Year: 2014

Host Multiple Webservers Out Of One IP Address (reverse proxy) Using Ngnix

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It’s easy enough to host a single website out of a residential internet connection. All you have to do is open up port 80 on your router and bind it to the local IP address of your server as follows:

But say you’re like me and have multiple domains and therefor want want to host content for mutliple domains on the same IP address like this:

Say you want to further complicate things further and have unique physical computers for hosting each site. The quickest and easiest way to do this (so I’ve found) is using a Ngnix Reverse Proxy.

The topology for accomplishing this looks a lot like this:

The ONLY things we need to deal with in this diagram is the Ngnix Server and the router. For my setup it is a virtual machine running Ubuntu 10.04 x64. Setting up the software is pretty simple as well. First we need to install Ngnix:

After that we need to add the configuration files for each server. The procedure for doing that is as follows. You need to do this for EACH server you add to the reverse proxy.

For this example I’ll be using example.com as the domain and xxx.xxx.x.xxx as the IP address on the local network of the machine I’d like to host example.com on.

Create the config with:

The create then fill it in:

Note the line

This limits the file size that can be transferred through the reverse proxy to the target server. If you are transferring larger files, you will need to increase this value, but 64M is more than enough for most applications.

From there, you need to “activate” the new redirect by symbolically linking it with a config in the enabled sites directory in Ngnix with:

Restart ngnix and we’re done!

Now to configure the router.
It’s pretty easy, all you need to do is forward port 80 on the router to the local IP address of the Ngnix server. On my router that looks like this

Where 192.168.1.217 is xxx.xxx.x.xxx in my example.

Thanks for reading and if you have any questions leave them in the comments.

PiPlanter 2 | Plant Update and Daughter Board Migration

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First, a video:

I’ve worked very hard since my last update to move all of the hardware that interfaces the Raspberry Pi with the plants (GPIO, ADC etc) from on board the Raspberry Pi using the GIPO to a daughterboard based around an Arduino.

This has been a lot of work to accomplish, but as of about a week ago, the transition was completed in it’s entirety and everything is operating totally normally without using any GIPO on the Pi.

This provides a portability for the platform that I haven’t been able to achieve so far. As the name of the project suggests, I’ve only used a Raspberry Pi to drive all of the hardware so far as well as do everything with the software. This transition opens up the possibility of using any computer running linux to be able to drive a PiPlanter if they have the board.

I’ve outlined the “PiPlanter Hardware Specification” in the current block diagram for the project. So if you have these parts, you can make a PiPlanter. The protocol for communicating between host computer and the Arduino is outlined here. I’ve decided to go with plain text serial using a rudimentary handshake to handle the communication. Pretty much all computers have a serial port, and the Arduino is very good at dealing with it as well.

One of the next steps that I take in this project would to be to design and fabricate PCB’s for specifically for this. This is certainly going to be a challenge for me, but it’s nothing I can’t handle. This also gives me the opportunity to maybe start selling PiPlanters which is exciting. I might need to change the name for obvious reasons…

Here are some nice photos of the updated setup:


All of the code and documentation for this version of the PiPlanter can be found here.

I am going on break from school from today, December 18th 2014 to on or around January 14th 2015. Now that the PiPlanter isn’t at my house, I can’t access the network remotely and make changes to the code. The next month will be a good stress test of the new daughterboard infrastructure. Hopefully it all goes well.

Thanks for reading!

Site has been down

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You’re currently reading this via a virtual server running on top of this server, which is hosted out of my residence in southern Maine. For the most part, I generally enjoy the challenges and obstacles that come with self-hosting this website but it becomes very very annoying in cases where there is physically nothing I can do. Take these past two days for example.

Storm!

Sometimes it snows a foot in an hour and the power goes out for a few days. Not much I can do about it, sorry for the inconvenience. If it’s any consultation, Twitter isn’t hosted out of their parent’s house and you can follow me there where I typically post if my site is up or down.

Thanks for reading!

PiPlanter 2 | Python Modules & Text Overlays

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So in my last posting of the PiPlanter source code, the python script alone was 500 lines long. The intent with was to make things more modular and generic compared to the original version of the code that ran two years ago. Since the project has expanded a considerable amount since two summers ago, my goal of keeping everything short and concise isn’t really valid anymore so I’ve decided to split the code up into modules.

This improves a number of things, but it makes it kind of inconvenient to simply paste the full version of the source into a blog post. To remedy this, I’ll be utilizing www.esologic.com/source, something I made years ago to host things like fritzing schematics.

The newest publicly available source version can be found here: https://esologic.com/source/PiPlanter_2/ along with some documentation and schematics for each version to make sure everything can get set up properly. What do you think of this change? Will you miss the code updates in the body text of a blog post?

With all that out of the way, let’s talk about the actual changes I’ve made since the last post.

The first and foremost is that using Pillow, I’ve added a way to overlay text onto the timelapse frames like so:

Before

After

 

This was prompted by some strange behavior by the plants I noticed recently seen here:

I thought it was strange how the chive seemed to wilt and then stand back up and then wilt again, it would have been nice to be able to see the conditions in the room to try and determine what caused this. Hopefully I can catch some more behavior like this in the future.

Here is the new Image function with the text overly part included if you’re curious:

Now that I’ve got the PIL as part of this project, I’ll most likely start doing other manipulations / evaluations to the images in the future.

Okay! Thanks for reading.

