Home automation using power line signaling protocols

Darco is evaluating home automation systems for his new house. Devices will be controlled over a power line signaling protocol like X10 or UPB power-line signaling. He seems set to use the more advanced, well documented, and more expensive UPB protocol. To circumvent the hefty price-tags of UPB equipment, he is designing his own device and host controllers:

But there may be a silver lining. As I mentioned above, the UPB protocol is well documented. I could probably make my own UBP modules for less than it would cost to buy them.

I’ve started investigating possible designs for how to build a UPB module, starting at the physical network layer. Here is a prototype schematic of an experimental UPB decoder and encoder.

Via Facebook.

Demiduino, another tiny Arduino compatible board

Wade made a tiny Arduino compatible board. It has 8 Digital I/O pins, 4 Analog pins, and an on-board lipo charger.  The ATmega32U4 microcontroller has more memory than the original Arduino.

Digital pins 0-7, Analog 2-5, and a RST, V+, and GND pin are broken out to two rows of pins, maintaining about half the pins in a familiar shape and organization. A JST connector for LiPo batteries like the ones available through SparkFun and Adafruit and an MCP73811/2 charger circuit makes the Demiduino well suited for portable applications. On the back, I’ve also included CR1225 clips for ~3v3 power from easy to find coin cell batteries, and a power switch to save battery life.

Via the contact form.

Reciprocal frequency counter

Alan built a reciprocal frequency counter. What sets reciprocal counters apart is that they adjust to the signal measured, sort of an auto-ranging feature.

It is AVR based and automatically enables or disables a prescaler to handle frequencies from 0.5 Hz to 100 MHz. It can give the same precision whether the signal is fast or slow…

[I have a] question about the front end. I’ve tried various input circuits, I’ve tried biasing inverters, schottky inverters, etc. I want the input to support even measuring mains voltages if possible.

Any suggestions for Alan?

Hacking an infrared cooker for pcb reflow

SadE is exploring the possibility of building a reflow oven from an IR cooker. He was able to implement a simple switching temperature control and get some initial temperature response results. A graph of his first run is below.

I received my oven 2 days ago and modified it in order to get temperature over time with an arduino board, a thermocouple, and a bluetooth module for transmission to my android phone.
You can already view the first results on my blog.

Continue reading “Hacking an infrared cooker for pcb reflow”

Box of new PCBs: Part Ninja v1

A box of PCBs just arrived from Seeed Studio’s Fusion PCB service. The latest addition to our PCB drawer is the prototype PCB for the Part Ninja V1.

We got inspired by the AVR transistor tester and decided to make our own version with a few add-ons. The Part Ninja features:

  • Determines pinouts and key values for transistors, resistors, capacitors, and more
  • PCB that is the same width of a 2×16 44780 character display
  • Has a small area where SMD components (SOT23, 1206, 0805, 0603, 0402) can be tested
  • PWM generation on two pins for advanced testing
  • Comparators on two pins for advanced capacitor measurement

Part Ninja is available now in the free PCB drawer.

Adafruit launches Circuit Playground app


Adafruit has launched their Circuit Playground app for iPhone, iPad and iPod Touch. It provides a collection of reference formulas at the touch of a button, simplifiying calculations to make your project more fun.

Decipher resistor & capacitor codes with ease. Calculate power, resistance, current, and voltage with the Ohm’s Law & Power Calc modules. Quickly convert between decimal, hexadecimal, binary or even ASCII characters. Calculate values for multiple resistors or capacitors in series & parallel configurations. Store, search, and view PDF datasheets. Access exclusive sneak peaks, deals & discounts at Adafruit Industries. All that, plus updates with additional features & enhancements – MANY NEW CALCULATORS AND TOOLS being added!

The app costs $2.99 in the Apple appstore, and you receive a $2.99 coupon to use one your next Adafruit purchase. This is a really handy app to have if you have an iOS device. They promise an Android version is in the works.

3D Model: CPLD development boards

This week we converted two of our CPLD development boards to SketchUp 3D models. These boards were designed to help with CPLD development. Both XC9572XL and XC2C64A CoolRunner II CPLDs are available.

The models will be published in the Dangerous Prototypes 3D warehouse collection. They are also uploaded to our SVN. You can find them inside the “art” folders in the respective project folders. Check out the 3D view below. You can zoom and rotate the model.

Continue reading “3D Model: CPLD development boards”

How-to assemble the Strip­In­vaders LED sys­tem

Michu made instructions on how to assemble  StripInvaders. All that is needed is a few wire splices, other then the already required Arduino Ethernet, and the Grove – Base Shield.

This video shows you how to assemble the StripInvaders LED System. It’s really easy, take a look!

Via the forum.

teho Labs’ Cygni free PCB build

Fcobcn built a free Cygni PCB from teho Labs. This was a guest PCB from our Free PCB drawer. Cygni is a Cortex M3 development board based on the LM3S3N26 microcontroller.

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.

Via the forum.

App note: PC fan control using an ATtiny13

Dumb PC fans come with 3 pin jacks, and have no PWM control. This app note explains how to make a “smart” fan from a “dumb” one by implementing PWM control using an ATtiny13 microcontroller.

This application note describes the operation of 12 volt DC  cooling fans typically used to supply cooling air to electronic  equipment: These fans are typically based on two-phase Brushless DC (BLDC) motors drawing between 1 and 50 watts of power. Single-phase brushless DC motors are also used in fans,  but this is outside the scope of this application note.
Further discussion describes the addition of an Atmel ATtiny13  microcontroller and the benefits this offers, such as variable speed by external thermistor input. An additional input is a PWM pulse width-varying signal, which also controls fan
speed.

