Category: General

Yup, just like always open the terminal and put in the following to find the dev path of the SD card. diskutil list NO NAME with ID disk5 is what we will have to unmount diskutil unmountDisk /dev/disk5 Now, copy the data to the SD card using the dd command on the terminal after to cd into the folder where you have downloaded the image. Usually its in the downloads folder when you do it with safari. sudo dd bs=1m if=2015-05-05-raspbian-wheezy.img of=/dev/rdisk5 After sometime the terminal cursor blinks, it will look like the following image when it is successful. I didn’t come across the error from the actual source page, but when it does, look it up here -> Official Documentation (which is also my source)   as the title says, lets hit the raspberryPi with the new card and kick on with some electrons!

Pointers for distributed vs decentralised: Some bookmarks to read if you are a distributed systems researcher [1] A decentralized system is a subset of a distributed system. The primary difference is how/where the “decision” is made and how the information is shared throughout the control nodes in the system. Decentralized means that there is no single point where the decision is made. Every node makes a decision for it’s own behaviour and the resulting system behaviour is the aggregate response. A key characteristic of decentral systems is that typically no single node will have complete system information. “Distributed means that the processing is shared across multiple nodes, but the decisions may still be centralized and use complete system knowledge” says coinbase in their blog post A scenario to think of: Some control algorithms I’ve seen for multiple quad-copter control are purely distributed in that a central over-seer gives optimization problems to each copter to solve then return the solution. The over-seer will then issue commands based on the aggregate result. Here’s a philosophical question: if the over-seer is “voted” into office by the nodes, is it decentralized or centralized? I’d have to say decentralized, but it is arguable says MaRi Eagar then I tend to ask what is distributed systems? Keywords that matter when you start the debate (here central systems are included): [2] Points of Failure / Maintenance Fault Tolerance / Stability Scalability / Max Population Ease of development / Creation Evolution / Diversity References: What is the difference between decentralized and distributed systems?… Read more

Straightforward, three lines on the command-line to hit the git remote of bitbucket! git remote rm origin #Removes old origin git remote add origin https://[email protected]/your.new.repo #Adds new origin pointing to BitBucket git push -u origin #Pushes commits to new repo

This is not going to take too long for you to test your first Contiki program which will enable you to test your environment setup and also to understand the procedure of development using Contiki-os for the target chips CC2530 and CC2531. The port is done only for CC2530 and then it is extended to CC2531 so you just have to add another line to your build file so it compiles for the right target. Almost all the features of the chip are available using contiki. The following link for the feature matrix is from the official wiki [17.10.2014] List of Hardware Features Texas Instruments cc2530 DK Sensinode cc2530EMs on SmartRF05EB cc2531 USB Dongle N740 NanoSensor N601 USB NanoRouter SoC cc2530F256 cc2531F256 RC230x (cc243xF128) SoC Features MCU Enhanced Intel 8051 core, using the standard 8051 instruction set. RAM 8 KB with data retention in all power modes 8 KB (4 KB data retention in all power modes) Flash 256 KB 128 KB RF 2.4 GHz IEEE 802.15.4 compliant RF transceiver 2.4 GHz IEEE 802.15.4 compliant RF transceiver, based on the cc2420 radio core Sensors VDD, On-Chip Temperature Other cc2431 Location Engine1 Hardware AES Encryption/Decryption (AES Co-Processor)4 Hardware Random Number Generator Peripherals LEDs 42 2 2 2 Buttons 12, 3 2 2 0 I/O Connectors RS232 (UART0) USB MiniUSB (to UART1 over FTDI or to program) USB (to UART1 over FTDI or to program) USB (to program) Debug Connector 9-pin (to program) Debug Connector Serial Flash 256 KB OnBoard SPI Flash4 Numonyx… Read more

  I believe you have already ready the previous post about setting up the environment. if not do it here! <PSYCHOPY APP DEVELOPMENT IN PYTHON USING ECLIPSE AND PYDEV> So, now you are for sure ready with the environment and already created your first application on python. But psychoPy? yes, its not a big deal, you are 80% complete from creating an application in psychoPy already. These following steps hit the rest 20%. Set up the interpreter to be psychoPy. This enables you to use psychoPY API.

[toc] Confidence is pretence, courage is a combination of thought and action – #akrv Introduction Most of the reading notes are based on psychologist who try to prove confidence as a myth and making it something more comprehensible. Definitions: Self-confidence is a positive and balanced attitude having to do with the Self dimension. It consists of a basic belief that we can do what is needed to produce the desired outcome. Emily A. Sterrett, Ph.D. [8] the paradox of confidence as said by a British philosopher and a Nobel laureate One of the painful things about our time is that those who feel certainty are stupid, and those with any imagination and understanding are filled with doubt and indecision Bertrand Russell Motive Confidence is a mind-set which comes from within, and it’s attainable for all of us. With that in mind, choose to be confident Susie Timlin Global Director of People & Culture, Hays Talent Solutions   Leitmotif to get off the muddle Concepts that have always proved to be helpful. There is always a guide book, there is always 5 7 steps to grievance confidence. Here are some nice means that were posted in many scientific articles and other important icon that can just be considered enlightenment. changing posture [1], there was also an article about reverse stimulation, where you could smile when you are sad making your body to feel the happiness and there by creating a small window to escape depression. smiling before you are angry could release the steam off…. Read more

