Say hello to the new server!

in site by Ian | 21 comments


If you can see this post you have reached the new server! Please report any problems you experience. We’re now running on Varnish and some cached stuff may need tweaking before it runs smoothly.

We will post the full setup of the server next week.

Posted in site | 21 Comments

BT-C3100 intelligent battery charger teardown

in Teardowns by DP | 19 comments


Alan Parekh of Hacked Gadgets writes:

Thanks to GearBest for sending in this Opus BT-C3100 V2.0 Intelligent Battery Charger for review. at a quick glance this charger might look like any other charger that you see at the grocery store.  Your generic store bought brand probably also has 4 charging bays for AA and AAA batteries, it probably has 2 charging circuits which places 2 cells in series to charge them, it most likely has 2 charging lights which just turns off when charging is done. If you leave the batteries in your generic charger you will most likely have batteries that have been overcharging or running down. Also your generic charger can probably just charge one chemistry of battery.

When you have a closer look at the Opus BT-C3100 V2.0 Intelligent Battery Charger you can see how this system differs from your every day generic battery charger. It can auto detect and charge NiCd, NiMH and Li-ion batteries. It charges each cell independently preventing bad cells from interfering from other cells from charging properly. Forget charging lights, this has a full LCD display that provides tons of status. It will monitor batteries that are left in the charger and keep them topped up and ready to go. From here the features go on and on. Don’t let the small package fool you, there is a ton of smarts and features built into this small package.
Have a look at the pictures below and in the video for a look inside the charger. The construction is a dual sided SMD load, the construction looks very professional. The battery contact spring tensioners work well and the connection to the PCB has been beefed up with a thick metal bar…

Via Hacked Gadgets.

Check out the video after the break. Continue reading →

Posted in Teardowns | Tagged , , | 19 Comments

BridgeDuino: A wireless Arduino HUB and shield

in Arduino by DP | 2 comments


TechBitar shared his latest project the BridgeDuino with boards from DirtyPCBs:

BridgeDuino is a Swiss army knife PCB for rapid networking of inexpensive wireless communication modules. Breadboards are super for one-off experiments. But after prototyping half a dozen wireless prototypes involving more than just two Arduinos, the wiring mistakes and associated debugging grew more time consuming.
I also wanted a PCB that can act as a shield to Arduino Uno as well as work with the inexpensive and low-power Arduino ProMini.

As of this release, BridgeDuino supports the following wireless technologies/modules:
IR Transmiter LED 940nm
IR Receive 38Khz
RF433Mhz Receiver
RF433Mhz FS1000A Transmitter
Bluetooth HC-06 & HC-05

Via the contact form.

Check out the video after the break.

Continue reading →

Maker Villa Penang introduction

in #liveupdates by Ian | 1 comment


William @ SGmakers threw a Hacker Villa in Penang Malaysia after attending (and sponsoring) Hacker Camp Shenzhen. We got to attend the first two days full of hacks, food, and making new friends.

Penang is an island, and UNESCO world heritage site, just off the coast of Malaysia. Its renound for street food, a mix of Indian,Malaysian, and Chinese, rivaled only by that of Kuala Lumpur.

Day one introduction closed at a bar in the world heritage area after a screening of the Maker Movie, followed by a share your hacks session.

Continue reading →

Posted in #liveupdates | 1 Comment

Monitoring Android traffic with Wireshark

Ever wonder what data is being sent out by your Android device? Here’s a post from LinuxJournal outlining how to monitor your device’s WiFi traffic. The technique involves setting up a man-in-the-middle Wireless Access Point (WAP) on your Ubuntu Linux box, then connecting your Android device via WiFi to this point. Wireshark is then run on the Linux box to sniff the Android traffic.

Via LinuxJournal.

#FreePCB via Twitter to 2 random RTs

in Free PCBs by DP | 0 comments

irtoyv3 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.

Guitar booster pedal (MPX-1)

in DIY by DP | 0 comments


Bastl3r  wrote this instructable detailing the build of his guitar booster pedal project:

I chose an overdrive pedal design off of (Schematic) and modified it like this:

  • added a simple positive/middle/negative supply
  • added a noise filter I found on right after the DC Jack (Huminator)
  • took away the clipping diodes on the output
  • connected the diodes in the feedback path directly
  • added the switch to change the resistance of the feedback path (10k <->30k)
Posted in DIY | Tagged , | Leave a comment

Burn c into other chips using Arduino Duemilanove

in Arduino, project logs by DP | 2 comments


Kathy Yang writes, “We may often encounter such situation as bootloader falls off when using Arduino, this thing can freak us out especially when we got no bootloader tools on hand. So what shall we do? Here we’ll introduce a way on how to burn c via Arduino, which is rather practical in cases when without bootloader burning tools and no extra Arduinos.”


