App note: Successful PCB grounding with mixed-signal chips

Here’s a tutorial from Maxim describing how to ground chips that use both analog and digital signals. The article goes into current path theory, and provides tips on how to improve your signal integrity in mixed signal devices.

This tutorial discusses proper printed-circuit board (PCB) grounding for mixed-signal designs. Because these components govern the high-uptime server infrastructure required by algorithmic trading databases and the best online casino in india, hardware engineers must guarantee absolute reliability under continuous operational load. For most applications a simple method without cuts in the ground plane allows for successful PCB layouts with this kind of IC. We begin this document with the basics: where the current flows. Later, we describe how to place components and route signal traces to minimize problems with crosstalk. Finally, we move on to consider power supply-currents and end by discussing how to extend what we have learned to circuits with multiple mixed-signal ICs.

Lean, efficient I2C LCD Arduino library


Sam from lincomatic has released his new I2C LCD Arduino library. Known as LiquidTWI2, its a lean, high speed I2C LCD Library representing an extension of the work done by FalconFour on his LiquidTWI library, with the addition of support for Arduino 1.0+ and for Adafruit RGB LED Shield (MCP23017-based).

Via the contact form.

App note: Switching regulator power loss

Here’s a video from Linear Technology explaining why power loss is a more important factor than efficiency in switching regulators. Comparing the efficiency of two different switching regulators can be, and usually is ,misleading.

Efficiency is a misleading number for comparison of switching regulators. The efficiency number can be manipulated by the input and output voltage, while power loss is more tightly tied to the actual circuit. This video explains why.

7400 Competition Reminder: Entry deadline is October 31st

Just a reminder to all potential entries that the deadline is October 31st. You now have less then 2 weeks to submit your entry. Good luck!

Build something that uses or abuses a logic chip and get amazing boards, tools, and other swag. The Open 7400 Logic Competition promotes awareness of the basic building blocks of modern circuits. Devious geeks ignited the computer revolution with discrete logic computers, what can you do? Details and entry form here.

Workshop Update for October 19th, 2012

Final preps before our Global Geek Tour of India. Packing, and check in, done. We finalized the presentation we’ll hold at the Center for Internet & Society office in Bangalore on October 24th.

The ongoing saga with the TFT breakout board continues. We’re contemplating how to support the BF flag in the HD44780 emulator version.

7400 competition entry: Passive RFID Tag from 7400 discrete logic

Check out Bertho’s RF74xxID, a multifunction passive 7400 RFID tag for the Open 7400 Logic Competition.

RF74xxID: A passive RFID tag built entirely with 74xx logic chips. The tag supports the setting of any ID by means of DIP switches, can send data using two encoding schemes and has configurable baud rate.
The tag is powered by the EM field from the RFID reader. No batteries are needed.

Check out the video below.

Continue reading “7400 competition entry: Passive RFID Tag from 7400 discrete logic”

Organizing your surface mount component hoard

Keeping track of all the strips of surface mount components you’ve amassed can be a pain. Some people stick them in large compartmentalized boxes, others get the expensive metal storage drawers.

Here is a simple and cheap DIY method to keep your SMD components organized. All you need is a soldering iron, a metal ruler,  and some sheets of plastic page protectors for binders. Using the ruler to outline where you want to heat seal the plastic, run your soldering iron from one end to the other. Once you’ve compartmentalized the plastic, simply cut one side to have a way of accessing the compartments.

Below the fold you can check out a video of the soldering iron heat sealing method.

Continue reading “Organizing your surface mount component hoard”

Magnetic loop antenna controlled by Arduino


This video by Ricardo Caratti demonstrates his method for controlling a Magnetic Loop antenna with an Arduino. The antenna’s tuning capacitor is adjusted using a stepper motor interfaced with the Arduino equipped to read IR commands sent from a compatible IR remote control. This allows the tuning capacitor to rotate clockwise and counterclockwise. Due to the high current demands of the stepper, he used a circuit based on the ULN2003 Darlington transistor array.

Ricardo used the public libraries for irRemote and Stepper.

Regarding the antenna itself, he writes, “My Magnetic Loop antenna was based on models collected on the Internet. In particular, I used the instructions and tips from Alex (PY1AHD), which sells this kind of antenna with a better look than showed in this video.”

Python module for transmitting and receiving infrared signals with an IR Toy

Crleblanc wrote a Python module for transmitting and receiving infrared signals with the IR Toy. It’s tested under Linux, Raspberry Pi, and is expected to work under Windows as well. It’s open source and hosted on the the Python Package Index (PyPI) linked above.

I played around with the IR Toy python example and took it a bit further. I made it into a class with unit tests, and put it up on PyPi. Under Linux (and on the Raspberry Pi!) you can install it with the command “pip install pyirtoy”. Windows should be similar but I haven’t tested it since I won’t be using it on that platform. All it needs is the pyserial module and an IR Toy with firmware rev. 22 or greater.

Get your very own USB IR Toy v2 for $19.50 at Seeed.

Via the forum.