[toc] Introduction Got a few ITEAD Sonoff WiFi switches to automate my home. Why use the boring software, so I tried to hack the switches. This is a reference manual for me, but quite useful for anyone else if they want to use micropython, mqtt, web server and control the switches. Required items Sonoff switch VCP: FTDI Cable yeah, 5x pin headers to solder on the board few jumper wires for debugging Flashing micropython Make sure the FTDI cable is set to 3V which is very important. Then connect the cable as detailed in the table. Programmer Sonoff (counting from the switch to bottom) 3V3 1 TX 2 (RX) RX 3 (TX) GND 4 5 The easiest way to flash the firmware is to use the nodemcu-flasher available. Unfortunately available only for windows. The micropython-flash image esp8266-20170108-v1.8.7.bin can be downloaded from the website. On the config tab add the image. Sometimes it helps to first flash a blank image to the WiFi switch.  INTERNAL://BLANK   Installing MQTT Install mosquitto, an open source MQTT broker. It is very easy to install, follow the installation instructions in the link or copy paste the following commands.   This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode characters Show hidden characters wget http://repo.mosquitto.org/debian/mosquitto-repo.gpg.key sudo apt-key add mosquitto-repo.gpg.key cd /etc/apt/sources.list.d/ sudo wget http://repo.mosquitto.org/debian/mosquitto-wheezy.list sudo wget http://repo.mosquitto.org/debian/mosquitto-jessie.list sudo apt-get update sudo apt-get install mosquitto view raw… Read more

First, it was conceived to overcome an web exploit, called Cross site request forgery. This is well explained in the answers from the stack overflow question [1]. It is well explained well with a banking page. It will be very evident in a hacker situation. Cross site request forgery can be simply overcome by token based authentication of the user requests by cross checking every request with a token. A token is a random number generated by the server and served with every page that is served. On an Internet-of-Things context, it is very important when there are a lot of devices, a lot could happen even within your devices without any attacks. OAuth is a method of authenticating using a time based token. The token verification is time based, the verification will not pass through when the token time is finished. Looks like JWT, Json Web Tokens, is an evolved format of oauth where every communication is working on json based messages. A lot of negotiations are going on. It is very amazing to look at the evolution of these technologies. Incase of IoT it is important to keep it simple without compromising on the level security. References: [1] http://stackoverflow.com/questions/5207160/what-is-a-csrf-token-what-is-its-importance-and-how-does-it-work [2] https://en.wikipedia.org/wiki/OAuth [3] https://en.wikipedia.org/wiki/JSON_Web_Token [4] https://jwt.io  

Motive in systems communications, timing is very important just like when two people talk! time synchronisation is the key when it comes to nodes in a network how do we perceive/sense time naturally? — Aswin (@akrv1) July 21, 2018 Starting with that, Guide to implementing a Clock synchronisation algorithm on low power wireless sensor networks. following will be some pointers and papers to read before wandering in the wild to get things done and reinventing the wheel. Literature survey Message Time-stamping in Sensor Networks Flooding time synchronisation protocol [1] this protocol is very good in terms of single of time synchronisation it uses linear regression, get ready to do some compute on your MCU very good numbers and explanation in those slides [2] for multi-hop networks, this one is a good paper to read Optimal Clock Synchronization in Networks [3] Send fast synchronization pulses through the network to sync clock in networks pulseSync is the algorithm Temperature Compensated Time Sync [4] The only requirement on that time synchronization protocol is that it can calculate the current frequency error with respect to the reference node’s clock. Unlike other time synchronization protocols, TCTS also records the current temperature during a synchronization exchange. Both the temperature and frequency error at the end of the synchronization exchange is cached in a frequency vs. temperature table in memory. [5] Before attempting subsequent resynchronization, TCTS will measure the current temperature and consults its internal calibration table. If the current frequency error for the measured temperature is cached, TCTS… Read more

Sorta, will kill your phone! When the date of a 64-bit iOS device is set to January 1, 1970, the device will fail to boot. Connecting the device to iTunes and restoring the device to factory defaults will not put the device back in working order. Instead, a physical repair is required. but it is interesting to breakdown from what we already know! It is reported only for 64-bit iOS devices – I don’t know yet if that also means 32-bit? but I looked what it encompasses.. Excluding those devices with 32-bit processor iPod touch 5th Generation and before iPad 3rd Generation and before iPhone 5C and before From assembling PCs I know for a fact that if you replace that small coin battery, it will reset your clock. I m not if that main battery is also that battery. In that, remove your battery and put it back would be one solution that comes right out of my mind. But it seems like there are special tools involved its better to goto the Apple Store to get it fixed, is the only solution for now. DON’T DO IT! would be the advice. There are few baits around and I hope if you google before you do it, this comes up and you are safe. Baits I have seen on the internet: This goes around on twitter, https://twitter.com/gabdi_/status/698230041591836672     Security issues: NTP! simple, just change the time on the server, boom, all of the iPhone 6 will go off. Best skynet hack for dropping… Read more