Reblogging my own post from another site: I am traveling this memorial day weekend and I wrote a post on setting up your Raspberry Pi in a motel room to verify something quickly for a presentation etc.
I own a couple of multimeters and I am never able to find one when I need them. I relocate my residence constantly and hence end up leaving the multimeter in one of the random boxes and forget where I put it (next time, I plan to mark my boxes clearly) and I never unpack my boxes due to my laziness.
My brother shared this USD 8 multimeter deal on Newegg. I decided to get one as I find Radioshack multimeters to ridiculously overpriced. I consider the deal to be a steal and comes with a backlight (apologies for the low quality picture). The multimeter is available on sale from here.
Silicon Labs has announced an Internet of Things (IoT) contest recently. The contest revolves around building an application around the SIlicon Labs microcontroller. The winning project gets USD10K worth of components for building your own product
Interested in participating in the contest?
I was definitely interested though I was not sure if I had any chances of winning the contest. The first step is the purchase of the kit. The cheapest kit available was the EFM8 Universal Bee kit(shown in the picture below). It costs USD 30 and according to the documentation, this microcontroller is USB capable. I will let you know how my experiment goes..
I recently came across this contest from the makers of the PiFace Control and Display. The PiFace Control and Display is a stackable hardware board that comes with tactile switches, IR receiver for remote control applications and a small LCD.
I had less than a day to make something using the display. The theme of the contest is to countdown to a target date. I decided to use the Google coder image for the Raspberry Pi. The Google coder is a platform meant for beginners in web development and enables building our own website on a local network. A step-by-step instruction of the Google coder setup is available on the Google Coder page. The instructions are more or less similar to the Raspbian setup for the Raspberry Pi.
Accessing the Google coder platform from a Windows desktop requires the installation of the Bonjour drivers for Windows. The Google coder desktop can be accessed from a browser at the following address is http://coder.local. I downloaded the digital clock application from the Google Coder repository and modified the same to display the countdown timer on the PiFace Control and Display.
I modified the clock such that it is possible to pick a date to count down. I used pickadate.js to pick a date from the calendar. for the countdown selection. The clock pings a web.py framework based webpage with the countdown data which is consequently displayed on the LCD.
I also wrote a couple of lines to control the LPD8806 LED strip lighting using a TV remote control. Based on the number pressed on the TV remote, the python script reading the PICAD’s IR receiver, sends a control word to the Arduino controlling the LED strip to switch the LED sequence.
The Google Coder and the PiFace Control and Display setup instructions are available over the web. The modifications to the clock application and the python script are available from my github account.
I recently bought a Pi Lite board from Ciseco PLC, UK. The Pi Lite is an add-on hardware board for the Raspberry Pi. It comes with 126 LEDs and is controlled by an Atmega328p microcontroller (The one used in the Arduino Uno platform). The Pi-Lite uses the BCM chipset’s serial port for its communication to the Raspberry Pi.
Since the Pi Lite is a stackable add-on hardware, they have provided access to the Pi’s GPIO pins on the add-on board. It is possible to scroll messages on the Pi-Lite display by sending messages via the serial port on the Raspberry Pi. A simple step-by-step guide to setup the serial port to transmit messages to the Pi-Lite is available here.
I was able to run a simple program that fetches the currency exchange rate from the web and scroll the same on the Pi-Lite Display in two simple steps.
I got started by fetching currency exchange rate data:
import requests import json data = requests.get('http://rate-exchange.appspot.com/currency?from=USD&to=INR') jsondata = json.loads(data.content) retrieved_data = jsondata['rate'] print(retrieved_data)
We can scroll the retrieved data on the display by simply opening the serial port (The port at which the Pi-Lite is connected) and writing the string to it.
baud = 9600 port = '/dev/ttyAMA0' ser = serial.Serial(port,baud) ser.timeout = 0 ser.flushInput() ser.write(str(retrieved_data))
Combining the above two steps, we have:
import requests import json import serial from time import sleep baud = 9600 port = '/dev/ttyAMA0' ser = serial.Serial(port,baud) ser.timeout = 0 ser.flushInput() while True: data = requests.get('http://rate-exchange.appspot.com/currency?from=USD&to=INR') jsondata = json.loads(data.content) retrieved_data = jsondata['rate'] print(retrieved_data) ser.write(str(retrieved_data)) sleep(10)
I was not able to take a good picture due to the brightness of the LEDs. Hence, I am sharing a black and white video of the currency exchange rate being updated every 10 seconds:
Note: I am not promoting the Pi-Lite board!
MAKE magazine organized a web meetup today. Eben Upton (Founder of Raspberry Pi foundation), hackerspace folks participated in this meetup. If you missed it, here is Google Hangout video