Saving as Draft. Text coming soon
Caution: This by no means is a step-by-step or exhaustive guide on installing SSL Certs on your website. This will simply share some notes I made yesterday while migrating my site over to HTTPS. Exercise extreme caution. I’m not responsible (in any way whatsover) for any loss or fall in rankings or loss of revenue or downtime due to application of notes. I caution because I’m not a Web expert and I don’t understand the ramifications of experimenting with this. Hence, this post is only for Educational purposes 🙂
I spent almost the whole of my new year 2017 Day 1 migrating over from http://potentiallabs.com to https://potentiallabs.com and likewise moving our main eCommerce Store (running off OpenCart) over to https://potentiallabs.com/cart
This post will walk you through the 3 methods of SSHing into the C.H.I.P without using any external Display Screen. This is helpful if you don’t have the HDMI/VGA add on modules for the CHIP or don’t have an old TV that takes in those oldie RCA composite video signals.
After waiting for more than 6 months, the C.H.I.P finally found a place next to a Banana in my home:
The first thing todo when you get something is to power it on and see the funky lights that come up to make sure it’s not DoA (Dead on Arrival). And then, take a pic and Tweet it out to show off to the world 😛
— Syed Anwaarullah (@Anwaarullah) November 23, 2016
Once done, now figure out how to get started with it.
It’s easier if we have the HDMI/VGA add-on module for the CHIP that’ll allow us to simply hook up the CHIP to a display unit and get started with a K/B & Mouse. I didn’t buy one, so I’m now worrying how do I get started with. Turns out, the CHIP and the PC can be directly connected to each other through a simple Micro USB Cable and tinkered with.
An extract from http://docs.getchip.com/chip.html#headless-chip that outlines these three methods:
One of the most amazing features of CHIP is that it’s insanely simple to use it as small, wireless computer. Low power requirements, battery-powered with charge management, and both WiFi and Bluetooth connectivity makes CHIP easy to run as a headless, autonomous machine. Of course, you’ll still want to access it and control it without a monitor or keyboard. You can control CHIP with another computer and a serial or network connection. Here’s how you do this.
If you want to use CHIP without a monitor or keyboard attached, there’s a few ways to do this:
- Serial connection between a computer and CHIP with a micro-USB cable (USB OTG)
- Serial connection between a computer and CHIP with USB to UART cable
- Secure Shell (SSH) over wireless or wired ethernet
OK, all the info for getting started with any of the 3 methods is there in the link above. Why do we even need this post?
Except… Method 1 won’t work on my PC!
C.H.I.P doesn’t show up as a recognized COM Port on my Windows 10 PC 🙂
So Method 1 from the official docs won’t work for us (at least for now). Let’s move onto the 2nd Method
Use a USB-Serial Console/Debug cable, hook it up and SSH.
Now, we can simply open up Putty and enter our COM Port of the USB-Serial Cable to login into the C.H.I.Ps console:
Now, while you’re inside, you can go and setup the CHIP to connect to your WiFi network so that you can SSH into it.
Edit the interfaces file and add creds for the local WiFi:
You can now reboot, wait for a min and SSH into the CHIP directly through it’s IP or hostname:
All good! End of Story!
Nope, Method 1 (USB – PC) didn’t work, so let’s make it work!
I found an excellent tip by lordhex on the community forums here: https://bbs.nextthing.co/t/putty-connection-step-by-step-for-windows/1636/11 and I did just that to get this method working.
I made the CHIP install itself against this driver, and boy, it finally showed up as a COM port!
Make sure you have disabled the Driver Install from Unknown Sources restriction on Windows 10 (to do this, hit Shift and restart PC, and you’ll find that option there).
I’ve uploaded the Driver File that I used and you can simply download and use when the CHIP shows up as a Composite device instead of showing up as a COM port.
Download from here: https://www.dropbox.com/sh/ng9acv78t0wn6mo/AACAFKRu4LNqvN5XRuFMj7Noa
The FX570ES is functionally identical to the FX991ES except that the 570ES has a AAA battery whereas the 991ES has button cells.
I owned both of these during my engineering days and is arguably now the only proof that I actually did my Engineering 😛
Here’s the teardown:
The missing controller blob!
^ Missing the controller blob!
I really can’t do a detailed tech analysis as the main controller blob is misssing. So apart from the obvious buttons and LCD and Battery, there ain’t anything to look into
I did this teardown on my broken Calci, notice the cracked screen 😛
More teardowns coming soon.
If you followed my earlier tip, notice how I always passed in Image.png as an image file into tesseract to get a text value? This is totally fine if you can source static Image files and make sure they are available at a particular location.
However, what if you’re using a live camera that saves a stream of Images? I used mjpg-streamer to live stream images on a web browser and also save them on a Raspberry Pi.
Following is the bash command that captures images from a USB WebCam and streams it over:
./mjpg_streamer -i "./input_uvc.so -r 640x480 -f 1" -o "./output_http.so -w /usr/local/www" -o "./output_file.so -f /home/pi/Camera_Output -c /usr/bin/mjpg-streamer-overwrite.sh"
The above command does the following 3 things:
- Stream Images over the Web/Browser
- Save Images to a local folder on the Raspberry Pi
- Invoke a custom Script
Here’s how the local folder containing the saved streamed image files looks like:
Now here’s the challenge: Firstly, tesseract can only take in a defined fileName as an argument and since we’re invoking tesseract from Python, we can’t simply use a script to get the latest file name and pass it as a parameter.
