DS3232 clock frequency calibration

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Kerry Wong writes:

DS3232 is an extremely accurate RTC with a guaranteed accuracy of 2.5 ppm (0 °C to 40 °C), which translates into an error of just 80 seconds over the course of a year under the worst case scenario. I had done a few projects using this chip before (you can read about them here).
While by default DS3232 is already very accurate, we can push its accuracy even higher by adjusting its aging offset register (8bit). This adjustment works by adding or subtracting the corresponding capacitance to or from the oscillator capacitor array. The adjustable range is represented as 2′s complement (-128 to 127) and each LSB change corresponds to roughly 0.1 ppm of change in frequency. So the overall adjustment range can be achieved programmatically is roughly ±13 ppm.

Check out the video after the break. Continue reading “DS3232 clock frequency calibration”

PIC-18 Breakout with ICSP

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A breakout for 18 pins DIP package Microchip PICs by Electropepper, he writes:

I needed to make a small test on some old chips i had, so i came up with a quick hour and half, break-out board for most PICs DIP-18 sockets. I also included an ICSP header.
I have been using this mostly to PIC16F88 and PIC16F628a, and it should be compatible with most 18 pins 16f family of microchip PIC microcontrollers.

 

 

Bus Pirate v3.8 free PCB build

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@psmay tweeted picture of his free Bus Pirate v3.8 PCB build:

If you build a free PCB we’ll send you another one! Blog about it, post a picture on Flicker, whatever – we’ll send you a coupon code for the free PCB drawer.

Get your own handy Bus Pirate for $30, including world-wide shipping. Also available from our friendly distributors.

Flux capacitor – Back to the future

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n1cod3mus made this flux capacitor from Back To The Future.  He writes a complete step-by-step guide on the Instructables site:

Since the release of the film back in the 80s I have been obsessed by the film Back To The Future watching the trilogy repeatedly. I watched it at the cinema over and over, I was very lucky that my great uncle was a projectionist so I could just sit in show after show.
So about 10 years back I decided I wanted to build a flux capacitor, but I got stuck back then because I didn’t have the correct skills at that time and I was making a mess of it, so I shelved the project.
I decided to come back to it with my now improved skills and technology, and this time I have something awesome!!

Check out the video after the break. Continue reading “Flux capacitor – Back to the future”

LM386 low voltage audio power amplifier

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Zx Lee published a low voltage audio amplifier build:

Today, I am going to share on how you can make a low voltage audio amplifier. For this project, I am using LM 386 Audio Amplifier, which is commonly used among electronics hobbyist. I will break the article into a few sections. First, I will explain about the LM 386 chip itself. Then move on with some explanation on the parts used in this project. And finally, the design of audio amplifier.

Check out the video after the break.

Continue reading “LM386 low voltage audio power amplifier”

App note: Hiccup-mode current limiting

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This is fairly old but interesting over current protection using Hiccup-mode from Microsemi. PDF here.

Hiccup-mode is a method of operation in a power supply whose purpose is to protect the power supply from being damaged during an over-current fault condition. It also enables the power supply to restart when the fault is removed. There are other ways of protecting the power supply when it is over-loaded, such as the maximum current limiting or current foldback methods.
One of the problems resulting from over current is that excessive heat may be generated in power devices, especially MOSFET’s and Schottky diodes and the temperature of those devices may exceed their specified limits. A protection mechanism has to be used to prevent those power devices from being damaged.

Free PCB Sunday: Pick your PCB

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We go through a lot of prototype PCBs, and end up with lots of extras that we’ll never use. Every Sunday we give away a few PCBs from one of our past or future projects, or a related prototype. Our PCBs are made through Seeed Studio’s Fusion board service. This week two random commenters will get a coupon code for the free PCB drawer tomorrow morning. Pick your own PCB. You get unlimited free PCBs now – finish one and we’ll send you another! Don’t forget there’s free PCBs three times every week:

Continue reading “Free PCB Sunday: Pick your PCB”

App note: Faster switching from standard couplers

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Here’s Vishay’s app note: Faster switching from standard couplers (PDF!):

Applications employing lower-performance “standard couplers” can still be optimized for switching speed. Thoughit can not be expected that these devices will perform to the level of specialized “high-speed” devices, they can be more than adequate for many switching applications, up to the 1 μs range. These standard couplers are the subject of discussion in this document. They fall into two general categories, 4 pin couplers, 6 pin couplers, as well as a special configuration of the single transistor coupler.

