Experiments, Bygones, Perspectives
Your computer (
What it has is an Ethernet port and therefore, the
I am using Ubuntu on the
nm-connection-editor
Shared to other computerswifishare as the Connection name at the top
now, I connected the
send messages between the HM 11 BLE modules and my Raspberry PI 3 with its onboard BLE.
Bluez comes installed with the raspbian distro.
Wiring is basic UART for connecting the HM 11 to the Arduino. In my case, I am using a Teensy 3.6 programmed using the Arduino IDE.
Use this serial proxy sketch for getting started. if you have Arduino IDE, open this file. Teensy serial ports are on 0 and 1. I kept it software serial so its easy to adapt for any other board by just changing the pins used for the UART.
Thats all you need to setup on the Arduino side. Everything should work now.
May be try a few AT commands. AT should give you OK if the module is used for the first time. if not OK+LOST which means that the module was connected previously which was lost. I would, either way, try the three AT commands just to be on the safer side. AT+RENEW, AT+RESET, AT.
Next step is to set up the raspberry pi, everything should be available directly up setting up an RPi with a new SD card. Be sure that you are using Raspberry Pi 3 and newer versions which have onboard BLE.
Below is my notes. If I recall either Android or the RPI didn't like the 6 digit PIN
— Greg Bray (@GBrayUT) February 21, 2019
//Setup HM-10 BLE module (See datasheet-HM-10-BLE.pdf)
//Use serial to send OK (no line ending)
//AT+PASS? to view pin (currently 001122)
//AT+TYPE? 2= bond with pin, use AT+TYPE0 to disable
you should know the HM 11 Mac address. you should know it if you did it through
Install system dependencies, Go into the directory, Install the python dependencies. Before starting the python program, change the address that you want to connect. After you did that, start the program, it should send Hello world once to the device and wait for any messages. If you enter in the serial monitor, it will be printed out by the python program.
# sudo apt-get install build-essential python-pip3 git
# git clone https://github.com/akrv/BLEserialbridge
# cd BLEserialbridge
# pip3 install -r requirements.txt
# python3 serial_bridge.py
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.
In addition, since we know that the curve should fit a quadratic function of the form
fe(T) = −A · (T − T0)2 + B,
where A is the temperature coefficient, T0 = 20◦C represents room temperature, and B is a frequency error offset, we can fit the measured calibration points to this curve and obtain frequency error estimates for previously unobserved temperatures, thus drastically improving the range and accuracy while eliminating a factory calibration step and allowing on-demand calibration. [5]
During active periods, the high-frequency clock is turned on, and a hardware counter counts the number of high-frequency clock ticks that occur during each low-frequency clock interval, i.e., there are high-frequency clock ticks during each low-frequency one.
φ0 = fL / fH
At the time of the event, the system records not only the value of the counter sourced by the low-frequency clock but also the value of the counter sourced by the high-frequency clock which was reset at the end of the most recent clock tick of the low-frequency clock. Thus, this second timer will indicate the phase φ within a low-frequency clock tick, allowing an effective resolution to be up-sampled to the high-frequency clock (modulo one cycle of jitter). The event time is sampled as
tevent=CL ·φ0 +φ.
The requirement is quite simple and the target chipset used in this project has additional two timers.
The Capture mode which will retrieve a timer value based on a signal event.
The Compare mode which will constantly monitor a timer counter value and compare it to a value set in the application. When they match, it will trigger an event.
The target implementation is on CC1350 chipset [6]. They have Four General-Purpose Timer Modules (Eight 16-Bit or Four 32-Bit Timers). With newest hardware revision CC1352r, almost same chip can be used to run Bluetooth 5.0. This has a M4 instead of a ARM M3 processor. This optimization with the increase in the memory footprint can be attributed to the new Bluetooth 5.0 standard.
The application framework used will be Contiki-OS [7]. I will use the latest version that is on development which also supports the SensorTag board and the launchpad [8]. A toolchain setup and compilation of the Contiki-OS is done in this post.
The two capture are connected to the event. The paper expects to make the interrupt for start of the frame delimited (SFD) which is previously justified for better resolution on clock synchronisation in figure 2 [5].
