supply voltage also causes the requirements regarding voltage fluctuations to become more severe, creating a need for high-performance DC-DC converters to fulfill these characteristic requirements, and power inductors are important components that greatly affect their performance.
Frank documented a 3D printer build, called Hephaestus:
I finally did it, I designed and built my own 3D printer. This is in no way “the best 3D printer”. Instead, this was an epic and nightmare project that exercised my ability to engineer and build my own CNC machine. Along the way, I figured out what I did well and what I did badly, mistakes were made and sometimes fixed, even ignored.
You can find the build log on Eleccelerator project page.
Facelesstech published a new build:
I’ve been on a quest for while now trying to build a retropie handheld that was functional but didn’t break the bank. So far I’ve made ZeroBoy – A poor man’s retropie “portable” and a follow-up ZeroBoy rev C – An improved poor mans retropie portable. These were great but I think I have made a much better system with all the features included.
More details on Facelesstech blog.
Check out the video after the break. Continue reading “RetroZero (retropie handheld)”
Coilcraft’s app note on why inductor’s voltage ratings are uncommonly mentioned in most applications. Link here (PDF)
Voltage ratings are often specified for many electronic components, including capacitors, resistors and integrated circuits, but traditionally this has been rare for inductors. Recent trends, particularly the introduction of higher voltage rated semiconductor devices, have created a new emphasis on operating voltage as part of the inductor selection process. Inductors once considered optimized for high current, low voltage applications are finding homes in new designs that apply higher voltage stress to the inductor.
App note from Coilcraft camparing two recognized power supply topologies. Link here (PDF)
Beatles or Stones? Michael or LeBron? Deep dish or thin crust? Forward or flyback? These are just a few of the age-old questions that have been hotly debated over the years, people arguing their opinions with great vigor. But, the truth is, most of the time the answer is both, due to the merits of each.
In this article, we will focus on forward or flyback. We’ll discuss the characteristics of active clamp forward and continuous conduction flyback isolated power supply topologies and demonstrate the design and performance trade-offs of each using two telecom-oriented power supplies as examples.
A HX711 load cell library for AVR ATmega:
HX711 is a precision 24bit ADC IC designed for weigh scales and industrial control applications to interface directly with a bridge sensor.
A load cell is a transducer that is used to create an electrical signal whose magnitude is directly proportional to the force being measured.
The library you can find here is usefull to implement a weigh scale using the HX711.
More details on Davide Gironi’s blog.
Check out the video after the break. Continue reading “HX711 load cell amplifier library for AVR ATmega”
