New member of the WS2812 family

8mm_led_shield

cpldcpu writes:

What’s pretty cool about these LEDs is that they are diffuse – no more blinding unidirectional light. This might be very useful for indicator lights. Furthermore, you can easily wire them freeform without a pcb. I see a lot of RGB LED cubes coming up…
The LEDs come with four leads: VCC, GND, Data in, Data out. Instead of the thin bendy leads that I am used to from normal RGB LEDs, they come with with thick, rigid, pins which can not easily be bent arbitrarily. This could be a measure to improve heat sinking, but is a bit annoying when working with these LEDs. The data sheet states that the pitch of the pins is 2.54 mm. Strangely enough they do not quite fit into a normal protoboard, it seems that the real pitch is slightly smaller (2.5 mm?).

Sound pressure level meter (SPL) dB audio meter using AVR ATmega

splmeter_atmega_01

Davide Gironi  has written an article detailing a simple sound pressure level meter (SPL) dB audio meter using AVR ATmega:

What is proposed here is a SPL db meter using and AVR Atmega micro.
A sound level meter or sound meter is an instrument which measures sound pressure level. Sound pressure level (SPL) or sound level is a logarithmic measure of the effective sound pressure of a sound relative to a reference value. It is measured in decibels (dB) above a standard reference level. The commonly used reference sound pressure in air is = 20 µPa (rms) which is usually considered the threshold of human hearing. Keep in mind that 1 pascal will equal an SPL of 94 dB. Because the frequency response of human hearing changes with amplitude, a weighting have been established for measuring sound pressure. Usually the A-weighting curve is used. A weighting curve is a graph of gain across the frequency range (10Hz to 20kHz).

Open Bitcoin ATM

Open-Bitcoin-ATM

Check out the world’s first open-source Bitcoin ATM:

Open Bitcoin ATM is the worlds first open-source automated teller machine for education and experimentation.
Want to make one? Here’s a step by step tutorial. It takes about 7 – 10 hours to build with simple tools. Cost of components are less than $500 new but used parts can be purchased for even less on eBay.

Via Hacked Gadgets.

Continue reading “Open Bitcoin ATM”

Digitally controlled HiFi Amp with 4 way mixer

Michael shares his project files for a digital HiFi amp featuring a 20 W stereo power amplifier, 4 way audio in and digital volume control interface.

Though I am a musician I don’t care for calling an expensive hi watt stereo my own. For years I have used a homebuilt stereo amplifier built around the TDA1554Q IC (basically just this chip in a nice box) and I am still very happy with the sound quality. This amp serves as a computer desk sound system, which acts as a radio/movie sound system as well.

In the meantime the number of sound sources that I want to connect to my “stereo” has increased … suddenly there was a tablet that I use as an internet radio, a music player demon that runs on a raspberry pi and from time to time I want to listen to a podcast that I downloaded to my smartphone.

So a next-gen desktop stereo should have multiple inputs … about four of them would be nice. Also when watching TV on my computer from the bed I don’t want to get up all the time if I just want to adjust the volume. I’d like to do it digitally … maybe use my smart phone as a remote control?

For project details and to download the open source project files visit Michael’s acidbourbon’s blog.
Via the contact form.

Autonomous iPad playing robot

playing_robot

Tom Randle made this robot that automatically plays Leap Sheep on the iPad:

On a complete whim about 2 years ago, I decided to make a robot to autonomously play one of my favourite iPhone games: Leap Sheep. The game’s nice and simple so lends itself really well to automation. Sheep run from left to right, and to play, all you need to do is tap them before they crash into the fence.

Time plotting clock

Time-Plotting-Clock

A clock that plots time:

The Time Plotting Clock mechanism is fantastically simple, 3 tiny servo motors allow the erasable marker to be moved along the drawing surface and raised when no contact with the surface is desired. This allows the pen to write the time. There is also a tiny eraser located in the upper right corner, when the next minute is ready to be drawn the pen grabs the marker and erases the previous time before drawing the new time.

Via Hacked Gadgets.

Check out the video after the break.

Continue reading “Time plotting clock”

#FreePCB via Twitter to 2 random RTs

probecable-yellow

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.