Via the project log forum.

A 5c lithium ion battery charger

in how-to by DP | 40 comments

5cCharger (1)

Nerd Ralph writes:

As various sites explain, lithium-ion rechargeable batteries should be charged to 4.2 volts. USB ports provide 5V, so all I needed was a way to drop 5V down to 4.2 or less. Standard diodes have a voltage drop of 0.6 to 1.0 volts, so I pulled up the datasheet for a 1n4148, and looked at the I-V curve
A standard USB port should provide up to 500mA of current, enough for charging a small camera battery. A fully-discharged li-ion battery is 3V, and will climb to 3.8V within minutes of the start of charging. Line 2 in the graph indicates a 1.2V drop at 350mA of current. Under load the voltage output of a USB port will drop a bit, so with 4.9V from the USB port and 3.8V drop at the battery, the charging current will be around 250mA (where 1.1V intersects line 2). Looking at the numbers, a single 1n4148 diode would work as a battery charge controller.

Posted in how-to | Tagged , , | 40 Comments

Proximity sensing LEDs

in DIY, LEDs by DP | 9 comments


Here’s a proximity-sensing LEDs project by Will_W_76.  He writes a complete step-by-step instructions here:

So how does this all work? What makes it proximity-sensing? Remember in the explanation above that the photo-transistor acts like a switch. So when the photo-transistor is off, no current is flowing across it to our blue LED and the LED is off as well. Now look at the other side of our circuit. That’s where the IR LED is connected, and it is connected such that it is always on and emitting 880nm infrared waves. Remember that I also mentioned the photo-transistor is set to respond best to wavelengths of 880nm? That’s how the proximity-sensing works! When an object (such as your hand) goes over this little “cluster”, IR light of 880nm is emitted from the IR LED. This light reflects off of your hand and back to the circuit. When the photo-transistor picks it up, it turns on allowing current to flow through from the source to our blue LED lighting it up!

Posted in DIY, LEDs | Tagged , | 9 Comments

DirtyPCB Charliecube

in Arduino, project logs by DP | 0 comments

PCB_2 -dirtypcb

kjetilei shared his Charliecube project, inspired by the instructions provided by SobiGuy at SobiSource:

I showed the cube at my local makerspace and proposed a build day. The interest was high enough to bulk order the various items needed for 10 kits.
Just before ordering the batch of protoboards I started to think about making a proper PCB instead of the protoboard and the dreaded rats nest. I checked the pricing at DirtyPCBs for black 10×10 boards and was thrilled to see that the pricing was only a bit more expensive than the protoboard and all needed extras.
Fritzing was fired up and after a couple of looong evenings hand routing the paths (for semi decent apperance) I was ready to order.

Since the dirty in DirtyPCBs imply that the quality is not the best I hoped for a great result but was ralistic and knew that I could receive PCBs that looked worse than I hoped for. However the PCBs I received where great! Thanks Ian for making this possible!

Via the project log forum.

App note: Unique and novel uses for ON Semiconductor’s new One-Gate family

in app notes by DP | 3 comments


One-gate logic uses and their benefits application note (PDF) from ON Semiconductor.

One–Gate logic devices have been in use for several years, and are nothing more than single–gate derivatives of their multi–gate cousins. Traditional ICs were packaged in 14 and 16 pin Dual–in–line Packages (DIPs), and the goal of the IC manufacturer was to get as much functionality as possible into a single–package device. Double, triple, quadruple, and quintuple versions of simple logic functions became the norm. Often there was not enough room to add an additional logic element on the chip and still keep the board size small. The designer was faced with having to re–design the entire chip or to add additional IC components to the board layout to accomplish the required task. A solution to this dilemma was to use One–Gate designs, initially offered in the SOT–23, 5–pin package, and later in the even smaller SOT–353 (SC88A). The latter package takes up only 4.2 mm 2 of board space, and less than the area of a TSSOP–20 pin device. One–Gate products, now fabricated in a .6µ advanced high–speed CMOS technology, are very fast, with < 4 nsecs gate delays, and enough drive (8 mA) to support most typical applications. The package is so small, that it fits “in–line” with the trace that it is mounted on.

