Monday, October 27, 2014

"Thin Client" Usage

In addition to the modern "thin client" platforms of Chromebook and Chromebox (a laptop or small system running the Chrome operating system), I have a number of older thin clients running Windows CE (Compact Edition). A thin client is a small system designed without much processing power, which connects or remotes over the network to larger, more capable computer system(s) where the work is done. The WYSE (now owned by Dell) "WinTerm" (Windows Terminals) I will demonstrate here usually used the Remote Desktop Protocol to connect into a Windows workstation or server.

The WYSE terminals are running Windows CE from a "disk-on-a-chip", meaning there is no fan or other moving parts. They are powered by 12VDC, drawing slightly over an amp of current when running. For connections there is a VGA port for video, PS/2 ports for the keyboard and mouse, two serial ports, and a parallel port. VGA video is able to display up to 1280 x 1024 pixels, but just as importantly, 640 x 480 pixels that small economical LCD screens can have as input.

In the workplace, I've set up four WT3125SE units for provisioning DSL modems. A basic version of Internet Explorer 6 is in Windows CE, and there is an additional TELNET program that has the ability to run scripted commands. In short, providing everything needed for the task, with no extras. The WT3125SE has a Geode 1 CPU running at 266MHz, and 64Mb RAM. USB ports are version 1.1, and there is only a speaker jack for external sound output.

I have more of an expanded version that really improved upon the 3125, the WT3150SE. The Geode 2 CPU operates at 400MHz, and it has double the RAM at 128Mb. USB ports are the faster version 2.0, and both a stereo output jack and a microphone input are present.  The terminal software is able to establish an SSH connection, so I use one of them in my office to connect to our core router, as well as console cables from the serial ports to configure smaller network equipment.

In later posts I will cover an intended use as an environmental sensor host in a room, interconnected through the house, most likely also trying to use it as an intercom system. Since the terminals are connected to an Ethernet network, they can be remotely powered on by what is called a "Wake on LAN" signal. For now, here are some pictures of the units I have in my office (sharing the same keyboard, mouse, and monitor through a KVM switch, the WT3125SE has the yellow power button).

Friday, October 17, 2014

20 Volt DC Expansion

Now that we have covered 5 and 12 volt DC power applications over USB and Ethernet, this post will be about 20 volt DC expansion. This voltage is very common for laptops and Chromebooks/Chromeboxes. It is important to note that some name-brand manufacturers will have a third 'sense' wire in the power cable, to ensure that a no-name or incorrect wattage power supply is not used with their systems.

A good example is my Dell Precision 6500, which has a comparatively large (and more expensive) power supply for a standard-sized laptop/dock. A more-common Dell laptop power supply has the same plug, but I am warned that the wattage is not sufficient if I use anything other than the 210 watt unit that is designed for it. At 20 volts, that wattage means more than 10 amps of current, a phenomenal amount that I do not have the answer as to why the laptop needs so much (the battery, with nice LED level indicators, has always lasted me about two hours of use away from the dock).

I have an extra supply, that had its cord cut by my boss of the time, thinking that the unit was bad. As you've learned by now, I then think of ways to put it back into use. You should also know that I have too much of my Dad's blood in me, and that we never thrown an item away in the hope that we can fix it later.

My ASUS Chromebox in the office is also 20 volts DC, a power supply that is half as large. It has a very-common 5.5mm x 2.5mm (the same dimensions of the power plug for older Roku units) plug for power, without any 'sense' line. In addition my Lenovo 11e Chromebook and my wife's Lenovo convertible laptop/tablet also have 20VDC power supplies, a fifth of the size of that of my Precision. I have an adapter plugs set that I should have covered in earlier posting, in that they have the common 5.5mm x 2.1mm jack inputs, and convert it into all of the plugs I will use on this project.

Here are the pictures:

Sunday, October 12, 2014

Security Camera and DVR Installations

For this article, I will provide some information about the four-camera DVR security systems I've installed at both my parents' residence and my home. I'm not going into details of where each picture is, save that both locations always are recording, able to run during a power outage, can easily provide playback, and are remotely accessible. In the case of the DVR for my house and office (which is an "IP Camera", which will be covered in a separate article), I am able to view live content from my smartphone.

Several months ago, Google bought out a camera manufacturer, which they likely will be promoting later. From what I previewed, despite the ability to save video to your Google Drive, each camera was a separate system, and more expensive than what is available elsewhere. I've taken the route of an inexpensive DVR that has enough functionality, able to use common exterior cameras with infrared capability (meaning no additional lighting for grayscale video at night).