Custom Clothing in Shenzhen

By akiba

One of the less commonly known features of Shenzhen is the clothing mall at the top floor of the Luohu shopping center. It’s an interesting place because you can get almost any type of clothing made there. Those that know me know that fashion sense is probably one of the last things on my mind. But I heard so much about this place that I figured I might as well give it a shot. When I was doing the MIT Media Lab Shenzhen tour with Bunnie, we had a precious free day where nothing was planned. A bunch of us decided to go check out the clothing mall in Luohu just to see what it was like. When I arrived, it was much different than I expected. There were bolts and bolts of fabric crammed into narrow aisles. There were colors, textures, types, many of which I’ve never heard of. It was kind of overwhelming and I originally hadn’t planned to get anything made. My first instinct was to point to a friend’s jacket and I told them I wanted an exact replica. It was mainly to test the quality of the tailors to see how much detail there’d be where I could compare it to the original. As I walked through the aisles, a bolt of fake fur caught my eye. “This was my chance!” was the first thought that came to mind. I didn’t quite realize it, but I seemed to secretly harbor a desire to own a faux fur coat. It was at least much more exciting than getting a replica of a friend’s jacket made. I decided to pull the trigger and get the coat and it turned out much, much better than I could have hoped for. I even installed LEDs inside it (also from Shenzhen) and wore it to a few events around Tokyo. Eventually, the jacket became quite popular and would get passed around from person to person so they could take pictures with it on. I would randomly see the jacket on twitter being retweeted by friends of friends. Ha ha ha.

Via Hacker Camp Shenzhen mini-site: Custom Clothing in Shenzhen

Turning your Flash Destroyer into a clock

IMG_3064

voidptr writes:

So ! …. 2 years later, here an update on living with my dangerous Flash Destroyer hack ! First off, front and back picture :o)
I added few things since its birth …
A battery for the real time clock, really handy when you reprogram code and you don’t want to lose the current time …
4 buttons who are routed to the bottom left header, and who connect to the IO chip with green jumpers.
Some kind of feet, printed on my Prusa2 clone :o)
So what is it life since 2 years ??
well this is my principal clock on my desk and I use it from time to time has a prototype board.
So it turn out pretty handy and I still love the look, (and the weird look of people looking at it) :o)

ATtiny LED driver for an RC car

top

joeforker posted his ATtiny LED driver for an RC car in the project log forum:

I thought I’d share a little board I’m making to add headlights to a model car. The board is a little 1″ square thing with mounting holes. The top right contains a constant-current driver built from a BC847 BJT, a 2N7002 MOSFET and a current set resistor “the Instructables circuit”, “Power LED’s – simplest light with constant-current circuit”. I hope to have overkill-bright headlights by passing 100-200mA through these devices; hope they don’t get too hot. I’ve added a trimpot to be able to reuse the board as an adjustable current source and, rather than tie the MOSFET gate to +, it’s tied to a pin on an ATtiny. The micro will be able to switch the light on and off based on a signal from the receiver (the left header). The bottom of the board contains a LDO and a JST-XH header that will connect directly to the balance plug of the car’s 2S LiPo battery.

Via the forum.

Picberry: R-Pi / Allwinner A10 PIC programmer using GPIO connector

picberry_iteaduinoplus
WallaceIT has developed a Raspberry Pi / Allwinner A10 PIC Programmer using GPIO connector. “It currently supports dsPIC33F and PIC18FxxJ families, though other “code-programmed” families can easily be added. Feel free to use and comment it! Any feedback will be appreciated!”

Via the contact form.

RetroWatch, an open source smart watch project using Arduino and Android

FFY7O78HRPNAA95

Here is a very nice build of a DIY smart watch based on Arduino and Android by godstale. Check it out.

But here is a simple way to evaluate smart watch’s future on your own. Make it! With Arduino micro-processor and Android, I made a simple smart watch and named it “Retro Watch“. You can do this too!
Retro Watch is an open source project to let you make a smart watch based on Arduino and Android.

