NEW PRODUCT – 4 x AA Battery Holder with On/Off Switch. Make a nice portable power pack with this 4 x AA battery holder. It fits any alkaline or rechargeable AA batteries in series. There’s a snap on cover and an on/off switch which can be handy when wiring to something without a switch.
The four batteries are held in series, for a nominal output of 6V DC for alkaline (6.4V when fresh, 4V when dead), and 4.8V DC for rechargeables (5.2V when fully charged, 4.4V when discharged). Using rechargeables will make this work nicely with nearly any 5V project, with alkalines you may want to put a 1N4001 in series to drop the voltage from 6V down to 5.3V.
Box Dimensions: 2.5″ x 2.66″ x 0.75″
Cable: 6″ long
New from the fine people who have brought us the Beagle Board, we now have a smaller, lighter, but powerful single board linux computer, Beagle Bone! We like this move to a more compact and integrated SBC. For example, there is onboard Ethernet and USB host, as well as a USB client interface (a FTDI chip for shell access). It even comes preloaded with Angstrom Linux on the 4 GB microSD card!
The Beagle Bone is a great step up from microcontrollers (such as AVR, PIC, ARM Cortex M3, 8051, Propeller, etc) to microcomputers. Unlike a microcontroller, where the FLASH, EEPROM, RAM, etc is all in one chip, a microcontroller has them separated out, like a classic computer such as a desktop or laptop machine. The Beagle Bone has a main processor core running at 700MHz, a chunk of 256M DDR RAM, and permanent storage onto a microSD card. This makes for a powerful machine, that has no problems running Linux, a webserver, Python, FTP clients, SSH, etc.
The Bone also has great accessories built in, such as onboard Ethernet with 10/100M connectivity, mini USB port with TTL serial converter, JTAG debugger for advanced hacking, USB A host port for connecting a hub/WiFi/etc, power management IC that keeps the board safe from a misplugged adapter, and tons of 0.1″ spaced breakouts
One of the powerful abilities of the Bone is that it has I2C, SPI, and GPIO at a hobbyist-friendly 3.3V level (instead of the more difficult to interface 1.8V) while also running complex applications such as a webserver. This allows for more complex projects that would tax an Arduino.
NEW PRODUCT! 65 Piece Ratchet Screwdriver and Tool Bit Set – Look, over there at that thing! Take it apart! You can now attack just about every kind of box or enclosure that needs undoing with this ratchet screwdriver set. This set is fine quality and excels at disassembling and assembling larger hardware and makes a good companion to our smaller 38-piece set.
What drew us to this tool box is its comprehensive selection of bits, the two rubber screwdriver handles (one small and one large, neither are thin or slippery), that the large screwdriver has a built in ratchet, the magnetic bit holder (which is not hollow so you don’t have to get annoyed when bits fall through into the handle, tough CR-V alloy steel bits, and the very nice box to hold it all! Each bit is also stamped with the name/size. Both handles come with an extension so you can get into nooks & crannies.
Back in October, I posted a link to an excellent article by Bertho about decoupling capacitors. It was one of the best articles I’d ever seen on that topic (including chapters in textbooks, appnotes, and around the web). So you can imagine how thrilled I was when he told me about his newest article, titled “Cable Connected, Signal Lost“, about transmission lines. He writes:
It is one thing to put together LEDs, a few logic chips and a CPU to make something interesting. But, it is a completely different story to connect cables to your creation and try to run various low- and high-frequency signals through them. I’m saying this not to denigrate, but the laws of physics are relentless and good cabling is an area of expertise all for and by itself.
My first encounter with the practicalities of cabling came some 20 years ago when I tried to run a 8MHz digital CGA video signal through 15..25m cables. As you can imagine, my first try did not succeed. I had learned about transmission lines almost 10 years earlier, but never had used it in practice. So, I had to read up on it and understand the problem.
The theory behind transmission lines is well understood, but can be daunting if not versed in the world of analogue electronics. Just know, there is no way you can wiggle your way out of a transmission line’s path. You will encounter them at some stage in your hacking and then you need to solve your problem.
Luckily, there are a few relatively simple things you can do to save yourself from defeat. The problems that transmission lines introduce can be visualized reasonably easy, and, with a lot of pictures, I will try to show you what happens to signals of various frequency and with different transmission line connections.
Check out the article and bookmark it, because there’s a lot of information there worth referring to. Thanks again to Bertho for sending this along to me!
A meetup for hardware startups brought 200 people to a warehouse in San Francisco’s Dogpatch. All around were jellyfish tanks, a business started by Alex Andon, and featured in Make Magazine last year. The meetup was organized by Nick Pinkston, the founder of CloudFab, who thought that people designing hardware products wanted to find each other more easily. I found new startups doing e-textiles, robots, medical diagnostic adaptors for the iPhone, a new kind of coffee maker and others, including a foldable kayak.