The power requirements for the DVRs and cameras (I will say that the unit my parents have doesn't have the smartphone capabilities mine does, nor is it needed there, although brand is the same) is 12-volts DC, which as you know has a common ring for the other equipment I have. There are common terabyte drives on the DVRs, able to record full-time for over a month with four cameras. Playback is easy to do, by just selecting the segment you want to view, either locally or remote over the Internet (access is password-protected, and generally only older Internet Explorer browsers can be used if they do not have the DVR software installed).

If you have an area beyond 20 feet that needs to covered at night, I've also set up additional IR assemblies to add night illumination. The IR LEDs do not give visible light, someone within 25 feet only sees red dots on the camera or additional lamps. A sensor turns on the IR LEDs in low-lighting situations automatically.

Here are a few pictures, exterior camera (and additional IR LED lamp), a dome camera (the comparable IR LED unit looks the same as the camera), and a wall plate close to one of the DVRs, carrying power to the cameras, an Ethernet link back to the DSL modem, and BNC connections for each of the four cameras. In a later article I'll show the cables commonly used and more details.

Friday, October 10, 2014

Power over USB

In addition to PoE (Power over Ethernet), I commonly power 5VDC devices from an Anker 5-port USB charger. This has the benefit of very stable voltage supply that replaces up to five separate "wall-wart" supplies. I use one both in the office and at home, and have powered Roku players of different generations (the Roku 3 needs a 12VDC supply, but all of the others are 5VDC), Chromecasts, HDMI switches, Harmony hubs, and USB speakers (I charge my cell phone from a stand on my office desk that has the USB sync cable plugged into the VisionNet M505N DSL modem).

Here are photos showing the Anker charger, an adapter cable I found necessary for the earlier Rokus (they use a 5.5mm x 2.5mm power jack), and a volt/current meter for seeing how much power a USB device is using. The older Anker chargers I have are fuse-protected. If you blow a port out, Anker will provide you a free replacement, the new design has auto-resetting breakers.

Thursday, October 9, 2014

DIY (Do It Yourself) PoE (Power over Ethernet)

I've used this so far to supply power to remote devices like VisionNet modems re-purposed into Wireless Access Points (WAPs), DSL modems, and IP cameras. A basic voltmeter is helpful, as it allows you to troubleshoot and calculate voltage drop across the Ethernet links you set up. Of course I'm going to say the standard disclaimer, what you do is at your own risk, if you aren't careful you will release the "magic smoke" out of your device.

I like working with these parts because it is non-standard PoE voltages (12V DC instead of 48 volts), and has conventional connectors that are easy to source. In fact, I am in the process of setting up a 12 volt "rail" at my house (more on that in a later article) for powering all the Internet access equipment and my security cameras and DVR. The 12 volt supply is battery-backed (no, not a car battery, though it could be) so it operates for a time even if the AC power is out at my residence.

The first picture is the components for a single PoE cable to power one device. "Barrel" connectors used for device power are standard 5.5mm OD (outside diameter) / 2.1mm ID (inside diameter). Many devices, including the BEC DSL modems, VisionNet M505, and M505N modems use that connection for power, however you may need an adapter if your equipment uses something different.

Your power adapter is plugged into the connection on the lower left of the picture, the Ethernet connection above it plugs into the Ethernet switch or modem that is the data source. On the right of that lower cable assembly you have an Ethernet cable plugged in that runs to your device. Keep that cable as short as possible (even though many power supplies actually provide more voltage than needed) so that the voltage drop isn't too significant (I've used lengths of 25 to 50 feet which can easily carry 12 volts).

The upper cable assembly in the photo is at the device, your Ethernet cable plugs into the end on the left-hand side. Connections on the right plug into the device. You may want to rig up a cable lead (at the device) that is able to check the voltage level when the equipment is powered up when first installed. You will probably need one of the upper cable assemblies (they are sold as a set, and I haven't found a source that sells the ends individually) for the next component I will describe: PoE powering up to four devices of the same voltage.

The second picture shows that component, although it isn't marked there for the connections (the far side Ethernet ports are to your LAN / switch, towards the front are to the devices being powered by PoE). On the board itself it wasn't marked for the blue connection for optional power (I use it for equipment local to the board that are also 12VDC), the most inboard terminal is typically positive (most "barrel" power connections have the center pin as positive, and as shown there is a 5.5mm/2.1mm barrel connection on the board for that easier use), and the outboard terminal is your power supply ground.

Make sure you have a power supply for the summed current of all connected devices (each modem or device powered by 12VDC is usually an amp of current, and it will be marked on a label on the device). In the office I have an 8 amp supply, and my 12 volt rail at home will be able to supply at least that as well. As I said, you will need one half of the cable assemblies at the other end to break out the power to the device.