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IOT Projects

Raspberry Pi Project 02 – Ad Blocking DNS and DHCP

Ramen Junkie 1Comment

Raspberry_Pi_LogoI’ve been at a bit of a loss for a while on what to do with my RaspberryPi B+.  I have a B+ and two RaspberryPi B 2s.  The B2s are so much more useful and powerful than the B+ that the poor B+ has kind of been tossed to the wayside.  I was using it as a server for ZNC, an IRC Bouncer.  When I set up my milti-monitor set up, I tried running X-Chat on the B+ with ZNC but the lag was too much.  I’m not sure if the load was from XChat or from ZNC or from Synergy, but the short of it is, the B+ wasn’t useful to my array of machines and needed a headless activity assigned to it.

Sure, I could let it continue to run ZNC, but dedicating two Pis to IRC seems like overkill, so I moved ZNC to the B2 that I run Xchat on and freed the B+ for whatever I wanted.

Pi-Hole for DNS

I started out by setting up Pi-Hole.  It has a fancy name and is simple to install, but at the core, Pi-Hole is just a DNS server that filters sites based on some predefined public lists.  Specifically, it filters ads.  There is a whole debate to be made on the pluses and minuses of ad filtering, but it is what it is and I’m not getting into that debate here.  Pi-Hole has a white list anyway, for “good ads”.  Mostly, it’s a way to filter on mobile, where it’s not easy to install an ad blocker.

Installing Pi-Hole is as simple as entering the following into the command line over SSH or even on the RaspberryPi itself:

sudo curl -L install.pi-hole.net | bash

Though you will also need to set up the Pi with a static IP and then later point your computer’s DNS records to the IP of the Pi.

On a bit of a side note, DNS is Domain Name Server.  The easy analogy is that it is a phone book to the Internet.  Servers where websites live all have IP addresses assigned in various ways, but in order to keep things simple for humans, these servers get friendly names, like Microsoft.com or Facebook.com.  The DNS is where your computer looks up “Facebook.com” to find out what IP address it’s located at.  In this case, ads come from specific servers and providers, often not related to the core domain.  So Website.com may serve ads from advertiser.org.  With Pi-Hole, your computer looks up both domains when you connect to Website.com, but the RaspberryPi Pi-Hole simply replies “I don’t know where Advertiser.org is located”.  You computer then fetches what it can from Website.com, but displays nothing from Advertiser.org.

ISC-DHCP for DHCP

Sort of tangentially related, I recently changed ISPs.  I went from a 3Mbps DSL to 50Mbps Cable modem.  I keep my home network crazy organized since there are a ton of devices on it.  For every person in my house there are something like 4 devices, and this doesn’t count game consoles, media devices, or my own little IOT devices.  On the old modem, I set up MAC assignments on the router so that wireless devices like my phone, where I can’t assign a static IP, get assigned a specific IP.  I went through and set all of this up on the new modem, but none of the assignments seem to have taken.  I’m not entirely sure why, I have theories, but I’ve instead decided to use this as an excuse to re-purpose my B+ and to learn more about managing a DHCP server.

So what is DHCP.  DHCP stands for Dynamic Host control Protocol.  I mentioned earlier that DNS was the way to connect the firstly domain name to an unfriendly IP address.  DHCP assigns those IP addresses.  Some static devices like routers or desktop computers that never go anywhere can pick and self assign an IP but things like phone that move between networks need to be given a temporary IP address as they come and go.  DHCP handles this.  Every device on a network has a unique IP address, though small networks like the one in your home, all tend to share IP ranges since to the outside world they appear to be one node/thing/device.  DHCP can be used to give out reserved “static like” IPs to these roaming devices though based on the device’s MAC Address.  A MAC Address is a device unique identifier.  For example, when the DHCP server or router sees a specific MAC, it can say “I know you, you get IP 192.168.1.50”.  When a strange device shows up, it will simply say “Here, this time you are 192.168.1.103, which is the next free IP in my pool of IPs”.