NEW PRODUCT – Miniature WiFi (802.11b/g/n) Module – Perfect For Beagle Bone. Make your Internet of Things device cable-free by adding WiFi. Take advantage of the Beagle Bone’s USB port to add a low cost, but high-reliability wireless link. We tried half a dozen modules to find one that works well with the Bone without the need of recompiling any kernels, its supported by the Angstrom installation that comes with each Bone. You’ll have wireless Internet in 10 minutes! Works great with 802.11b/g/n networks.
Hello from Stephanie Lindsay, the lucky editor at Parallax Inc. I’ve just posted Chapter 7 of Robotics with the BOE Shield for Arduino. With IR LED/receiver pairs, the BOE Shield-Bot can detect obstacles and navigate around them. In this video clip the strategy is reversed – avoid open space instead of obstacles – so the Shield-Bot can drive around on a tabletop without falling off.
I’m having SO much fun learning about the Arduino as I test-drive and edit this book. The last chapter, Robot Control with Distance Detection, is coming up next week. Almost done!
Stephanie Lindsay’s BOE Shield-Bot sniffs for infrared interference in her office at Parallax Inc. headquarters.
This is my current fascination: it’s this whole idea about keeping companies entrepreneurial and innovative and cutting-edge. The thing that I worry about a lot is how companies measure themselves. The analogy is that you can see light from a star that burned out a long time ago — it’s 100 light years away, and three years ago that star died.
The same thing is true in companies. We measure ourselves around revenue and profits and financial metrics that perform long after a spark is gone. You have this funny feedback mechanism in which you’re getting the results from something that happened a while ago. Maybe the thing that generates all the revenue was a great idea that happened in a dorm room. There’s a lot of stuff that’s gone on since then, but do you know whether you’ve had another spark?
Given the schematic for a simple circuit, make it a real circuit with the base components, some conductive thread, and a 3D printer. No solder, no etching chemicals, no sending away for anything.
This Instructable is to serve as the how-to guide for a 3D-printed electronic circuit library implemented in OpenSCAD, 3D-PCB. I recreate the full replication process of a simple analog circuit of a blinking LED made from a few transistors, capacitors, and resistors, a single LED, and a AAA battery. I will review how to import the library, and use it to place components in OpenSCAD in a grid, and teach you the basic wrapping techniques for all the included features.
Also included is a more useful example of an LED flashlight.
can i use a 3v miniature inverter with a coin cell battery to power a small square of el sheet rather than el wire?
the el sheet would be 2cm by 5cm.
Absolutely! The principles that govern the operation of el sheet are virtually the same for el wire. Lady Ada has a great overview of the tech.
If you are looking to throw together your own inverter, a possible IC for the job is the MIC4826 and with supporting components would only cost a few bucks. Looking at the datasheet and assuming a 3V input, it looks like you should be drawing ~30mA, although you will to test for your specific sheet. A CR2032 carries 220mAh so you should be able to get ~7hrs of runtime.
One of the things I tell my students is that it is GOOD to ask questions. And when you don’t know the answer to one posed to you, it is OK to say “I don’t know.”
On that note, I have been scratching my head over formulating a proper response to David’s question and thought “why don’t I ask our readers?” You all give great feedback and I am sure that there is someone out there that can help. If you think you have an answer, post in the comments section, and I will compile a response based on the feedback we receive!
What is the best path if you want to progress from Arduino to bare AVRs? There seems to be a range of toolchains of varying currency around so google requires a lot of digging to find if what you have is actually current. Ditto some ICSPs seem to have no windows 7 support which can be a trap if that’s your OS of choice. Another way to word the question would be ‘what is the easiest way to work with AVRs while still being able to use things like the internal oscilator and timer interupts’?
Thanks everyone and I look forward to your responses!
Don’t forget, everyone is invited to ask a question!
Photoduino’s firmware version 0.10 was released to include the ability to control a solenoid valve and automatically generate drops with Photoduino.
Solenoid valves are typically powered through 12VDC and have a high current consumption, so we need this new circuit to be connected to Photoduino’s DEVICE port so it allows the connection to a solenoid valve and a 12VDC power supply.
The control of the valve is performed by a Mosfet IRL520 logic transistor and the circuit also includes a 1N4004 diode to prevent the reverse current that is accumulated in the coil.
The board is designed in a single sided PCB so it is quite easy to make at home, but it is also available for purchase as a kit which includes a solenoid valve, a 60 ml syringe and a 12VDC battery holder.
The 12V needed to feed the solenoid valve can be supplied by the 8xAA (R6) battery holder included in the kit. You can also use a 12VDC with at least 500 mA current (not included).
Here you can find my latest project a six IV-11 vfd tube clock designed in a
simple format using Atmega168 and MAX6921. It is a design came after
studying other vfd tube clocks including yours Ice Tube Clock.