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21 Jul 2011

Choosing USB Pin Voltages for iPhones and iPads @ Voltaic Systems [via]

We continually make minor tweaks to the USB output of our batteries to make sure we charge as many devices as possible. We pay particular attention to Apple products and now, with the introduction of the iPad, it has become slightly more complicated to have a one size fits all solution. This post tells you the Voltage on each pin of our USB batteries, which is hopefully useful if you’re trying to make your own USB charger. There are lots of different threads Apple charging, but we’re going to focus here on USB pin Voltages as this was the variable we were adjusting in this round of production.

Choosing USB Pin Voltages for iPhones and iPads - [Link]

14 Jul 2011

swharden.com writes:

I developed a nifty way to send data from any microcontroller to any PC running any operating system with zero components and hardware you probably already have sitting in front of you.  Traditional interface methods (namely serial port and usb port, both have been referenced on Electronics-Lab) have drawbacks. For serial, you need a level converter IC (like a max232) and an archaic PC with a serial port, or a USB serial port adapter (many of which don’t run on Linux or newer versions of windows), and a crystal specifically chosen for transfer at a certain bit rate. FTDI makes a series of USB/serial interfaces, but they’re expensive and SMT only I don’t feel like paying even more for a breakout board just to communicate with a $1 microcontroller. Also, many ATMEL chips (most of the ATTiny series) don’t have rs232 capability built in, so you have to bit bang it in software (not fun). USB is another option, but requires a crystal and some level conversion circuitry, and isn’t supported by most small/cheap ATMEL chips. It’s built in some simple PICs (like some of the 18F series) but I don’t want to switch architecture just to send a few bytes to a PC! The V-USB project helps ATMEL chips bit-bang the USB protocol, and I’ve gotten it to work, but it’s not easy (their hello world program is hundreds of lines of code), and you have to mess with writing USB drivers or interfacing pre-made USB drivers with OS-specific solutions, it’s not fun either.

I’ve long wished there were an easier way! In this post, I demonstrate a simple way to send data from a microcontroller to a PC (and a more advanced second example showing bidirectional communication) using PC a sound card! Although the one built in most PCs would work, I decided to do it with $1.30 sound cards that are all over eBay. The chip sends pulses of data to the PC and a Python script (which can be run on virtually any OS) listens to the sound card with the pyAudio library and waits for data. When it’s received, it measures distances between pulses and dumps data values to the screen (optionally logging them to a CSV file ready for graphing by Excel or some other program).  A series of calibration pulses precede the data stream allowing the PC to adapt to incoming data at any speed (no specific clock speed or crystal is required).

Although it’s not a refined method suitable for consumer applications, it sure is a useful hack for anyone looking to quickly exchange data between a microcontroller and a PC!

Sound Card Microcontroller / PC Communication - [Link]

4 Jul 2011

Ian and Kevin from Nonolith Labs write:

Our open-hardware startup just announced our first two projects, both of which are vaguely bus-pirate related. The CEE is a USB analog multitool. It can source and measure voltage and current on two channels, making it a mix of a power supply, multimeter, function generator, and oscilloscope. It’s in its very early stages, with our alpha board up at Github.

Our second project started out as a browser-based frontend for the CEE, and rapidly evolved into (what we’ve found to be) a flexible, versatile way to display data and control hardware. It’s built in Python and Javascript – out of the box, we support Firmata(on the Arduino) and the Bus Pirate’s pins as digital IOs. Our API documentation, an in-browser demo, and our Github page are linked right off of our Pixelpulse page. Check it out, and let us know what you think!

Nonolith Labs CEE USB analog electronics multitool - [Link]

29 Jun 2011

Oleg writes: [via]

What started as a quick re-factoring effort transformed to a major redevelopment, but finally all pieces fit together tightly and I am pleased to announce that initial release of USB Host Shield library ver.2.0 has been posted to github.

Some of the major improvements include the use of only 5 Arduino pins, 3.5x faster low-level transfers, and the ability to use USB Hub(s).

Make sure you stop by Circuts@Home to check out the full details like the current/future supported device classes and supported hardware versions .

USB Host Shield library Version 2.0 – [Link]

15 Jun 2011

PocketPico Picoammeter is a new, USB-connected; very low current measurement device for DC current from 20pA to 2mA. Tiny (2.7” × 1.4” × 3.7”), lightweight (8oz) PocketPico Picoammeter eliminates harmful switching spikes and reads at a rapid 15,000 samples per second. Perfect for lab test setups, PocketPico Picoammeter’s high accuracy, fast speed, and single measurement range brings new features previously unavailable in other picoammeters, like small size, single 20pA – 2mA measurement range at 15,000 Sa/s, high accuracy (±0.5%) and resolution (4½ digits), protection against voltage transients, etc.