The set up for DHCP is a bit more involved than for Pi-Hole.  There is a detailed guide below but I’ll run through the cliff notes version.  There is a lot more that can be done but I’m not going to get super detailed here.  This is essentially for a simple home network with one subnet.  The first steps are to set up and configure the server, it will likely error out in the middle, just keep going with it.

sudo apt-get install isc-dhcp-server

sudo nano /etc/dhcp/dhcpd.conf

This is where it gets a little trickier.  You will need to edit the options in the config file.

option domain-name “your_domain”
option domain-name-servers

Your Domain can be more or less anything really, it’s often just “Workgroup” by default in Windows.  It should be all one word though.  Domain Name Servers are specific however.  If you are using Pi-Hole, set the IP of the Pi running Pi-Hole into this list.  You can add additional DNS servers with a comma between each one, some suggestions, 8.8.8.8, and 8.8.4.4 are Google’s DNS servers.  OpenDNS uses 208.67.222.222 and 208.67.20.220.  It’s a good idea to have more than one in case there are issues.

The only other thing you NEED to set is the ip information and range found under

subnet 10.0.0.0 netmask 255.255.255.0
{ range  10.0.0.1 10.0.0.200;
option routers 10.0.0.254;
}

You will need to replace the IP information in this block.  the subnet should be the first three octets of your network followed by a .0.  The most common ones in a home network are 192.168.1.0, 192.168.0.0, and 10.110.1.0.  The range is the range of IPs to give out.  If you are going to use static IPs, i would recommend setting this range beyond your static IP ranges.  For example, I have a spreadsheet blocking off reservations through 192.168.1.100, I added some extra for my router to serve as a backup DHCP server and set the range on the RaspberryPi as 192.168.1.175 192.168.1.250.  This means, when a device connects, it will be assigned an IP starting at the next available at .175.

The final option is routers, chances are really good that you have only one, and chances are the IP ends in .1 or .254.  This will assign the router IP so that devices know how to get out to the Internet.

If you want to ensure your Pi DHCP server is assigning IPs over anything else on the network (ie your router) you will need to find the line that reads “If this DHCP is the official DHCP server…” and uncomment the line “authoritative”.

Finally at the bottom, there are blocks to assign static IPs using a format like:

host MACHINENAME
{
hardware ethernet MACADDRESS;
fixed-address FIXED_IP_YOU_WANT_TO_ASSIGN;
}

An easy way, if you are running Windows, to find out MAC addresses of devices is to run Netscan.  This will give you a list of everything connected to your home network.  There are a few ways to decipher which IP/MAC is which.  Some will have the MAC printed on them, often near the network port.  In the case of phones or tablets, it’s simplest to simply disable the WiFi or turn them of and rescan to see which disappears.  Some may show up with names you may recognize.  You can also sometimes search for the first 3 sets of numbers (IE 45:3b:a3) which is manufacturer specific to decipher that “That’s a Sony device, the only Sony thing I own is the Blu Ray player”.

Setting reserve assignments is entirely optional.  The main purpose is to better organize your home network.  If you only have a half dozen devices, it really probably isn’t necessary at all.

Once you are done editing, CTRL+O (for Output) to save the file, and CTRL+X to close it. If you get an error that you can’t write the file then you forgot to do a”sudo” and you will need to do it all over again.

Wrap Up

Things are not quite finished yet.  You will need to start the DHCP server, since it error-ed out earlier.  You can do this using the following commands:

service isc-dhcpd-server stop
service isc-dhcpd-server start

HOWEVER, I still got an error when I did this.  A little searching and I found a similar issue and fix which I used.

sudo pico /etc/default/ifplugd

Then change this:

INTERFACES=”auto”
HOTPLUG_INTERFACES=”all”
ARGS=”-q -f -u0 -d10 -w -I”
SUSPEND_ACTION=”stop”

To match this:

INTERFACES=”eth0″
HOTPLUG_INTERFACES=”eth0″
ARGS=”-q -f -u0 -d10 -w -I”
SUSPEND_ACTION=”stop”

then reboot and after the reboot start the server with:

sudo reboot

service isc-dhcpd-server start

Everything should be working now.  You can run Netscan later and see if IPs are being assigned into the range you chose.  This may not happen immediately since IPs have a lease time and devices may hold on to the old IP for a bit.

Reference:

Pi-Hole

Configuring the Raspberry Pi as a DHCP Server under Raspbian Wheezy

How To : Use The Raspberry Pi As A Wireless Access Point/Router Part 3…B!