PiPlanter 2 | Installing a 3rd Instance of the PiPlanter

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Ten days ago I finished installing the third ever instance of the PiPlanter in a lab in the physics department at my college! I went with the the rack mounted design as I did this past summer, and am going to be growing Basil, Cilantro and Parsley as opposed to tomatoes. Here are some photos of the new setup:


There are a few major changes that come with this new instance. The first and foremost being the addition of LED grow lights. I’ll post a new version of the code with LED routines included when I think it’s polished enough. The second difference is that a tray of soil is being used as the growth medium for the plants as opposed to pots of soil. This will more than likely be the configuration I use moving forward. The final difference is the actual type of plants being grown. I’m moving away from tomatoes because there will be nothing to pollinate the flowers in the winter as well as the fact that I cook a lot and it will be neat to have spices that I can use on a day to day basis.

The first 10 days of growth has gone well. Here’s a video of them growing so far:

Thanks for reading!

PiPlanter 2 | Interfacing a Mikroelektronika CANSPI and an Arduino

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The CANSPI board is a nice integration of the MCP2515 CAN Bus Controller and the MCP2551 CAN Bus Transceiver. To interface with these boards I’m using an Arduino Nano and the Seeed Studio CAN Bus Shield Library.

Here are some photos of the configuration, including the switch position on the CANSPI being used:

The wiring diagram goes as follows:

There are two parts of Arduino code, the sender and the receiver. The following code sends a sample piece of CAN data. Attach a potentiometer to A0, and twist it to see the differences in data in the receive code:

The following prints all CAN data received to the serial monitor:

Twist the potentiometer and see the change in data to see that it’s all working:

Thanks for reading!

Blink out IP address for Raspberry Pi using Python

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So in the final chapter of the long saga that has been connecting my Raspberry Pi to my Campus’s WiFi network, I needed a way to obtain the IP address of the Pi without using a display or a serial cable.

I’m actually pretty proud of this and I think it’s an elegant solution to a fairly annoying problem. Here’s a video of the system in action:

The program starts with three blinks. After that, the pattern goes as follows:

So

Etc. Four short blinks indicate a 0 and six short blinks indicate a “.”

Once the address is fully read out, three long blinks will occur.

Here’s the code:

You can make it run every time the Pi boots with:

Add the following line:

And your good to go! You can now press the button any time the pi boots to get the IP address without connecting anything!

Parsing Serial Data Sent To Arduino

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I use this code constantly. It basically packages serial data for strtok_r to split into pieces paced on predefined deliminators. Each bit of data is separated by a “,” and the end of the set of data is a “.”

If you send in a string like:

You can split it into three varaibles that equate to those different values. In this case:

The Variable x would equate to 10.

Here’s the code:

Here’s an example.

Say you have a serial device hooked up to your softserial port and in inputs “10,50,100.” to the arduino to be split up. If you want to set each of these numbers to separate integers and then print them to the serial console, you’d do it like this.

PiPlanter 2 | DIY Lite Version Release!

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Since I returned to college the PiPlanter has been running without me having to do any maintenance on it at all. The plants are still alive and growing and all processes associated with the PiPlanter are still going. I figure now is a good a time as any to bring together all of the work I’ve done to till this point in one concise post.

This does NOT mean I’m done working on future versions of the PiPlanter. I’ll hopefully write another post stating goals for the future sometime soon. Now onto the build tutorial.

 

The Hardware

 

First, the hardware of the project. A good place to start would be the parts list:

In the previous version of the PiPlanter, I didn’t have a concrete parts list for the project. Hopefully I’ll be able to keep this spreadsheet updated if the project changes. A lot of these components are mix and match, you could use pretty much any pump (The math for volumetric pumping is done with this pump) or any tubing or any power supply that can do 12v and 5v. A computer PSU would work great as well.

This is the hookup guide for the system:

(Thanks to tamps for the help!)

The two sets of header blocks are to be replaced by the moisture sensors, and the motor replaced with the pump.

For a physical configuration, I’ve found through multiple times doing this that mounting it on a wire rack works the best as seen here:

Edit (10/19/2014) Here is the same group of plants two months later without any direct human interaction. They grew from the light in the window and used up all of the water in the reservoir which was totally filled before I left.

To distribute the water to the plants, attach the vinyl tubing to the outflow of the pump and seal off the other end of the outflow tube. Run the tubing along the plants and drill holes wherever you’d like the water to exit.

You’ll also need to install the camera module in the Pi and point it wherever you’d like the frame of the photo to be.

 

The Software

As a preface, I’d like to at first say that this software was written entirely by me. I’ve never had any formal training in programming of any kind, so if there are obvious flaws with my code please let me know. That being said, I’ve found that this system is very effective and has worked for me and kept my plants alive for months.

All of this runs off of a base install of raspian on a raspberry pi model b.

There three major parts to the software. First, the prerequisites:

You’ll need to enable SPI on your Pi in order to use the MCP3008 ADC. Do this by running the following commands:

Comment out the spi-bcm2708 line so it looks like this:

Then run this to make it more permanent.

And finally reboot your Pi with:

Then the php code that renders the pChart graph. More details for installing pChart here and officially here.

And now the star of the show, the python script:

Before running, make sure you make the following changes to the script:

You’ll need set up access to twitter API’s, seen here. You’ll need to input your information about your twitter app into into 331-334 of this script.

You’ll need to input information about your YouTube account on line 429

On line 473 you’ll need to input your mysql information.

 

Output Demos

The PiPlanter is very connected. It renders graphs of data, takes images and renders timelapse videos.

Here’s a standard tweet showing the plants:

Here’s a tweet showing a day’s worth of data in  a  graph render:

Here’s a tweet showing a week’s worth of data in a graph render:

Here’s a timelapse video of three days:

Follow @PiPlanter_Bot for updates on my plants.

That’s pretty much it! Please feel free to modify this code for any use you’d like.

All of my research on this project can be found here.

Thanks for reading, and please leave a comment if you like my work!

PiPlanter 2 | Updating Dependencies

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In addition to the directions in this post on getting the ADC working, the following must be run to get the current version of the PiPlanter up and running.