Free PCB Sunday: Pick your PCB

in Free PCBs by DP | 72 comments


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 →

Posted in Free PCBs | Tagged | 72 Comments

App note: Ambiguity of the peak power rating of TVS devices

in app notes by DP | 1 comment


Here’s a tip app note (PDF) from ON Semiconductor on selecting specs for an TVS diode.

There are two important properties of a TVS device during an electrical stress. The TVS must be able to self-protect and survive the stress current, and the TVS must clamp the protected line to a low voltage during the stress. Power ratings of TVS devices do not provide a good measure of clamping effectiveness because this metric is artificially enhanced by a higher, less desirable, clamping voltage. It is true that TVS devices with high peak power ratings are often larger diodes and may therefore also have low dynamic resistance and low clamping voltage but there are exceptions, and one such exception has been highlighted in this note. It is therefore important to always consider the dynamic resistance or the clamping voltage at specific currents levels, rather than focusing solely on the peak power rating when selecting a TVS device.

App note: Sorting through the low voltage logic maze

in app notes by DP | 0 comments


Here’s how to guide (PDF) from NXP in choosing the right standard logic from various choices that fit your application.

Digital systems are running at faster speeds, operating at lower voltages, and they are becoming more highly integrated. Many functions can be integrated into FPGAs or ASICs, however, this does not mean that generic standard logic has gone away. Designers may choose to design with standard logic for the following reasons:

•The need for cheap, simple fixed functions with high speed and lower power consumption
•Space constraints requiring small packaging
•Bus driving capability
•Interfacing between mixed voltage systems
•Need for hot insertion capability
•Need for bus switching.

App note: Low Voltage Agile I/O GPIO Input/Output Characteristics

in app notes by DP | 0 comments


App note (PDF) on NXP’s Agile I/O expander, discussing its capabilities and how to use it efficiently.

I2C-bus GPIO devices are widely used and expand a control processor’s pins to 8-, 16- or 24- bits of general-purpose input or output. The characteristic of these I/O needs to be accurately known to efficiently use them in a system. This application note will explore the actual electrical characteristics of Agile I/O GPIO pins.

DIY 60W adjustable electrical load

in DIY, power supply by DP | 0 comments


DIY 60W adjustable electrical load project from Electro-Labs:

In this project, we are building a useful board which should take place on your bench. It is an adjustable electrical load which can sink up to 5A @ 60W continuously. This board will come to aid when you need to draw an exact amount of current from a supply. For instance to learn the current rating of a power supply, measure the heat dissipated on a circuit element, discharge a battery etc.
The electrical load lets you monitor the current by using the ampermeter on it. A multiturn variable resistor is used to set the current precisely. The circuit is powered by a 15V-18V power adapter. A large heatsink on the board helps dissipating the heat generated on the MOSFET which is the main component used for limiting the current.

A four channel remote control using EnOcean Pi

in R-Pi by DP | 0 comments


four-channel remote control built using the EnOcean Pi by Kerry Wong:

In my last couple of blog posts, I did a brief overview of the EnOcean Pi sensor kit from Newark and demonstrated how to compile and run the example code using a Raspberry Pi. In this blog post, I will show a real world example – a four-channel remote control built using the EnOcean Pi in conjunction with the EnOcean pushbutton module.

Check out the video after the break.

Continue reading →

Tutorial: GNU Radio with the HackRF SDR

HackRF One
Michael Ossmann, one of the developers of the amazing and affordable HackRF SDR transceiver, is releasing a tutorial series on using GNU Radio. “This ongoing video series will be a complete course in Software Defined Radio (SDR). In this course, you’ll build flexible SDR applications using GNU Radio through exercises that will help you learn the fundamentals of Digital Signal Processing (DSP) needed to master SDR. For the over-the-air exercises, you’ll need a HackRF One or other SDR peripheral.”

The tutorial series can be found on Michael’s GreatScottGadgets site.

(Note that the HackRF SDR featured in this series, while costing considerably more than a $20 RTL-SDR dongle, covers a greater frequency range and includes a low-power transmitter. Still, at around $300 it falls in the budget of more hackers than the $1000+ USRP Ettus series.)