Scasagrande shared his USB isolator project, that is available at Github:
I received inspiration for the project from other USB isolator projects on the internet. Mine features a few improvements to many of them:
USB-B and micro-USB connectors on the host (upstream) side
In addition to accepting power via the barrel connector (which goes through a basic 7805 low dropout linear regulator), there is also a micro-USB port for device-side power. This allows you to use the now common cell phone charger cube to power your isolated device
Push-button switch for easy USB disconnection events
Bypass jumper for linear regulator, allowing for 5V power from the barrel connector
Encased in a small box to protect the IC from the world
USB isolator project – [Link]
by Kalle Hyvönen:
I’ve been thinking about making a temperature logger for my room and my computer, I set on using DS18S20 sensors from Maxim because they’re common, cheap and overally pretty ideal. My computer is so new that it does not have a serial port (not 100% sure, I think there might be a pinheader on the motherboard with serial port connections) so I have to use USB for interfacing. Next thing I had to do was to make an USB to 1-wire adapter so I could attach the sensors to my computer.
I browsed around for a while and set on using the DS2490 USB-to-1-wire adapter chip because the circuit for it looked pretty simple. I modded the component values a bit from the ones on the original schematic from Maxim to ones I had in hand. I used 0805 sized SMD components because I have those in store.
USB-to-1-wire Adapter – [Link]
Are you encountering any issues with developing a full-speed USB application on NXP’s LPC microcontrollers? This application note from NXP highlights some of the important issues that you need to be aware of for a typical full-speed USB application. [via]
Implementing full-speed USB on NXP’s LPC microcontrollers – [Link]
cpldcpu did a teardown of an external USB battery:
The device has a USB micro-b socket which is used as 5V input for charging, and a normal USB-A socket as 5V output. The output power can be turned off and on by a toggle button. There are LEDs to indicate active power out (blue) and charging (red) states. The pictures above show the innards of the device. Most space is taken up by an ICR18650 LiIon battery, which are relatively common devices with 2600mAH. In addition, there is a tiny tiny PCB. The rear side of the PCB is dominated by a 4.7µH inductor, which is part of the boost converter to convert the 3.7V of the battery to the 5V USB output.
Tear down of a cheap external USB battery – [Link]
A purely software based USB peripheral for ARM Cortex M0+ devices. This software enables Cortex M0+ devices to act as Low speed USB device. It includes a lightweight USB & HID Stack and easily be optimized to consume only 4KB of flash.
LemcUSB: software USB for EFM32ZG (ARM Cortex M0+) – [Link]
TomKeddie shared his USB Isolator in dangerousprototypes’s project log forum:
This is a nice simple soldering project that does exactly that, isolates your USB port from connected devices. There are two input usb connectors, one carries data and power from the computer the other supplies power to the output. The output comes from a 3rd USB A connector. There is no power/ground/data connection between the computer and connected devices other than through the isolator chip. This board has two grounds, two power supplies etc.
Simple USB Isolator – [Link]
Frank Zhao shared his simple 6x USB charger with current monitor in the dangerousprototypes.com project log forum:
This is a simple 6 port USB device charger with a individual current monitor on each port. The charging current is indicated using RGB LEDs. Blue means slow charge (under 250mA), green means 250mA to 750mA, red means over 750mA, and purple means over 1500mA (for tablets). This circuit involves an ATmega328P (if you do hobby electronics, I bet you have plenty spares of these), INA169 (check out this breakout board), and a OKR-T10-W12.
Simple 6x USB charger with current monitor – [Link]
scasagrande shared his GPIBUSB Adapter rev3 in the dangerousprototypes’s project log forum:
This past weekend I finally finished up the third major revision of my GPIBUSB adapter board. Major hardware changes include swapping the pull-up resistors for the proper GPIB line drivers, as well as swapping the FT232RL for the newer FT230X. There is a number of software improvements from improved reliability to additional commands.
Open source hardware GPIB USB Adapter – [Link]
All-Dock: The fastest docking station in the world. Works with iPhone, iPad, Android, Apple, Samsung, Sony, HTC, Kindle, Nokia, Huawei
The All-Dock is the race car, the Porsche, of charging stations. It’s not just functional – charging multiple devices of nearly every type available – but also incredibly fast and spectacularly beautiful. When this project is completed, the All-Dock will surpass any other charging station in the worldwide market. You can be a part of this amazing effort by supporting us, and by doing so you’ll obtain a product you’ll be proud to display where everyone can see it.
Our dream with the All-Dock is to create more than just a charging station. The All-Dock is envisioned as a functional piece of art. It will offer a solution for the rapid recharging of multiple devices at the same time, compatible with nearly all devices, including Apple, Samsung, Blackberry, LG, HTC, Motorola, Huawei, Microsoft, Nokia, Kindle, Sony Ericsson, Nexus, etc. The All-Dock will enable you to work with, charge, dock and store your device – all with the same station. It will provide incredible value for money.
All-Dock: Universal USB charger for Tablet, Smartphone, etc. – [Link]
Ethan Zonca of Protofusion writes:
While developing the Luma RS485-networked LED driver we discovered a need for a small and inexpensive USB to RS485 adapter. We designed an adapter with a FTDI basic UART chip (FT230XS) and an inexpensive TI differential receiver (SN75176). Our small selection of parts brings the cost down to just over $5 for one adapter.
Open hardware USB to RS485 adapter – [Link]