IOT Projects

Fixing my CHIP

Ramen Junkie 0Comment

chiplogoI mentioned getting my CHIPs from NextThing aq bit ago, but I have not really done much with them. I noticed a bit of an issue keeping them powered when I set them up and assumed I had been using a power supply that wasn’t ideal. I believe it was the one off of the Chromecast on the TV, just because it was handy. It turns out, this is not the case, there is actually an issue with the software of the CHIPs that have shipped so far. I don’t beleive it affects all of them but it’s probably a good idea to update anyway.

It’s a pretty simple process, you can review the boot repair process here. The main issue you may have is that it requires you be running Ubuntu (or really just Linux). You can get a live image and load it using a USB drive though, and being familiar with Linux is useful for working with the CHIP itself since, it runs Linux.

I’m already running Ubuntu on my Laptop, so no issues for me there, my issue was actually getting something to short the pins for FEL mode. I didn’t have any breadboard wires handy at the time. I tried a paperclip as suggested but it was too large to stick in the pin holes. Instead I found a piece of wire to strip off. The point is, almost any melat strip would work to conduct between the pins.

You may also want to try flashing the whole image. Details on this process can be found on the NextThing’s website. It’s the same basic process of fixing the boot but you need to do more work yourself instead of just running a pre made fix app.

I’ve been trying to find some good plans and ideas for my CHIPs. There are some good ideas listed here.

I wanted to try turn a USB camera into a Streaming camera, but I can’t locate any of the USB cameras I used to have.

This Web and Bluetooth Sniffing device seemed neat, though once I started looking at it it looks more like it just tracks Wireless APs in the area, I’m more interested in building a network monitor.

This homemade Amazon Echo clone is pretty neat, and seems like an interesting project to work on that involves some hardware set up as well as software.

IOT Projects

Microsoft’s Windows Remote Arduino Experience Test

Ramen Junkie 0Comment

I found a couple of Arduino apps in the Windows 10 App store recently, both put out by Microsoft.  There is an app that allows your Windows Phone to act as a virtual shield for an Arduino board which I ave not tried yet, but I set up and ran a quick test of the second app which lets you remotely trigger and monitor the pin inputs and outputs.

I set up a simple circuit with some LEDs on pins 2, 3, and 4, and toggle them from my desktop using the app.  There isn’t any special code needed for this, the Sketch used is the StandardFirmata sketch listed in the Arduino app under the example sketches.

There doesn’t seem to be a lot more that can be done with this app.  As far as I can tell, it’s not really set up for any sort of customizing such as naming the triggers or causing any sort of action to be taken when a trigger is activated on the Arduino (such as pressing a button to open a URL).

There is some additional information available from Microsoft about setting up Visual Studio to build Arduino projects but I have not tested it yet, I actually have run into an error in Visual Studio when trying to load the projects.

IOT Projects

CHIP – the $8 Computer

Ramen Junkie 3Comments

CHIPS!I just want to start here by saying CHIP is kind of a shitty name for a computer thing, there is no effective way to do any sort of search for “Chip computer” since “computer chip” has been a thing for eternity and gives the same results. This thing really needs a re-branding or something.

I’m also not entirely sure it’s still an $8 computer, It looks like they are charging $9 now on their website, and there is shipping costs involved.

Anyway, I’ve received two of these cheap computers from my Kickstarter contribution. I have a third one coming in 4-6 months that will include a VGA adapter. For some reason all of the peripherals are delayed. I wanted to get a December release CHIP and they offered the option to buy more once the Kickstarter ended, so I ended up with two.

CHIP is essentially a micro computer in the vein of the Raspberry Pi, though it’s more like a Pi Zero than the larger models. The main advantage the CHIP has over the Pi Zero is that it has built in WiFi and Bluetooth.

I’m not entirely sure what I want to do with these yet, though I have some ideas. They are almost as cheap as my Arduino clones (probably cheaper once I add WiFi to an Arduino), and they have a slightly more versatile interface since it’s running Debian Linux. It would be really simple to add a basic web server to this device.

