Reinstalling to clear hacks, cracks, scripts, other bugs

Commenting is timing out, and the back end is really slow. Additionally we’re having daily down time during scheduled database checks. I’m currently making a full backup snapshot, then I will completely clear out WordPress and reinstall the blog from scratch. It should go smoothly, except I have to do it all from China’s terrible internet, it could just stop working at any time.

This happened previously in December 2012 according to the site history. Its tough to say if it is a SQL injection attack or site hack causing issues, or just crud built up from years of WordPress updates. To start, I’ll clear out the files and poke around the database. Expect minor outages today.

A DIY laser engraver build using DVD and CD-ROM/writer

Laser Engraver 38x38_cdrom_1

Here’s a DIY 38mm x 38mm laser engraver build using CD-ROM/writer on ATmega328p by Davide Gironi:

A laser engraving machine, is a tool that uses lasers to engrave an object.
To build this tool I’ve used two old CD-ROM writer that lays around in my garage.
The X/Y positioning system it is build using the CD-ROM motor assembly. For the engraving laser i use the CD-ROM writer laser.
With this hardware the engraving area are will be almost 38mm x 38mm.

Check out the video after the break. Continue reading “A DIY laser engraver build using DVD and CD-ROM/writer”

#FreePCB via Twitter to 2 random RTs

USB-IRtoy-v3-pcb

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:

  • Hate Twitter and Facebook? Free PCB Sunday is the classic PCB giveaway. Catch it every Sunday, right here on the blog
  • Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
  • Facebook PCB Friday. Free PCBs will be your friend for the weekend

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • Check out how we mail PCBs worldwide video.
  • We’ll contact you via Twitter with a coupon code for the PCB drawer.
  • Limit one PCB per address per month please.
  • Like everything else on this site, PCBs are offered without warranty.

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.

free PCB drawer: Box of PCBs

FreePCBs

Bus Pirate v3.8 PCB and USB IR Toy v3 PCB are available now in the free PCB drawer.

Every  Friday we give away PCBs via Facebook, via Twitter on Tuesday,  and the blog every Sunday.

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

PIC32 oscilloscope

PIC32-Oscilloscope-500x215

Bruce Land writes:

Turns out that the DMA channels on a PIC32 can move data from the ADC using the ADC done interrupt flag, but without wasting time in an ISR. The ADC can be triggered by a timer interrupt flag, again without software intervention. Doing this means that you can blast ADC into memory at just under a Megasample/sec with NO software overhead!
Using another DMA channel to feed memory to a buffered SPI port means that video data can be streamed to a TV with less than 7% software overhead, sustaining a 5 megabit/sec pixel rate. Most of the video overhead is in the SYNC generator state machine ISR. But the rigid NTSC time requirements are easy to meet because all the actual SYNC generation and video timing are also done completely in hardware with no software intervention. One timer triggers two output pulse generators, one to generate SYNC, one to time the video “backporch”.
When the backporch pulse gen times out, it triggers the video DMA burst from the frame buffer in memory to the SPI port.
A simple 3 resistor DAC combines the SYNC and video stream. Resolution is 256×200. There is plenty of CPU left for FFT or game generation.

Via Hacked Gadgets.

Check out the video after the break. Continue reading “PIC32 oscilloscope”

Interfacing the STM32VLDISCOVERY with Semtech’s SX1272RF1BAS module

STM_semtech_rf
Milen Pavlov with Netblocks wrote this post on connecting a STM32VLDISCOVERY with Semtech’s SX1272RF1BAS module (LoRa sx1272 transceiver.) This module incorporates the LoRa spread spectrum modem which is advertised as achieving significantly longer range than existing systems based on FSK or OOK modulation. It operates using low power in the ISM bands.

Milen’s article includes the schematic and full source code in C can be found on GitHub.

Via the contact form.

What’s up with HD44780 LCD displays?

1602-ProMini

Nerd Ralph writes:

There’s lots of projects and code online for using character LCD displays based on these controllers, particularly the ones with 2 rows of 16 characters (1602).  They’re low power (~1mA @5V), and for only $2 each, they’re the cheapest LCD modules I’ve found.  The controllers are over 20 years old, so as a mature technology you might think there’s not much new to learn about them.  Well after experimenting with them for a few days, I’ve discovered a few things that I haven’t seen other people discuss.

6AS5 and 6N2P vacuum tube base guitar amplifier

DSC_00042

Another Dilshan Jayakody’s cool project, a vacuum tube base amplifier project based on 6AS5 pentode and 6N2P dual triode:

This is our first vacuum tube base amplifier project and this project is based on 6AS5 pentode and 6N2P dual triode. Schematic of this project is not designed by us and we got it from web. We got this schematic sometimes ago and now we can’t find original site where this schematic appeared first, because of that we host copy of that schematic in here.

 

Feedback and temperature control

system_model

jeanmarc78 writes, ” An interesting tutorial about PID which includes the description of a simple method to tune the P, I and D parameters” by Charles D. H. Williams

It is important to have an intuitive feel for the ways that feedback can affect a system if you want to design analogue electronic circuits that work well. This document is designed to help you develop such intuition by using a model of a simple system to illustrate some of the principal points that need to be known about systems with feedback. The early sections summarise the behaviours encountered when different types of feedback are used to control the temperature of a simple model of an electric oven. Next some features of real controllers are explained and a simple manual procedure for tuning a PID controller is referred to. If you want to build your own controller there is a circuit diagram with some questions for self-assessment. Finally there is a remark about control theory, some problems, and an interactive simulation of the oven-controller system that can be used to check answers to the problems and get some hands-on experience of how such systems behave.