Networked 1D Pong

DSC_0441-1024

phalox decided to build his own version of 1D pong with the TCP/IP stack:

Not just being a copycat, I really had to add a bit of extra mustard. In this case an entire TCP/IP stack! This results in a network connected 1D Pong game, in which you can have as many nodes (players) as you would like.
It was another fun experience… writing a driver for the WS2812, getting our stack integrated on these wifi boards (you can’t just make your own wifi driver because Microchip doesn’t even provide a decent data sheet for the wifi chips), designing a UDP protocol, learning that decentralized behaviour is really not that easy…
Comments are welcome as always!

Via the project log forum.

Why Do I Need A Calculator?

By akiba

Desktop_calculator_W-120CL

I’ve been getting some questions on why a calculator is included in the hackercamp package. There’s actually a pretty interesting story behind it. A lot of people new to the electronic markets in Hua Qiang Bei quickly realize that no English is spoken there. Bargaining is carried out in Chinese and you actually have to have a good mastery of the number and counting systems. A good dose of humor is also always appreciated. Actually, if you watch closely, the pros in the market will mainly use hand symbols to indicate numbers and price and the transactions almost look like they’re in sign language.

Bargaining is kind of a game at a lot of the Chinese markets and if you only speak English or a non-Chinese language, then many of the vendors will either refuse to bargain or not engage with you at all. The process of translation, looking in a dictionary, or trying to decipher meaning on both sides is a frustrating experience and interrupts the natural rhythm of a sales transaction. A lot of the vendors are busy, taking care of children (yes, the markets are also like a huge daycare), or are simply not making enough margin on their products to bother with the additional frustration of language barriers.

One way to get around that is to carry around a large calculator with a big display. Almost all of the vendors will have a large desktop calculator and they’ll use it to calculate the unit price of the components you want to buy, multiplied by the quantity. Finally, they’ll turn it around to indicate the price you need to pay. It’d be considered rude to use their calculator to bargain, but if you have your own calculator, you can punch in your own price and show it to the vendor. This puts you on more of an equal footing with the vendor and removes the immediate need of hand signals or translating the pricing. Ian put a lot of work into researching this method of sales transaction and bargaining, which is probably the easiest way to go for non-Chinese speakers new to the market. That’s also the reason why we’ll be providing calculators in the package. You can use it to calculate per unit prices, convert price to other currencies, etc. They’ll be the desktop calculators with a large, easily readable display and once you have it, you can get into calculator battles with the vendors in HQB :)

Akiba

Via Hacker Camp Shenzhen mini-site: Why Do I Need A Calculator?

Free PCB Sunday: Pick your PCB

STICKERS

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: Driving LEDs with Xilinx CPLDs

XAPP805

Here’s Xilinx app note on using CPLDs to perform the same functionality as those common LED driver chips.

Light-Emitting Diodes (LEDs) are commonplace on the modern day Printed Circuit Board (PCB). Whether they are indicating status, activity or some other function, they need to be driven by a device that can provide sufficient current to illuminate them. Traditionally, LED driver devices have been used for this purpose, but this application note aims to demonstrate how that functionality can be incorporated into Xilinx CPLDs to save both cost and valuable board space.

App note: Using a microprocessor to configure Xilinx FPGAs via slave serial or selectMAP mode

XAPP502

Great app note from Xilinx on configuring their FPGA through slave serial and parallel selectMAP mode

This application note describes a technique for configuring an FPGA from an embedded processor. Three common components are required: an embedded microprocessor, some non-volatile memory, and a CPLD. Cost, as well as real estate, can be reduced if the function of a dedicated configuration device, such as a PROM, can be integrated within these three components.
Note: Some systems might not require a CPLD if the microprocessor has a sufficient number of general-purpose I/O (GPIO) pins available. For these systems, the Xilinx FPGA can be configured directly by the microprocessor.

App note: Choosing the right transformer with the MAX13256

5766Fig01

Here’s an application note from Maxim describing how to specify a transformer that meets your application needs:

The MAX13256, a 10 Watt transformer driver, is an improved way to convey power across isolation boundaries. As with all transformer drivers, good system performance requires good transformer specification. Though many transformers can potentially work with the MAX13256, not all transformer data sheets are specified with a transformer driver application in mind.