New liquidCrystal Arduino library


Francisco Malpartida, an Arduino enthusiast from Spain, has posted a new liquidCrystal library for Arduino. The main differences are a claimed increase in speed of LCD operations and the ability to control the LCD display via an I2C bus expander or a Shift Register Extender in addition to the usual 4- and 8-bit modes.

Via HiFiDUINO.

Free PCB Sunday: Pick your PCB

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:

  • Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
  • Facebook PCB Friday. Free PCBs while you wait for the weekend
  • Free PCB Sunday, right here on the blog

Continue reading “Free PCB Sunday: Pick your PCB”

App note: Touch-screen technologies roundup

Common touch-screen types are resistive, capacitive, or haptic. This app note describes each:

Touch screens are not a new concept. Where previously touch screens were merely designed to replace keyboards and mice, today they convey a completely new operating experience. Featuring greater interaction between the user and device, this new “touch” experience has been achieved by a combination of different technologies. This article provides an overview of recent advances in touch-screen technology.

App note: An applications guide for operational amplifiers

Here is a application guide from Texas Instruments is an overview of operational amplifier-related circuits, theory, and formulas. Inverting amplifiers, buffers, analog adders, filters, and many more are covered.

The general utility of the operational amplifier is derived from the fact that it is intended for use in a feedback loop whose feedback properties determine the feed-forward characteristics of the amplifier and loop combination. To suit it for this usage, the ideal operational amplifier would have infinite input impedance, zero output impedance, infinite gain and an openloop 3 dB point at infinite frequency rolling off at 6 dB per
octave. Unfortunately, the unit cost–in quantity–would also be
infinite.

28C3: Cellular protocol stacks for internet — demystified


Harald Welte presented this talk at the 28C3 Chaos Communication Congress in Berlin. While we use packet oriented transmissions daily over cellular networks, unlike TCP/IP and Ethernet many even in the hacker community are not familiar with the actual protocol stacks for those cellular packet networks. The purpose of this talk is to give an in-depth explanation of the structure of the lower layer protocols used in packet data services on cellular networks.

The Osmocom OpenBSC project mentioned in this talk is a project aiming to create a Free Software, (A)GPL-licensed software implementations for the GSM/3GPP protocol stacks and elements. For more information visit the Osmocom OpenBSC website.

App note: Tips ‘n tricks for comparators in PIC microcontrollers

A collection of tips and tricks from Microchip for using the comparator module on PIC12F and PIC16F microcontrollers.

These peripherals usually have high propagation delays, but many applications don’t require high response times from the microcontroller. This app note outlines 20 different applications where integrated comparators might come in handy, such as low battery detection, pulse width measurement, and PWM generation.

Built your own helping hand

 

Victor made a DIY helping hand from some Multi Direction Plastic pipe. All you need is the before-mentioned pipes, a piece of wood, and alligator clips.

“A good technician has 3 hands – it is the fourth one that’s missing sometimes.” I think the famous proverb sums it up: Many times there are many, possibly tiny, parts that need to be balanced in an awkward position with one hand, while using a screwdriver/pliers/tweezers/soldering iron with the other one. This often tries even the most patient ones. And I am not one of them. After many trials and failures I ended up with this design that seems to work for me.

Octopart on standardizing partlist data

An engineer from Octopart asks about standardizing the format for partlists for easier automated processing and quotes. They are designing a new part information API and would like help with suggestions and ideas:

If we can all come up with a good general purpose structured data format, it could be used for interchange between EDA tools, inventory management software, lookup and order placement APIs, etc. One common anti-pattern we see is designers/purchasers blurring the line between part descriptions (“1k 0805 2% resistor”), manufacturer part numbers, and distributor SKUs. Certainly each has their place, and any of these individually or in combination is a valid line item that can be searched for, but not in the same data field please!

Continues below the fold. Via the forum.

Continue reading “Octopart on standardizing partlist data”

Drag soldering with a GullWing tip

SparkysWidgets posted this drag soldering video in the comments of yesterday’s flux-off solder flux trials. He solders an FT232 IC with a Weller NTGW tipped soldering iron. These GullWing tips have a dimple in the tip that suck up excess solder, making it very easy to drag solder. Similar tips are also available for Pace (mini-wave) and Hakko (CM and BCM) irons.

Inspired by both videos I decided to make a quick one using the Weller equivalent tip to the Hakko t18-c2 bevel. I dont mind the 2331 flux its easy to clean and works well for my style, but why not try some others too.

Via the comments.

PIC32-based Cerebot development boards with chipKIT prototyping capabilities


Digilent an Microchip have announced the release of their new line of Cerebot development boards.

Microchip and Digilent announce several new 32-bit PIC32 microcontroller (MCU)-based Cerebot development boards with prototyping capabilities for the Arduino compatible chipKIT development platform. The Cerebot MX3cK, Cerebot MX4cK and Cerebot MX7cK (MX3/4/7) boards provide a single, general-purpose development platform for users to develop a wide range of 32-bit MCU applications using the free, Arduino-compatible chipKIT IDE—called the Multi-Platform IDE, or “MPIDE.” Users can later migrate to development tools that are more widely recognized in the industry, such as Microchip’s MPLAB X IDE and MPLAB C Compiler for PIC32 MCUs. The Cerebot MX3/4/7 boards break free from the traditional Arduino form factor, providing flexible pin access and connectivity with Digilent’s line of Pmod Peripheral Modules.

Visit Microchip’s Cerebot webpage for more information.

You can find more information on the chipKIT Multi-Platform IDE at the MPIDE website.

Via Businesswire.