An additional capture unit on the fast timer captures the counter on every low frequency rising edge. As the Sync event, where the value of h0 is stored in one of the capture units. Later, when the SFD line rises, the two capture units on the two timers store l0 (the value of the low-frequency counter) and wh1 (the value of the high frequency counter), respectively. Using these three captured values, the event time can be calculated as
tevent=l0·φ0+(h1−h0) modφ0.
Counter overflows are an issue to be tackled. Overflows of the high-frequency counter are not a problem since they run only on a short burst when the system is synchronising / listening for packet. The low-frequency clock must have a counter width of 64-bit since 32-bit counters will overflow by 5 minutes since the low-frequency counters are used for long intervals.
As per the suggestion on [5] a 32KHz and 8MHz clocks are used for the timers. The MCU has Clock Speed up to 48-MHz.
[1] http://www.isis.vanderbilt.edu/sites/default/files/Maroti_M_11_3_2004_The_Floodi.pdf
[2] https://www.tik.ee.ethz.ch/file/5562ed988ca095af8331114dd81c6c70/sensys09_slides.pdf
[3] https://people.mpi-inf.mpg.de/~clenzen/pubs/LSW09optimal.pdf
[4] https://ieeexplore.ieee.org/document/5170185/
[5] https://web.eecs.umich.edu/~prabal/pubs/papers/schmid10vht.pdf
[6] http://www.ti.com/lit/ds/symlink/cc1350.pdf
[7] http://contiki-ng.org/
[8] https://github.com/contiki-ng/contiki-ng/wiki/Platform-srf06-cc26xx
Some bookmarks to read if you are a distributed systems researcher [1]
when you start the debate (here central systems are included): [2]
References:
Install the following packages. you might need sudo right.
# sudo apt-get remove gcc-arm-none-eabi gdb-arm-none-eabi binutils-arm-none-eabi # sudo add-apt-repository http://ppa:team-gcc-arm-embedded/ppa # sudo apt-get update
Native means that your code will compile and run directly on your host PC.
for me, it will run on the Ubuntu 16.04 OS on the VM.
cd into your development folder.
# git clone https://github.com/contiki-os/contiki # cd contiki/examples/hello-world # make TARGET=native
mkdir obj_native CC ../../core/ctk/ctk-conio.c CC ../../platform/native/./contiki-main.c CC ../../platform/native/./clock.c CC ../../core/dev/leds.c ### output truncated ### AR contiki-native.a CC hello-world.c LD hello-world.native rm hello-world.co
The target command tells the compiler to compile for the current system.
This is what is later changed for cross compiling to our target platform.
Type the following command to run the hello-world program.
# ./hello-world.native Contiki-3.x-3343-gbc2e445 started with IPV6, RPL Rime started with address 1.2.3.4.5.6.7.8 MAC nullmac RDC nullrdc NETWORK sicslowpan Tentative link-local IPv6 address fe80:0000:0000:0000:0302:0304:0506:0708 Hello, world
if this is how it worked! your compilation worked!
The only thing to be changed is the target. make clean is an important step.
make clean make TARGET=srf06-cc26xx BOARD=sensortag/cc1350
this says the compilation works if you see the following:
CC ../../cpu/cc26xx-cc13xx/lib/cc13xxware/startup_files/ccfg.c CC ../../cpu/cc26xx-cc13xx/./ieee-addr.c AR contiki-srf06-cc26xx.a CC ../../cpu/cc26xx-cc13xx/./fault-handlers.c CC ../../cpu/cc26xx-cc13xx/lib/cc13xxware/startup_files/startup_gcc.c CC hello-world.c LD hello-world.elf arm-none-eabi-objcopy -O ihex hello-world.elf hello-world.i16hex srec_cat hello-world.i16hex -intel -o hello-world.hex -intel arm-none-eabi-objcopy -O binary --gap-fill 0xff hello-world.elf hello-world.bin cp hello-world.elf hello-world.srf06-cc26xx rm hello-world.i16hex hello-world.co obj_srf06-cc26xx/fault-handlers.o obj_srf06-cc26xx/startup_gcc.o
This error absolutely means that the installation of the compiler for cross-compilation wasn’t successful.
