Alexander Holler writes: [via]
This page describes how you can use a small AVR device and a real-time clock (RTC) to build a hot-pluggable USB real-time clock (I’ve named it just usb-rtc), mainly for usage with ultra-low-cost hardware meant to be used with Linux.
The overall cost for one of those thingies I’m describing here is about 15€-20€, which isn’t really cheap. But I find it a valuable thingy because the result is a hot pluggable RTC, usable by almost any device which has USB. So it’s very likely you will use it for much longer than the device you currently want to build or search it for. In addition you might want to use it as a (hot pluggable) USB-I2C adapter too. The software I’m describing below already supports that.
How to build an USB real-time clock - [Link]
Brian Schmalz writes:
The UBW board is a small board that contains a Microchip PIC USB-capable microcontroller, headers to bring out all of the PICs signal lines (to a breadboard for example), only costs about $15-$20 to build and is powered from the USB connection.
UBW – USB Bit Whacker- inexpensive, simple input/output USB device - [Link]
After the success of small modules USB – I / O converters – PUSBIO with MCP2200 circuit intended for development and small batch production, which we introduced in Article MCP2200 USB module and I / O , and recently introduced software for USB I / O modules , now the company introduces new modules Pandatron with relays and optocouplers.
USB Relay – I/O modules - [Link]
Small Arduino compatible USB host board. Take control of your Android phone or other USB device in your next project.
This project began the day I saw the Google IO 2011 talk about the new Android Accessory Development Kit (ADK). I had never seen or used an Arduino before. I had written a few Android programs but something about being able to connect custom hardware to my phone inspired me to start this long trip down hardware lane. Specifically, I was inspired to create motorcycle navigation software knowing that I would be able to create a remote control for my phone that would allow me to control the software with gloved hands. I finished the navigation software a few months later, and it has been a great success. This board has allowed me to complete that project; I now have a remote control attached to my motorcycle.
Mini USB Host Microcontroller Board – Arduino Compatible - [Link]
The micro-sized, Arduino enabled, usb development board – cheap enough to leave in any project! Erik Kettenburg writes:
The Story: We set out to build a little brother to the wonderful Arduino line of development boards – we were tired of leaving our valuable Arduino’s behind in projects, or worse, ripping apart old projects to build new ones! We also felt the Arduino was too big and powerful for many projects where we only needed a few pins, or an SPI or I2C bus. And so the Digispark was born! To us, the best things about the Arduino is the community, the easy of use, and the IDE – by making the Digispark an Arduino compatible development board all of those remain common. Plug it in, power your project with USB or external sources, program it with the Arduino IDE, and easily use existing Arduino code! But with its small size and low cost you can feel free to leave it in your project, give one to a friend, and use them everywhere!
Digispark – The tiny, Arduino enabled, usb dev board! - [Link]
FT245RL IC testing software. You can set the output and get input status from your PC’s screen. It is thus possible to enable or disable the 8 channels, for a 8-channel input.
FT245RL Test Software - [Link]
This is just a friendly FYI to all hackers. Once you get a little more adventurous you can get real confused about what usb devices are plugged in etc (which com ports,…)
my best new friend is usbdeview from nirsoft http://www.nirsoft.net/utils/usb_devices_view.html
It shows you everything about the plugged in usb devices, updates on the fly, v good
USBDeview: Debugging USB devices - [Link]
The AVR Stick is a simple data logging device that instantiates itself as an HID keyboard and reports the voltages, along with a ‘timestamp,’ from two pins on an ATtiny85. The device uses open source firmware availabe from Objective Development (http://www.obdev.at/vusb/) called V-USB to implement the USB 1.1 standard. The code that runs the application was based on the EasyLogger example application from Objective development.
AVR Stick – A simple USB data logging device - [Link]
Jürgen Beisert writes:
I like the handy DCF77 signal. In this project no clock should use it, instead the computers in my home network should be served by a precise time reference. Due to the fact most other interfaces are no longer available on modern computers, it uses the USB to forward the prepared DCF77 signal to the host.
DCF77 to USB converter - [Link]