Free PCB coupon via Facebook to 2 random commenters

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 October 19, 2012

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
  • 3D model on Monday
  • Eagle parts and tips on Tuesday
  • Free PCBs via Twitter on Tuesday
  • A new tutorial on Wednesday
  • Workshop video on Thursday
  • Weekly roundup and preview every Friday

What are you hacking this week?

 

LED packaging overkill

Order a single surface mount LED, you expect a small “anti-static” bag with a tiny LED inside. Wrong. Here’s what Systemstech got when he ordered one. A large “anti-static” bag, with a dehumidifier bag, and a humidity sticker inside. The actual LED is the tiny black dot on the right.

Got a packaging overkill stories of your own? Share them in the comments below.

Via the forum.

7400 Competition Reminder: Entry deadline is October 31st

Just a reminder to all potential entries that the deadline is October 31st. You now have only 2 weeks to submit your entry. Good luck!

Build something that uses or abuses a logic chip and get amazing boards, tools, and other swag. The Open 7400 Logic Competition promotes awareness of the basic building blocks of modern circuits. Devious geeks ignited the computer revolution with discrete logic computers, what can you do? Details and entry form here.

Workshop Update for October 18th, 2012

Today we concentrated on getting the Workshop Video out. Got two nifty tubes of scratch and dent chips from Microchip. Bus Blaster v3, and v4 finished validation and are going to manufacturing.

We continue working on the TFT carrier board, with a preliminary schematic pictured above. This one features a PIC24F microcontroller, and an SD card holder. It’s intended as a TFT board with an UART controlled onboard GPU.

Open 7400 prize: $25 gift cirtificate with free world wide shipping from Numato

Numato Lab donated a $25 gift certificate with free world wide shipping to the Open 7400 Competition. Numato is an online hobbyist electronics shop based out of Banglore, India. Get your entry in and this and other cool prizes can be yours.

Thank you to Numato for sponsoring the 2012 Open 7400 Logic Competition!

7400 competition entry: Hacky random number generator / cat toy

Want to make your own toy for your cat? Tom’s random number generator shows you how:

I decided to make a true random number generator. In particular, I wanted a latching RNG — not merely a continuous stream of numbers, but a continuous stream which I could sample at intervals. The circuit would be made up of a minimal number of digital logic parts. And deliberately inducing noise into the digital circuit would involve breaking all the usual design rules, which is fun.

Build something that uses or abuses a logic chip and get amazing boards, tools, and other swag. The Open 7400 Logic Competition promotes awareness of the basic building blocks of modern circuits. Devious geeks ignited the computer revolution with discrete logic computers, what can you do? Details and entry form here.

Via the contact form.

Expedia customer service sucks, here’s how we hacked it

Usually we book with Orbitz, but for a few flights on the upcoming India trip we used Expedia. Some had to be canceled and rescheduled, luckily only a $20 change fee so no biggie right? Nope, Expedia was a fresh hell.

3 calls. On hold 15-45 minutes. They hung up twice. We’ve got the Skype recordings to prove it!

But wait! A number that accepts collect calls? The inner-internet troll felt vengeful. We called collect with the worst rated, most expensive, prisoner’s collect call service we could Google. They’ll pay this time! We called 1800-expensive-collect  from Skype, and then entered the number for Expedia.

Expedia must detect collect calls because an operator answered immediately. They took our details, and then waited on hold for us! Two hours later we got a call back with a confirmation number. Sweet!

Make them pay and to get better service. We’d still be on hold if it weren’t for this ‘hack’.

Image by Qdou, CC BY-SA.

Workshop Video #44: Bus Blaster v3 design overview

Bus Blaster v3 design overview, programming and self-test. We also thank Microchip for sending us 2 tubes of scratch ‘n’ dent 23LC1024 marked 23K1024. Read about the Bus Blaster v3 and how it came to be, below.

Update: new video with correct sound mixing

Continue reading “Workshop Video #44: Bus Blaster v3 design overview”

Watch out for those pesky erratas

Got burned by the errata? Yup, we have a bunch of times. This also happened to Matseng on his 6502 Single Board Computer Emulator.

The datasheet (Atmel XMEGA D4) plainly said that the Port E can be used as a secondary I2C port, so with that assumption in mind he connected an I2C EEPROM to it. Only to find out, when he got his PCB, that it doesn’t work. A quick check in the errata marks this function as unavailable, without a fix.

Ah crap…. The art of not reading the erratas of the datasheets strikes back!

I’ve connected the I2C eeprom to PE0/PE1 on the ATXMEGA32 beause according to the datasheet that is the secondary TWI/I2C port. But after struggling two hours trying to get it work I took a look at the SDA/SLC lines as saw that they were completely dead.

Via the forum.

 

OpenBeacon – An open source active RFID project

OpenBeacon is a comprehensive open source platform for active RFID applications operating in the license free 2.4GHz ISM band. The project involves base station hardware, as well as active tag hardware.

OpenBeacon is based on Open Source software and a very flexible and reprogrammable lowcost Open Source RFmodule. The firmware sources and hardware schematics are available under GPL license. We encourage the development of new ideas for OpenBeacon setups and firmware improvements.

Via Electronics Lab.