Playing With An Oscilloscope You’ll (probably) Never Own

We’ll have to admit that we were really jealous when [Shahriar] sent us a video he made, in which he casually explains how a $500,000 160GS/s 62GHz oscilloscope works and then starts playing with it.

Even though you need to be quite familiar with electronics to fully understand the oscilloscope’s inner workings, [Shahriar]’s step by step explanation is still approachable for those who only understand the basics.

In the first half of the video he uses the manufacturer’s documentation which contains the oscilloscope block diagrams, so you’ll also learn about:

  • timer interleaved Analog to Digital Converters (ADCs), which allows you to increase your input sampling rate by using several of them
  • phase-locked loops, which use a reference clock to generate a much faster clock signal
  • custom made dies and the materials used for high frequency electronic components

In the second half of the video [Shahriar] connects a pseudo random binary sequence generator and uses the oscilloscope to make several measurements that you’d typically want to know for high speed signals (jitters, eye quality factor…). He later performs a small experiment where he up-converts the frequency components of two random 3.12Gbit/s signals and tries to recall each original signal using the oscilloscope functions, making this part of the video a bit harder to keep up with.

Designing A Pressure Sensitive Floor

ccm_activefloor8

[Sean] and his team at Adobe were asked to build “something new” for the Children’s Creativity Museum in San Francisco, so in several months they managed to build a digital/physical environment for kids called “Sense It”.

Part of this project involved designing and building a pressure-sensitive electronic floor which could detect if children were sitting, walking or running. As a camera based detection system couldn’t give them the type of precision they wanted, [Sean] decided to use pressure-sensitive resistors placed under MDF panels.

There are a total of twenty-one 2’x4′ tiles, each one including 8 pressure-sensitive resistors and an ATtiny84 based platform. All the microcontrollers digitize their 8 sensor signals and send their conversion results to a beaglebone over a shared i2c bus in a RJ45 CAT5 cable. As it is [Sean]’s first project, we will cut him some slack but several design mistakes have been made in our opinion:

  • Using i2c instead of RS485 / CAN for long distance data transmission
  • Digitizing the sensor voltages so far from them, as noise is added before the ADC
  • Sending the +5V required by the ATtiny in the RJ45 cable instead of a higher voltage (which would involve putting an LDO on the platforms)
  • Separating the digital and analog ground planes as the platform current consumption is low and transmission speeds slow

But the children who can now play with the complete system certainly won’t care. And you… what do you think of [Sean]’s work? Don’t hesitate to let us know in the comment section below.

Hacking Transcend Wifi SD Cards

[Pablo] is a recent and proud owner of a Transcend WiFi SD Card. It allows him to transfer his pictures to any  WiFi-enabled device in a matter of seconds.

As he suspected that some kind of Linux was running on it, he began to see if he could get a root access on it… and succeeded.

His clear and detailed write-up begins with explaining how a simple trick allowed him to browse through the card’s file system, which (as he guessed correctly) is running busybox. From there he was able to see if any of the poorly written Perl scripts had security holes… and got more than he bargained for.

He first thought he had found a way to make the embedded Linux launch user provided scripts and execute commands by making a special HTTP POST request… which failed due to a small technicality. His second attempt was a success: [Pablo] found that the user set password is directly entered in a Linux shell command. Therefore, the password “admin; echo haxx > /tmp/hi.txt #” could create a hi.txt text file.

From there things got easy. He just had to make the card download another busybox to use all the commands that were originally disabled in the card’s Linux. In the end he got the card to connect a bash to his computer so he could launch every command he wanted.

As it was not enough, [Pablo] even discovered an easy way to find the current password of the card. Talk about security…

A Crystal Radio Amplifier In A Jar

The cool thing with crystal radios is that they are solely powered by the incoming radio waves. However, it usually means listening to your AM radio station with an earpiece and even then, depending on the antenna length, ground connection, and radio station, it can be quite hard to hear.

Even though it is cheating, [Steven] decided to make an amplifier for all the different crystal radios he had made over the years. His design, based on an LM386 amplifier was firstly tested on a breadboard and then permanently soldered onto a perfboard. To make the complete system easy to transport, he opted for a peanut butter jar where he embedded the speaker in the cap. The on/off switch and volume controls are mounted on the side, and easy alligator clips are used for the antenna connection.

The final result is not the one shown in the picture above as [Steven] painted the jar black, giving it a sweet look.

Building The Electronics For A Tesla Coil… And Watercooling Them

A few years ago [Patrick] was offered the Tesla coil of a friend of a friend. This was an opportunity too good for him to pass up.

He then began the creation of an Off-Line Tesla Coil (OLTC), where no supply transformer is used. The incoming mains supply is rectified and directly fed into the tank capacitor.

[Patrick] therefore had to build a huge capacitor bank and more importantly his own primary coil, made with a 1.6mm (0.064″) copper sheet to handle the immense current involved. Air cooling the electronics was sufficient until he started using his three phase input supply. As more power involves more heat, a waterblock was designed to cool the main transistor.

Patrick’s write-up is very detailed and worth the read. Once you’re finished with it, we advise you to browse through his website, where a lot more cool projects are described.

Tiny WiFi Modules, Again

The CC3000 is a tiny, single-chip component that adds all the necessary hardware (save for a chip antenna) and software to get even the most minimal microcontrollers onto a WiFi network. It was announced early this year but making proper breakout boards takes time, you know? This time has finally arrived with CC3000 modules from Adafruit, and evaluation modules and booster packs from TI themselves.

Unlike other microcontroller-compatible WiFi modules out there, the CC3000 takes care of just about everything – the TCP/IP stack, security stuff, and even the configuration with TI’s SmartConfig app for desktop, laptop, or mobile devices. Realistically, you can get an ATtiny, an exceedingly sparse microcontroller, or even a Commodore 64 or Apple II on the Internet with this. It’s very, very cool.

While these breakout boards and modules are priced very well for what they do, they’re still fairly expensive to stick in a project permanently. Where the CC3000 really shines is including it in your next fabbed board. There are already Altium parts and an Eagle library that includes this part should you need help with that, and blatant advertising for our overlords at SupplyFrame if you’re looking for a source.

A $5 ARM Development Board

Most of you know that there are plenty of ARM powered development boards out there, so you may not be really sure what a new one can still bring to the table.

With a $5 price tag, the open hardware McHck (pronounced McHack) is meant for quickly building projects on a small budget. The board created by [Simon] is based on a Freescale Cortex M4 microcontroller, and can be plugged directly into one’s computer. As a Direct Firmware Update (DFU) bootloader is present on the microcontroller, there is no need for external programming equipment.

The board has unpopulated footprints that allow users to add other functionalities that may be required for their future projects: a Real Time Clock (RTC), a Boost regulator for single cell battery operation, Buck and linear regulators, a Lithium Polymer (LiPo) battery charger and even an External Flash storage.

The Bill of Materials can be found on the project wiki and the McHck community will soon launch a crowdfunding campaign to send the 5th version of the board to all the hobbyists that may be interested.

And if you’re curious, you can also have a look at all the other boards that Hackaday featured these last months: the browser based IDE arm boardquad-core ARM dev board and the Matchbox ARM.