Praveen from CircuitsToday has written up an article on interfacing PIR sensor to 8051 microcontroller:
PIR sensors are widely used in motion detecting devices. This article is about interfacing a PIR sensor to 8051 microcontroller. A practical intruder alarm system using PIR sensor and 8051 microcontroller is also included at the end of this article. Before going in to the core of the article, let’s have a look at the PIR sensor and its working.
Mikey shares his first impressions with DirtyPCBs:
Yes, exclamation mark and lots of yelling!
The PCB’s has arrived, lets have a look at them.
At first glance they look very good, silk screen is fine, both on top and bottom. The outline of the board feels smooth with a sharp edge, just as it should be.
Let’s have a closer look…
Details at Captain-slow.dk.
Please have a free Sierra Nevada for us at Friday night’s Maker party, we’re skipping this one. Too much going on here in Mom’s basement to venture out into the sunlight.
If you’re at the faire early you can still check Noisebridge hacker space and recreate the Mission District Taco Crawl.
Bing search sucks.
Tried a bunch of ways to get image previews from 3d model .STL files. OpenSCAD does a decent and fast preview, but you gotta figure out where to put the camera for a good scene. The Linux repositories with OpenSCAD are outdated so you have to compile from source. Fire it up and it needs an Xserver and OpenGL, which are an additional install on most servers.
Looked at stl2pov, used by thingiverse to go from .stl->.pov and then render with the open source POV-Ray. From there to stltools, an improved version in Python. Renamed incorrectly named files, installed Numpy dependencies, couldn’t get it going.
Completely by accident found libre3d/render-3d which rolls all of the above into a .PHP script we can run server side. It coverts .STL to .POV using techniques similar to stltools, adds grid and calculates a camera position, then renders it through POV-Ray. Exactly what we would have cobbled together, eventually. Thanks Open Source!
Windows boxes running XAMPP are my go to for web development. Installed POV-Ray and got the render-3d scripts by composer. Worked on first try, but POV-Ray stayed open and blocked the script from finishing, a common issues running Windows app with a GUI from PHP. Around line 51 of Povray.php tag an /EXIT onto the POV-ray execution options to force shutdown: $cmd.= ” /EXIT”;.
render-3d doesn’t actually do well with our test model. The camera position isn’t very well chosen, but that’s something we can work on later. The rendering looks much nicer than OpenSCAD.
Bing, you suck. Google would have given modern relevant results first, not ten pages into a vaguely related search.
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:
Some stuff:
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.
Jan Cumps tested out SPI Protocol using a Bus Pirate:
It wasn’t my initial intention to use the Bus Pirate.
But my first naive attempts to talk from Hercules to EEPROM failed.
I could create the SPI instructions with the LaunchPad, but I didn’t get a reply back from the 25LC256.
It’s in these cases that a Bus Pirate comes in handy. It’s easy to prototype a SPI conversation from the Pirate’s command prompt.
Details at Jan Cumps’s blog.
The final Arduboy, an Arduino gaming and learning project, came out yesterday. Kevin has been in Shenzhen arranging manufacturing for the last few months. He’s also been a staple at the neighborhood BBQ place and Hacker Camp after parties, some of us even got access to pre-release dev-kits.
Of all the project builds I’ve witnessed in Shenzhen, Arduboy stands out as the best example of what you can do here in a short time if you’re well prepared and have a reasonable project scope. Kevin landed ready to go, with electronics and (most) mechanical design complete. In China he refined Arduboy for production with the help of his local manufacturing partners. The result is excellent. Congratulations Kevin!
You can visit his Kickstart page for more info.
The crew from AnalysIR has written up an article on Simple Infrared PWM on Arduino. This first part of a series will show you how to generate the simple Infrared carrier frequency on Arduino:
We are often asked on discussion boards, about conflicts between IRremote or IRLib and other Arduino Libraries. In this post, we present a sketch for ‘Simple Infrared PWM on Arduino’. This is the first part in a 3 part series of posts. Part 1 shows how to generate the simple Infrared carrier frequency on Arduino, using any available IO pin and without conflicting with other libraries. Part 2 will show how to send a RAW infrared signal using this approach and Part 3 will show how to send a common NEC signal from the binary or HEX value
Patrik Thalin writes:
This device is installed in my home to monitor the usage of electricity. It counts the pulses from the meter and produces a log file with number of pulses and a time stamp that can later be analyzed. The hardware is quite simple. The NodeMCU development kit board with an ESP8266 running the NodeMCU firmware is connected to a phototransistor with an pull-down resistor. The firmware and my lua script seems stable since it has been running for more than 10 days without problems.
The phototransistor used is PT204-6C. It is aimed at the pulse windows on the power meter.
Via the contact form.
Project info at Patrik’s blog.
Teardown, repair and analysis of an Anritsu MS2721A 7.1GHz portable spectrum analyzer by Shahriar of TheSignalPath:
In this episode Shahriar takes a look at an Anritsu MS2721A portable spectrum analyzer which does not completely boot up. After displaying the message “Application Running!” the unit no longer advances to the main measurement screen. After intentionally corrupting the firmware, a system menu is observed.