The board itself seems sturdy enough. It comes in a plastic cradle that covers the bottom and three of the 4 ports are on one end which is convenient. There is a normal USB port, a micro USB for power, and a headphone style jack that has an A/V breakout cable to hook it to a monitor and speakers. The molex style battery connector is on the opposite end. The base set up only has composite output for video, the breakout cable gives you a standard Red, Yellow, White set of hook ups.

CHIP Desktop

I hooked both of my CHIPS to a TV so I could easily connect each to the WiFi in my house. Once they are online the video isn’t really necessary since I can SSH to them over the network using Putty.

On a side note, the default SSH log in information is username: root, password: chip .

I have not done much else with it yet, but it’s a nifty little device. I have a vague idea of building a Podcast radio for my car out of one with some push button controls but I have not checked if there is a CLI based podcatcher available, or even a CLI based audio player I could tie push button commands to.

IOT Projects Programming Projects

Pushing Arduino Data to MySQL via PHP Part 2: The Server

Ramen Junkie 1Comment

tempdataIn the last post, I talked about how to send data from the Arduino to the MySQL server.

Today, I’ll cover how I’m receiving and displaying that data on the server side.  I’ll put the code for the webpages into this post but I’ll put everything together in a nice little package at the end of everything.  I mentioned last post that the end trick was to let the server worry about processing the data instead of the Arduino.  I’m running this on my NAS but it could be run on any standard web server with PHP and SQL.

For the purposes of this code, I’ve placed the files in a directory called “temps” on the root of the web server.  If you want to put them elsewhere, such as “temperaturelog” or “home/temps” or wherever, you’d need to alter the code of the Arduino in the previous points to replace the temps directory with the directory you plan to use.  I’m going to assume that the reader has a basic LAMP (Linux, Apache, MySQL, PHP) stack style server and knows the basics of how to create databases and run things on it.  If not you can Google the basic set up, though I may do a quick write up and reference it here eventually.

You’ll need to create a database called “housetemps” and import the linked structure file into it.  (If you know what you’re doing in PHP you can rename housetemps)   This will create a table int he database called “temperature” with the following columns: id, event, sensor, celsius, humidity, datestamp.  This will give you the basic structure needed to run the php code on the server.  A quick rundown of what these values are used for…

  • id – A standard auto incriminating id value for SQL
  • event – Time and date of when the event happened
  • sensor – A text based identifier for each probe.  This example uses one probe but could be altered for more.
  • celsius – The temperature reading, it doesn’t actually have to be Celsius, that’s just the default of the probe.
  • humidity – Humidity reading in percent humidity
  • datestamp – A date only time stamp, used for sorting the data when you review it later.

Now that you have the core database structure set up, the server needs to know the credentials for connecting to the database.  Since this is used by several files, it’s best to put the info in it’s own file and use an include statement int he PHP to add it.

In the “temps” directory create a file dbconnect.php and add int he following code, changing the values listed for the values used when setting up the database…

<?php
$MyUsername = “USERNAME”;  // enter your username for mysql
$MyPassword = “PASSWORD”;  // enter your password for mysql
$MyHostname = “localhost”;      // this is usually “localhost” unless your database resides on a different server

$dbh = mysql_pconnect($MyHostname , $MyUsername, $MyPassword);
$selected = mysql_select_db(“housetemps”,$dbh);
?>

Next you’ll need a way to get data into the table.  This is done using add_data.php, which is called by the Arduino in the code shown previously.

Make a file in the “temps” directory called add_data.php, and add the following code.

<?php
// Connect to MySQL
include(‘dbconnect.php’);

{
$dateget = date(“Y-m-d”);
// Prepare the SQL statement
$SQL = “INSERT INTO housetemps.temperature (sensor ,celsius, humidity, datestamp) VALUES (‘”.$_GET[“serial”].”‘, ‘”.$_GET[“temperature”].”‘, ‘”.$_GET[“humid”].”‘, ‘$dateget’)”;

// Execute SQL statement
mysql_query($SQL);
}

// Go to the review_data.php (optional)
header(“Location: review_data.php”);
?>

The code is pretty straight forward. The first section includes our previously created log on credentials.  The last section forwards the page on to review the data.  The meat is in the middle with the SQL statement.  The line $dateget = date(“Y-m-d”); creates a Year-Month-Day date for sorting later.  The next line creates the SQL query using variables passed via the url, the third part executes this query adding the data to the database.

