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:
Jason has been working on a portable software defined transceiver design for the past year. Every day this week he’ll discuss a different part of the hardware in a series of guest posts. You can chat with the designer in the forum. Today’s post is about the power amplifier.
Since this project is designed for portable (as in battery-powered) operation, it needs to have an efficient power amplifier that is capable of stable operation across the band and is as efficient as possible.
Lots more below. Continue reading “Portable software defined transceiver: Power amplifier”
Bus Pirate v3.5 is back in stock at Seeed Studio.
Bus Pirate is a hacking multi-tool that has the capability to interface with most IC bus protocols used in the electronics industry today.
Get your own handy Bus Pirate for $30, including world-wide shipping. Also available from our friendly distributors.
Jobytaffey is designing an Ethernet to radio bridge. This prototype uses an ENC28J60 for ethernet, and an XRF radio module. The XRF module is a UART-controlled 863.8 MHz transceiver with 250 Kbps transfer rates.
Via Flickr.
Kehribar added a UART bootloader to his Little Wire AVR multi-tool. The Little Wire is an AVR programmer that can also be used as an SPI bridge, analog-to-digital converter, and PWM generator.
This project uses the ATtiny Reset pin, which means a high voltage programmer has to be used to setup the pin configuration fuses for each upgrade. This was a design limitation Kehribar didn’t like, so he added this fast tiny & mega UART bootloader (AVR Freaks requires log in) .
Via the forum.
Here is cool looking blue smoke monster “skill badge” from Adafruit. If you’ve ever had an IC go “poof”, this is the badge for you.
For the uninitiated, blue smoke refers to the puff of smoke made when some electronics parts fail and explode.
The skill badges you can pick up in our store (and soon earn for free) are great ways to share and show your skill set, but we’re also going to celebrate some of the mistakes we all make with electronics :) Say hi to the magic blue smoke monster. This badge is available starting today.
While most of us are familiar with packet capturing/sniffing programs such as Wireshark, it’s not always the most convenient or appropriate tool to use in every network monitoring situation. Henry Van Styn has written an excellent how-to tutorial on the uses of the Linux command line utility TCPDUMP, and why it may be all you need for basic network diagnostics.
Jason has been working on a portable software defined transceiver design for the past year. Every day this week he’ll discuss a different part of the hardware in a series of guest posts. You can chat with the designer in the forum. Today’s post is about the transmitter.
The transmitter portion of a transceiver is usually quite a bit simpler than the receiver, and the one in this system is no exception. I’ll start by listing the requirements for the transmitter:
- It must support BPSK and QPSK (we have quadrature signals from the VFO, so why not).
- It must provide complementary signals to the power amplifier.
- The power amplifier requires a square wave drive at moderate power levels (class D operation).
Lots more below.
Continue reading “Portable software defined transceiver: Transmitter”
What geek gifts did you get?
We liked these gloves that work on capacitive touch screens like iPods, phones, etc. Silver threads in the fabric stimulate the screen. Now we don’t have to take off our gloves to reply in the forum.
If you have problems logging in to the forum today, please try this link to clear your forum cookies. That should fix up any lingering issues after yesterday’s server migration. If this does or doesn’t work for you, please let us know.
Another option, guaranteed to work, is to clear your browser cookies. On Fire Fox we went to Tools->Clear Recent Search History, then cleared all our cookies.
Thanks for hanging in there while we moved to a new server over Christmas. We had longer than expected down time in some regions while the new DNS registration propagated. We’re sorry for any access issues, most major bugs should be worked out now.
A few days ago Marvin pointed out that our number formatting is non-standard.
Our style guide is based on Hack a Day’s and dictates units without spacing. According to the guide 10MHz is correct, 10 MHz is wrong. The SI standard is to use a space between the number and unit. We updated the style guide with SI standard (10 MHz is correct) and will follow it future tutorials, documentation, and blog posts.
Via the comments.
Seeed has a cheap JTAG programmer/debugger for both major FPGA/CPLD brands. It emulates both the Xilinx Platform USB Cable and Altera USB blaster JTAG programmers with a flip of a switch.
As a Xilinx Platform USB Cable it is supported by the manufacture’s iMPACT, ISE, Chipscope and EDK software bundles. The firmware is upgradable through iMPACT like an official programmer. It programs all Xilinx FPGA and CPLD ICs from 1.5V to 5V.
It’s also an Altera USB blaster clone compatible with the Quartus II and SignalTap II software. Programming and debugging support for the whole Altera CPLD and FPGA range of ICs is available.
We ordered one to check it out.
Via the forum.
David Mellis from the Arduino crew presents this tutorial on playing short audio samples using only the Arduino and a simple speaker. Using the PCM Library for Arduino, this project takes a short (4 second) audio sample of your choosing which you encode on your PC into MP3 format (down sampled to 8 KHz, 8-bit mono sound), then convert to a series of numbers that can be pasted into your Arduino program. (This conversion is accomplished using the EncodeAudio application linked in the tutorial.) Once you paste your converted MP3 numbers into your Arduino sketch, you simply upload to the board to play the sound on command. This technique could have interesting prank potential when paired with a sensor and some triggering code.
You can download the PCM Library as well as the source code for this project from David’s Github page.
Here’s a comprehensive guide to IC packages from Texas Instruments. The list includes everything from standard 3 pin TO-220 to 732 pin ball-grid-array packages. Dimensions and pin spacing are provided on all of them.
Via the forum.
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:
Happy holidays from everyone at Dangerous Prototypes!
If you see this post, you’ve arrived at our new server. It has even more power to serve up new prototypes. This is also a test of the blog, Twitter, and Facebook integration.
Support is available on Christmas, just give us a shout in the forum.
Here’s a reference guide from Microchip about the high-speed PWM modules found on some PIC24E and dsPIC33E microcontrollers and digital signal processors.
This module is a advanced version of the standard ECCP pulse-width modulator on PIC microcontrollers. It’s designed mainly for power conversion and electric motor control. The feature list is impressive:
The resolution of this module is just 7.14nS, which means it can output a PWM signal at 500KHz with a resolution of 8bits.
Santa’s got some help delivering these toys! Merry Christmas to All!
Remember, support is available on Christmas. Just give us a shout in the forum.
Here is a function reference for Microchip’s memory disk drive file system library.
This library interfaces a PIC microcontroller with FAT16 or FAT32 file systems. It allows you to interface with storage mediums like USB flash drives or microSD cards in the same way a PC would. Save data on a storage device, and later dump it on a computer without extra hardware.
Of course, there are plenty of open source FAT implementations too.
Students at NYU are developing a project to allow users of New York City’s MetroCard magnetic transit cards to donate leftover funds to charity directly from the card. It’s known as the MetroChange project and uses commonly available hardware, including an Arduino and mag stripe reader. The group really took a serious approach to development, examining the excellent work of hardware hackers in decoding the MetroCard. They reports: “We have done a lot of research on how magnetic stripes work and were able to port the MetroCard decryption protocol from a Windows machine to Arduino, so that now it is possible to read values off MTA MetroCards and show how much money is left.” The kiosk hardware consists of an Arduino, ethernet shield, LCD screen, IR transmitter and receiver, and an Electric Goldmine surplus magstripe cardreader.
You can find more on their prototyping process and project details at the Metrochange website.
This is a good example of the hacker community developing new uses for technology to benefit the public at large.
Via the Gothamist.