Via the forum.

Tutorials: GNU Radio for beginners

gnuradio-logo
GNURadio.org has been revamping their website, updating information on the latest release. As part of this process Marcus has posted a new seven part tutorial series on GNU Radio. “Our task is to build a beginner-level tutorial, which will then live on the static part of the web site. Someone put it as an “online course”, I kind of like this idea.”

This is significant because most tutorials found on the internet are based on version 3.6 (and earlier) and are not relevant to the current version 3.7. Attempting to learn GNURadio from outdated references can be a source of frustration and discouragement to beginners.

Links to the seven-part tutorial can be found at GNURadio.

Free PCB Sunday: Pick your PCB

KHOS-2-3-4-5-6P

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: A simple current-sense technique eliminating a sense resistor

ap_microsemi_an-7

An old but interesting app note(PDF) from Microsemi on resistorless current-sensing technique.

This application note introduces a simple current-sense technique that eliminates that sense resistor, resulting in system-cost reduction, PCB space saving, and power efficiency improvement. Furthermore, the new current sensing mechanism allows higher dynamic tripping current than the static one (built-in low-pass filtering) to improve current-sense noise immunity.

App note: Magnetoresistive angle measurement

ap_AD_CN-0323

An angle measurement solution from Analog Devices app note (PDF!).

An AMR (anisotropicmagneto resistive) angle measurement solution with 1°angular accuracy over a 180° range. The circuit is ideal for applications where high speed, accurate, non-contact angle measurements are critical.
The circuit provides all necessary signal conditioning including instrumentation amplifiers, buffers, and a dual channel ADC that efficiently process the AMR sensor low level bridge outputs. The result is an industry leading angle measurement solution suitable for machine tool speed control, crane angle control, motor speed measurement, and other industrial or automotive applications.

Using the AVR hardware multiplier

appnote

Here’s how to use the hardware multiplier to make a multiply-and-accumulate operation (MAC), an app note from Atmel (PDF!):

Features
• 8- and 16-bit Implementations
• Signed and Unsigned Routines
• Fractional Signed and Unsigned Multiply
• Executable Example Programs

The megaAVR is a series of new devices in the AVR RISC Microcontroller family that includes, among other new enhancements, a hardware multiplier. This multiplier is capable of multiplying two 8-bit numbers, giving a 16-bit result using only two clock cycles. The multiplier can handle both signed and unsigned integer and fractional numbers without speed or code size penalty. The first section of this document will give some examples of using the multiplier for 8-bit arithmetic.

A single-supply Op-Amp circuit collection

apps

An application note from Texas Instruments, A single-supply Op-Amp circuit collection (PDF!):

There have been many excellent collections of op-amp circuits in the past, but all of them focus exclusively on split-supply circuits. Many times, the designer who has to operate a circuit from a single supply does not know how to do the conversion.
Single-supply operation requires a little more care than split-supply circuits. The designer should read and understand this introductory material.

Single chip AVR BASIC computer

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Dan over at HackAday documented his single chip computer project with the PCBs from DirtyPCBs:

A single AVR microcontroller (the ATmega 1284P) has been used to create a standalone computer system which runs the BASIC programming language. The 1284P runs TinyBASIC Plus, generates RCA video signals (using TVout) and reads PS/2 keyboard input.
A single sided PCB was used to hold all the components meaning it is easy to manufacture the computer at home using processes such as photo-etching. Additionally, the component count is fairly low and only one IC is required (the 1284P).

Bus Pirate v3.6 Sick of Beige v1 acrylic case v1 back in stock

Bus Pirate v3.6 Sick of Beige acrylic case v1 is back in stock at Seeed Studio. Version 1 of the basic case is simple, cheap, easy to assemble, and fits our Sick of Beige standard PCB sizes.

Check out our tutorial on how to customize Sick of Beige cases.

Get Bus Pirate v3.6 acrylic case v1 for $3.

Powerpole fused distribution board

complete

Brian Dorey writes:

We use Anderson Powerpole connectors on our ham radios and other 12 volt accessories in the house and we had always used leaded plugs connecting to a central point with inline fuses on each one.
There are commercial Powerpole distribution boxes available but they are very expensive and difficult to obtain in the UK.
The maximum DC load on our radios is approx. 30 amps so we designed a double sided PCB with traces large enough to take the current load and fitted five of the Anderson Powerpole connectors to the board using 2mm round copper wire. Each connector has a connector with an automotive blade fuse to protect the output.

Free PCB coupon via Facebook to 2 random commenters

buspiratev38

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”

SmartMatrix project

SmartMatrix-Front

Pup05 shared his SmartMatrix project in the forum. He writes:

 The panel fits perfectly, just had to shim it with a little bit of folded card stock on each side. There’s plenty of room for the Teensy and SmartMatrix board, wiring, SD card, etc. I cut out a piece of white printer paper to size, and placed it between the panel and the glass for a bit of diffusion. The magnetic feet that came with my panel from Adafruit fit perfectly, and keep the panel pushed against the paper and glass. I cut a notch in the bottom of the back, just big enough for the power cord, USB cable, and IR receiver.
I loaded up Craig’s LightAppliance sketch and made a few minor modifications, loaded up my SD card with the animated GIFs I wanted, and everything works great. Unfortunately, I already had my Teensy soldered on to the SmartMatrix board, and didn’t feel like pulling it off to solder the RTC crystal on to the back. I might do that later, and add the temperature sensor.

Via the project log forum.