The final piece of this whole thing is the review_data.php file.  This file displays the results in a nice looking table.

<?php
// Start MySQL Connection
include(‘dbconnect.php’);
?>

<html>
<head>
<title>Arduino Temperature Log</title>
<style type=”text/css”>
.table_titles, .table_cells_odd, .table_cells_even {
padding-right: 20px;
padding-left: 20px;
color: #000;
}
.table_titles {
color: #FFF;
background-color: #666;
}
.table_cells_odd {
background-color: #CCC;
}
.table_cells_even {
background-color: #FAFAFA;
}
table {
border: 2px solid #333;
}
body { font-family: “Trebuchet MS”, Arial; }
</style>
</head>

<body>
<h1>Arduino Temperature Log</h1>

<p>Select Date:
<?php

$sql = “SELECT DISTINCT datestamp FROM temperature”;
$result = mysql_query($sql);

echo “<select name=’datestamp’ onchange=’location = this.options[this.selectedIndex].value;'”;
while ($row = mysql_fetch_array($result)) {
$current = $row[‘datestamp’];
echo “<option value=’review_data.php?dateselect=$current’>$current</option>”;
}
echo “</select>”;
?>

<table border=”0″ cellspacing=”0″ cellpadding=”4″>
<tr>
<!–    <td class=”table_titles”>ID</td> –>
<td class=”table_titles”>Date and Time</td>
<td class=”table_titles”>Sensor Serial</td>
<td class=”table_titles”>Temperature in Celsius</td>
<td class=”table_titles”>Percent Humidity</td>
</tr>
<?php
// Retrieve all records and display them
$SQL = “SELECT * FROM temperature WHERE datestamp LIKE ‘”.$_GET[“dateselect”].”%’ ORDER BY id ASC”;

//Execute the SQL
$result = mysql_query($SQL);

// Used for row color toggle
$oddrow = true;

// process every record
while( $row = mysql_fetch_array($result) )
{
if ($oddrow)
{
$css_class=’ class=”table_cells_odd”‘;
}
else
{
$css_class=’ class=”table_cells_even”‘;
}

$oddrow = !$oddrow;

echo ‘<tr>’;
//       echo ‘   <td’.$css_class.’>’.$row[“id”].'</td>’;
echo ‘   <td’.$css_class.’>’.$row[“event”].'</td>’;
echo ‘   <td’.$css_class.’>’.$row[“sensor”].'</td>’;
echo ‘   <td’.$css_class.’>’.$row[“celsius”].'</td>’;
echo ‘   <td’.$css_class.’>’.$row[“humidity”].'</td>’;
echo ‘</tr>’;
}
?>
</table>
</body>
</html>

The core of this file was lifted from the previously mentioned guide on Tweaking4All.  The problem I had with their results was that it simply displayed an endless list.  I am polling every 15 minutes, so this list tends to grow unwieldy very quickly.  This is where the datestamp marker comes into play.  I added this little chunk of code at the top of the table.

<?php

$sql = “SELECT DISTINCT datestamp FROM temperature”;
$result = mysql_query($sql);

echo “<select name=’datestamp’ onchange=’location = this.options[this.selectedIndex].value;'”;
while ($row = mysql_fetch_array($result)) {
$current = $row[‘datestamp’];
echo “<option value=’review_data.php?dateselect=$current’>$current</option>”;
}
echo “</select>”;
?>

This creates a menu based on unique values of datestamp.  Selecting a value forwards you to review_data.php with a date attached, then review_data.php only shows data that matches that datestamp.  This allows a single day to be viewed easily.  In the future I may add a bit more to this menu, eventually, the list of dates will also become unwieldy in length.  I also plan to run numerous sensors at once with different names so I’ll likely also add a second menu so the list can be sorted down by sensor name.

I’m also looking to add a bit more functionality to the code in the form of a graph, so it will be easier to see trend lines in the data.  The data I have now is from my office, in a well insulated basement room, so the trend lines are rather boring, but when there are several sensors in different rooms in the main area of the house, or even outside, this data becomes more interesting and useful.  I’ll go into this at a later day though…

 

 

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