/bin/sh: 1: arm-none-eabi-gcc: not found
Next step would be to compile with contiki-ng since, there is active development is happening there and to base all developments to that repo.
# git clone https://github.com/contiki-ng/contiki-ng # cd contiki-ng # git submodule update --init --recursive
navigate to the hello-world example and hit the following
# make clean make TARGET=srf06-cc26xx BOARD=sensortag/cc1350
[1] https://sunmaysky.blogspot.com/2015/08/setup-6lbr-to-run-6lowpan-with-cc2531.html
[2]https://sunmaysky.blogspot.com/2015/09/contiki-subg-hz-6lowpan-on-cc1350.html
When there is a city wide Wireless Sensor Network (WSN), this has to be resolved with anything meaningful, say name of where it is located. then this has to be the name that it should be resolved to.
to creat DNSed, as in past tense in English for DNS. To DNS the shit out of the IoT. To create an amazing network and to overload the DNS servers. To create everything out in the open, so everything in the Hollywood movies can come true.
then, this can be described in the internet nomenclature as
this would translate to an internet name of “level.256.water.meereen.got”
usually, there is only a sensor in a an area and they are organised in cluster.
in that case, Meereen’s water tank is being referenced, and the sensor 256 is being addressed where the level is being asked for, https://256.water.meereen.got/level where level is a service provided by the sensor
It is possible to use BIND9 to build a DNS server, then create the zone records to point to the different sensors. the tutorial gives a good insight on deploying a BIND9 DNS server [3]. There are very good python libraries available in such an instance to build an DNS server and then work with their API. The following are some interesting DNS APIs for python to process DNS records on server.
[1] http://www.dnspython.org
[2] https://pypi.python.org/pypi/easyzone/1.2.1
In this effort, the implementation takes advantage of the REST API provided by DigitalOcean to make the DNS. as the idea is to create a very dynamic name resolution for IoT devices and this does not involve building a DNS server from scratch. The DNSed will be a library that will used in the IoT devices as well to communicate to the central server which will be further proxied to the DNS Server of DigitalOcean. This architecture would provide a method to have a better security by not distributing the API keys throughout the network on every device.
The functional block diagram below tries to describes this exact architecture
[1] http://www.dnspython.org
[2] https://pypi.python.org/pypi/easyzone/1.2.1
[3] https://www.digitalocean.com/community/tutorials/how-to-configure-bind-as-a-private-network-dns-server-on-ubuntu-14-04
[4] https://developers.digitalocean.com/documentation/v2/#domain-records
[5]
Why Do Research?
References:
The above video is from a research lab at the MIT Media Lab called Responsive Environments. They have a really interesting article [1] about a multimodal mediated work environment.
Internet of Things has been of great buzz these days. It is interesting, but why is it interesting? Just made a project/home lighting on this project.
So, here is the scenario for the internet of things. The thing in the Internet of Things is the web controlled lights – LED strip. The “control” part of the lights is managed by the Arduino. The task of Arduino would be to “GET” data that matters and send that info to the light strip. The ways in which the LED strip can be manipulated from the Arduino can be listed as
Which makes a lot of math and logical decisions for the Arduino to handle. That is the whole point of networking these devices, now they have access to on-demand computing resources. This means we need the medium to connect the Arduino to the internet. That is done using the WiFi module which communicates with the Arduino using USART communication.
There are two ways to handle the information flow:
Tools used:
Low cost, easy implementation of mediated atmospheres, to make your apartment to provide sensible lighting that can help harmonize the body and mind with the circadian rhythm.
[1] 17161.JosephA.Paradiso.Preprint1.pdf
[2] 192196471
That moment! few hours before the new years!
A probable feel of dashing adrenaline because of
It could not have been better!
Its just gonna get better!
An amazing page in the book of time where a year is a a sheet smeared with melancholic emotions, careless decisions, withering memories, inspirational failures and motivational achievements.
Incredible year with the force awakening in the end!
There is a stir to settle down! got stirred, probably will settle down… looking ahead for the future.
Its all about the vibes and the motions!
Listed for the good times I have had being there!