So here’s what I did to solve this: Get the latest file and rename it to Image.png in that same folder. So at any instance, the latest captured image file is always Image.png. Now, simply pass this as an argument into tesseract and all’s done 🙂
I used the following code snippet to get latest file pointed as Image.png:
# move the temporary file to a given filename cd /home/pi/syed cp -f -T `find -type f -name '2015*' -printf "%C@\t%P\n" |sort -r -k1,1 |head -1 |cut -f 2-` /home/pi/syed/Image.png
I saved this snippet into mjpg-streamer-overwrite.sh which is being invoked on every Image capture as shown earlier.
P.S: A more detailed script that shows debug messages:
#!/bin/bash # comment out the following line to disable messages #VERBOSE=1 if [ $VERBOSE ]; then echo -e "Rename script started at:\t$(date)"; echo -e "Parameter \$1 is:\t\t$1" echo -e "current directory is:\t\t$(pwd)" echo -e "move command is:\t\tmv -T -f \"$1\" 'Image.jpg'" fi # move the temporary file to a given filename cd /home/pi/syed cp -f -T `find -type f -name '2015*' -printf "%C@\t%P\n" |sort -r -k1,1 |head -1 |cut -f 2-` /home/pi/syed/Image.png RES=$? if [ $VERBOSE ]; then echo -e "move command returned:\t\t$RES" fi
While building an ALPR (Automatic License Plate Recognition) System on a Raspberry Pi in 2013, I came across tesseract which is a very powerful OCR (Optical Character Recognition) tool.
Tesseract is a command line tool which means it has to be invoked as a command from the shell/terminal (and it works on both Windows and *nix):
tesseract imagename outputbase [-l lang] [-psm pagesegmode] [configfiles...]
Since my main image capture and trim script was based on Python (triggered from a WebPage), I had to find a way to invoke tesseract from within Python. At first, I looked out for python libraries and wrappers of tesseract and had a hard time getting them to run on the Raspberry Pi.
Eventually, I wondered if there was a way to invoke shell commands from Python; and yeah!
Using subprocess, you can do just that:
import subprocess subprocess.call(["tesseract", "/home/pi/syed/Image.png", "/home/pi/OpenCV/OCR_Data"])
Pass each argument to the invoked command separated with , in “”
One of my acquaintances pinged me today asking for suggestions/ideas for his Engineering project themed around IoT. At first, I gave my standard reply:
And at that instance, it hit me to get ideas from use-cases provided by leading IoT Companies such as the Kaa Project (http://www.kaaproject.org/) and many others.
I’ve compiled below a list of IoT Project Ideas for your Engineering Projects or IoT use-case demos and have listed them below with links back to the source. You can use these as a starting point and generate your own use cases or directly implement one of these. I’ll try adding in more use cases from other vendors. Happy Making (instead of ready-made buying :P). Ohh, it’s Engineer’s Day today. Happy that.
The following use-case examples were taken from: http://www.kaaproject.org/iot-use-cases/
We often come across projects where we’d like to quickly hook up a sensor or an actuator that works on 5V to an Arduino (Uno and others) without using a breadboard. Since the Uno has only one 5V Pin, an easy way to get additional pairs of VCC+GND is to use the ICSP headers available for the Atmega328 and Atmega16U2.
One cool thing/feature I learned from the Arduino Uno WiFi board was how to implement/add an extra hardware Serial Port to the existing MCU using a I2C to Serial Bridge.
The Atmega328P MCU on the Arduino Uno has only one Hardware Serial port. If we’re interfacing a Serial Device to this MCU and would also like to use Serial debugging, an option is to use SoftwareSerial (which comes with it’s own set of issues and limitations). A better option is to have an I2C – Serial Bridge that’d allow the host MCU to interface with another Serial Device.
The Arduino.org team did this splendidly and used this SC16IS750IBS to have the MCU talk with the on-board ESP8266 through this I2C to Serial Bridge.
You can read more about the implementation and details on the product page: http://www.arduino.org/products/boards/arduino-uno-wifi
If you natively develop firmware on the ESP8266, you’d eventually have to flash multiple bin files to different locations on the Flash Module of ESP8266 (or on SoC itself for ESP8285).
In order to create a single bin file, populate the individual bin files at their respective addresses in the official Espressif Flash tool as shown below:
Once done, select the checkboxes of the individual files that you’d like to include and hit the Combine Bin button shown above:
That should give you a single bin file as shown below:
Now, you can simply use the Flash Tool itself or esptool.py/exe to flash this single bin file at address 0x00000.
I found a simple batch file online that uses esptool.exe (for Mac/Linux, you can use esptool.py with the proper arguments) to flash bins to the ESP.
The following code goes into the batch file that calls the esptool.exe and flashes the bin file (mare sure esptool.exe and the bin file are in the same folder).
@echo off set /p comport= Comport (example 3, 4, ..) : echo Using com port: %comport% esptool.exe -vv -cd nodemcu -cb 115200 -cp COM%comport% -ca 0x00000 -cf at.bin pause
The above script will simply ask the user for the COM port of the USB-Serial Cable/Adapter to which an ESP (in boot-mode) is connected and flash it.
The above method can be also be used if you’re provisioning users themselves to flash/update firmware over to the ESP if FOTA is not implemented (at least that’s how I plan to use it for my ESP dev board).