PocketPico Picoammeter is dedicated to the task of measuring very low electrical current in optoelectronics, ion and electron beam monitoring, materials resistance testing and more. When connected to a PC, PocketPico Picoammeter accurately measures current from 20pA – 2mA and displays it using the free Windows-compatible easy-to-use PocketPicoReader software on the PC’s display.

PocketPico Picoammeter is one of the easiest and most affordable ways of measuring a wide range of extremely low current. Simple to integrate with existing lab tasks, it avoids using bulky equipment simply to take low power measurements, especially for field use. PocketPico Picoammeter could potentially save users thousands of dollars on instrument costs, software licenses and expensive data acquisition equipment.
Applications for PocketPico Picoammeter include: photodiode current and dark current measurement, ion beam monitoring and measurement, SEM and TEM beam current measurement, optical fiber alignment, component, sensor, and device I-V characterization, materials resistance testing, leakage current testing, analog and mixed-signal circuit testing & analysis, teaching labs, product demonstrations, etc.

Saelig’s New Tiny Picoammeter Eliminates Voltage Transients – [Link]

14 Jun 2011

adafruit.com writes:

A logic analyzer is a device that lets you watch digital signals in your electronics project. You can watch them real-time or log the data for later perusal. Unlike an oscilloscope, its not good for measuring analog signals – but also unlike an oscilloscope, you can track 8 signals at time! So its a good complementary tool. This logic analyzer plugs into a computer and has easy to use, cross-platform software. This makes it small, portable and inexpensive.

If you ever have to to debug SPI, i2c, serial, CAN, 1-wire, Manchester, biphase or other digital protocols, this tool is essential!

  • Speedy 24MHz

Logic samples each channel at up to 24M times per second. A large fraction of practical, real world applications run at less than 10MHz, and Logic is ideal for these.

  • 8 Channels

Logic has 8 inputs — it can monitor 8 different digital signals at once. For many modern microcontroller-based designs, this is plenty.

  • 10 billion samples

Logic can save as many as 10B samples, letting you capture even the most elusive events. No more dealing with frustratingly small sample buffers.

  • Comes complete

Start debugging within 5 minutes of opening your new Logic; everything is included: An ultra-flexible 22AWG 64/40 wire harness, 9 high-quality micro-hook probes, a USB cable (2 meter mini-B to A), and a nice carrying case. Download the software from our site (see software)

  • Enclosure

We love well made tools. That’s why we make Logic’s case out of custom CNC machined aluminum and make sure its anodized surface is finished to perfection.

  • Protection

Logic’s inputs are protected against overvoltage conditions via current-limiting resistors and ultra-low-capacitance diode clamps. A resettable fuse protects the USB ground return line to augment the USB host’s existing protection.

Saleae Logic – 8-Channel USB Logic Analyzer - [Link]

6 Jun 2011

This project is a remake of an old discolights pod. Original 24V 5W bulbs are changed to 230V 40W with E14 thread. Original driver board has non-typical signal input. This driver is based on the FT245RL chip, a USB-LPT converter – so you can use it with PC applications such as discolitez. Low voltage part is supplied directly from the USB so there is no need to to use any transformer…

Color Lights on USB – [Link]

6 Jun 2011

USB – RS232 converter, uses only Tx and Rx lines, with selectable 2400, 9600, or 38400bps. PCB projected to fit in old mobilephone cable, most of parts is surface-mounted. For more info see original autor Osamu Tamura site. Pcb’s, driver, and firmware is attached below.

Converter USB – RS232 – [Link]

6 Jun 2011

3in1 universal converter. Based on FTDI 232R chip seen as normal COM port, and two serial converters MAX232 and MAX485. Allow to be used as RS232, RS485, or UAR TTL converter. Connections parameters can be set through the system, as in normal COM port. Supported speeds: 110 to 921600bps.

3in1 converter – USB to RS232, RS485, UART - [Link]

6 Jun 2011

Arhi tested out the VEHO Discover VMS004 Delux USB microscope: [via]

As expected – the “tripod” is crappy but could be used with some modifications…

The unexpected “con” wrt this microscope is that it can only do 20x and 400x – nothing in between. Not really what I expected, but not too big of a problem at the end. The 400x is ok for examining joints only dof is so shallow that it will take some getting used to ..

VMS004 delux USB microscope - [Link]





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