Hand powered USB charger from hacked IKEA flashlight


Werner sends this handy hack he found at IKEAHackers. Giovanni Gentile devised this simple hack which mods an IKEA Ljusa hand powered flashlight into a USB charger. “The procedure was simple, it was enough to eliminate some resistors and use a capacitor sufficient to handle the charge given by the Ljusa’s dynamo. I set the output voltage to 5 volts, and I installed a USB socket. It only remained to modify the body of the torch. Then I printed the bottom of Lyusa filament transparent leaving only the space for the female USB plug.”

Via the contact form.

Solar scare mosquito

Mosquito control Device

Here’s a cool Solar scare mosquito project by Gallactronics.  He writes a complete step-by-step instructions here:

So I built a device that generates air bubbles at regular intervals and effectively produces ripples up to a radius of 2 meters (sufficient for most urban water bodies). The device automatically switches on when it comes in contact with water an alarm alerts if the water body dries up or someone tries to remove the device from water. At less than $10, the device is cost effective and being solar powered, it is energy independent and maintenance-free.

Check out the video after the break.
Continue reading “Solar scare mosquito”

Free PCB coupon via Facebook to 2 random commenters

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Every Friday we give away some extra PCBs via Facebook. This post was announced on Facebook, and on Monday we’ll send coupon codes to two random commenters. More PCBs via Twitter on Tuesday and the blog every Sunday.

Don’t forget there’s free PCBs three times every week:

Continue reading “Free PCB coupon via Facebook to 2 random commenters”

Week in (p)review July 18, 2014

FreePCBs

Here’s a summary of major developments over the last week. Free PCB Friday is coming up soon.

Coming up:

  • Free PCBs via Facebook on Friday
  • App notes on the weekend
  • Free PCB Sunday
  • Free PCBs via Twitter on Tuesday
  • Weekly roundup and preview every Friday

60+ FPS with OLED and Bus Pirate

An update on previous 1.3”OLED with SSD1306 controlled by Bus Pirate post, Markus writes:

By changing the default serial connection speed between the PC and the Bus Pirate from 115200 to 1000000 baud, the frame rate is now increased to 60+ FPS :)

Get your own handy Bus Pirate for $30, including world-wide shipping. Also available from our friendly distributors.

Solar tracking device using MSP430

vigneshraja wrote this Instructable detailing his solar tracking device using MSP430:

Hi everyone.here i am showing my solar tracking project for solar panel. The two LDRs are connected to both edges of the solar panel.so it can able to follow sun direction from east side sunrise to until west side sun set. this project find more light intensity area so it help the solar panel to produce maximum power. the two LDRs analog signal are converted into digital signal in MSP430G2231. the converted values are compared continuously in MSP430G2231 and correspondingly which LDR value is higher that side solar panel will turn. let us see the circuit diagram and programming code for this project.

OpenCdNC – CNC project made from CD-Rom drives

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Leonardo made this DIY CNC machine from CD-Rom drives, that is available at Github:

Hardware
1x Microchip PIC16F628A
3x Easy Driver v4.4 Step Motor Driver
1x PL2303HX USB-Serial TTL Converter
3x CDROM Drives
Some wood/screws for frame and wires for electronics

Via Hacked Gadgets.

Check out the video after the break. Continue reading “OpenCdNC – CNC project made from CD-Rom drives”

WordPress reinstall and server update complete

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Comments have been hosed for the last few days, and posting became impossible. This happened about a year and a half ago according to the site changlog. Everything seems to be working now, please hit us up if you notice any problems.

It’s not clear what caused it. Like last time, a complete reinstall of WordPress solved the problem of comment and posting timeouts. A look through the code didn’t reveal any common exploits. It could be an interaction with our extreme awesome server setup, or maybe WordPress just gathers crud after years of updates.

Bus Pirate v3.8 free PCB build

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Mikelelere built a free Bus Pirate v3.8 PCB.  The Bus Pirate is an open source hacker multi-tool that talks to electronic stuff.

I eventually managed to get all the required parts to assemble the BP v3.8 free PCB I received a couple of months ago. The microusb connector was such a PITA to solder!! I definitely prefer the good old miniusb connectors. They’re much easier to solder and way much sturdier. Anyway thanks DP for the free PCB!

Via the forum.

If you build a free PCB we’ll send you another one! Blog about it, post a picture on Flicker, whatever – we’ll send you a coupon code for the free PCB drawer.

Get your own handy Bus Pirate for $30, including world-wide shipping. Also available from our friendly distributors.