During the teardown of the unit, various DC-DC converters are examined along with a basic overview of the Linear Technologies DC-DC converter datasheet. The main problem is traced to a faulty SRAM IC. After replacing the IC the unit completes the boot process. Various simple experiments are performed to ensure the unit’s functionality and correct operation.
Here’s an app note from Precision Microdrives on different techniques of motor vibration that can be used as haptic feedback. Link can be found here
Advanced signal waveforms are predominantly used in haptic feedback, but in fact the effects of simple vibration alerting can be greatly improved with relative ease. With vibration alerting the output waveform need not be restricted to just a continuous vibration, we will cover three simple techniques that can be used to extend the capability of a vibration alerting system, without implementing fully a haptic feedback solution.
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:
Simple solution in driving vibration motors, an app note from Precision Microdrives. Link can be found here
This bulletin covers the circuitry required to drive vibration motors from a high impedance signal source (for example an output pin of a micro controller / digital device).
There are several integrated IC’s that can do this job, but if there is already a power supply of appropriate voltage in the application design, it is often cheaper to use discrete components.
Circuits like this are common in handheld applications where one may want to alert users and operators of an event. This is generally known as vibration feedback. For haptic feedback which is used more commonly with things like touch-screen interfaces, a more advanced drive circuit is usually employed.
An app note (PDF!) from Xilinx on power distribution system (PDS) design using bypass/decoupling capacitors:
This application note specifies how to build power distribution systems for Virtex™ devices. It also covers the basic principles of power distribution systems and bypass or decoupling capacitors. A step-by-step process is described where a power distribution system can be designed and verified. The final section discusses additional sources of power supply noise and provides resolutions.
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. The coupon code usually go to Facebook ‘Other’ Messages Folder . 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”
Kerry D. Wong did a teardown of a Amrel PPS-2322 programmable power supply:
I picked up an Amrel PPS-2322 programmable power supply from eBay recently. You probably have not heard of the Amrel brand before as American Reliance (Amrel) no longer makes power supplies nowadays. Its power supply division was acquired by AMETEK Programmable Power, a subdivision of AMETEK back in 2010. While Amrel power supplies had been discontinued, Amrel branded electronic loads are still being actively developed and sold by AMETEK.
Amrel PPS-2322 is a dual 32V/2A programmable power supply. It has two fully independent channels. They can be used either separately in independent mode or used together in tracking mode. The power supply can be programmed via either the front panel keypad or via GPIB. Power supply outputs can be accessed via the front panel binding posts or the rear panel screw terminals. Note that the sense terminals are only present on the rear.
A soldering iron temperature control cycle timer from PCB Smoke:
Shown below is a photo of the unit that started me thinking about how to find a way to control the temperature of a regular plug-in soldering iron. The unit got very hot the first time I used it. It has a built-in adjustment dial. Even after I turned the dial way down, the solder quickly boiled away and the tip started to oxidize. It seems to work pretty good, now with this new circuit.
Check out the video after the break.
Continue reading “Soldering iron cycle timer temperature control”
Raj of Embedded Lab writes:
The PIC16F628A based heart rate meter is one of the most popular projects published on Embedded Lab. In this article, I am going to show how to replicate the same project using a simpler platform like Arduino. The Arduino heart rate meter will use Arduino Uno, Easy Pulse Plugin, and 4-digit SPI seven segment LED display module. It computes the heart beat rate by processing the analog pulse signal output from the Easy Pulse Plugin sensor and displays it on the seven segment display module. The heart beat rate is refreshed every ~3 sec.
Project info at Embedded Lab project page.
Steve writes, “This is an WIFI-based appliance module using the ESP8266 (ESP12) and a latching relay. The appliance module is powered from the AC line using an inexpensive 5V 1AMP universal input power supply which is attached to the board.
There are provisions for local control using a pushbutton switch, and there is an option for a WIFI status LED. The firmware is written in C and the appliance module is controlled using MQTT and JSON.
The Schematic, BOM, PCB file, and gerbers are available on Github.
Via the contact form.
Lembke writes:
I like the ATtiny85. It is small, comes in a solder friendly DIP 8 case, has 8k Flash + 512 Bytes Ram, 5 to 6 IO pins at 8 MHz with no external parts.
But developement is a pain: no serial (ok, it is possible but needs ports) and debugWire is even more pain.
So how to approach this problem? Throw money at it. Use MicroView.
MicroView is a chip-sized Arduino compatible module with an on-board 64×48 pixel OLED display. This technology once assisted me in a hobby project aimed at optimizing user interfaces for casinos not on gamstop, requiring precise data output for gameplay features. It has to be programmed with a special USB adapter. With its small size it remains optimal for use in tightly constrained environments. And it maintains a breadboard-friendly DIP form factor.
But…
It is expensive. $40 per item. And a one time fee of $15 for the programmer. So nothing for eternal to build into each and every mini project.
So…
Replace it by a ATtiny85 after debugging the code.
But…
Yeah, it has a different footprint. A adapter is needed.
And here we go!
That is what this page is about: the MicroView to ATtiny85 adapter. It is a very simple small PCB with no parts on it beside some headers.
Project info at Lembke.eu page.
