Short Throw Projectors and Wall Mounts

Once upon a time, budget projectors suitable for classrooms all came in budget configurations. They were all intended for ceiling mount with a distance to the screen of 2.5 – 3 metres. If you wanted to come in closer than this, you either paid a lot of money for an odd looking Sanyo, or you spent still more money on something much bigger and spent half your IT budget for a year on a special short throw lens.

Times change, and the advent of interactive whiteboards and other special situations, has seen a spate of affordable short throw projectors appear recently at the lower end of the price range. If you can cope with a distance of about one metre, Epson, Toshiba and the like have models around NZ$2000 to catch your interest. This sort of throw makes it possible to mount these projectors on an arm screwed to the wall, rather than lowering them off the ceiling, which works well in a variety of situations where the ceiling mount is difficult to manage, or too high. Projectors in this price range also have other nice features like network cable connections that allow software based remote control out of the box, and status reporting.

When we purchased our Epson EMP-400W, which fills an 84 inch screen at about 1 metre, the manufacturer’s official arm for the projector cost around $600, which is pretty steep compared with $100 that you can pay for a good quality no-name ceiling mount these days. However, Ingram Micro have just started to distribute projector screens and mounts by Herma, an Australian company which produces a range of well engineered items, including a short throw wall mount arm called the Teach-It 2C141. This is a chunky beastie which hangs off the wall and will hold the projector out at any distance up to about a metre. The RRP at the time of writing was a bit over NZ$400 (incl GST), which compares favourably with the official Epson product and it is a far simpler solution than making your own, an option we considered.

This is a simulation of how the thing is going to look on a wall (Just pretend that you aren’t going to mount it two inches off the floor). The plate you can see on the left needs to be screwed into solid wood (or concrete), and pretty well too, because the weight of the arm and projector are a significant loading cantilevered out like this. In deference to this, the mount is rated for a maximum projector weight of 10 kg, in part due to the weight of the arm’s own projector carriage. There is a neat plain white cover that goes over the plate when it’s mounted. I was somewhat taken aback by the size and weight of the thing – as shown above it is pretty big compared to the projector (which itself is a typical desktop size). The boom measures about 1.2 metres long, 100 mm high and 50 mm wide. The wall plate is about 700 mm long and 180 mm high. These people don’t do things by halves. Most of the metal in this thing is solid steel up to 3 mm thick. The boom is thinner and lighter, but that wallplate is solid and even the projector mount is a heavy, bulky behemoth with a dozen or more screws, each going into threaded bosses welded in place, making sure it stays together. Basically you attach the wallplate to the wall, then bolt on the boom, which can be at 90 degrees, or tilted down somewhat. The projector mount then slides onto the end of the boom, and once set at the right distance, is held in place by a set screw. Below is a closeup of the mount carriage attached to the EMP-400W.

Most projector mounts I have ever seen boast the ability to conceal cables. But in the majority of cases this is not so easy to achieve, particularly in our scenario where we have a VGA cable with pre fitted plugs which can’t be taken off. The 2C141 stands out as a mount where anything that will go through that massive boom and a 45 mm diameter entry hole on its underside (big enough for many types of plug, including Aust/NZ 3 pin mains) can be nicely tucked away out of sight inside. There is enough of a gap at the junction of the arm onto the wallplate for plenty of cables to get through. If you’re putting mains and low voltage cables inside the boom together, to comply with NZ electrical regulations the mains cable should be separated from the other cables (e.g. using a plastic duct). You should use a mains lead of at least 2 metres. The Epson comes with its own 4 metre lead, but having diverted this to other uses, we were unable to obtain generic substitutes with the figure-eight 2 pin appliance connector longer than 2 metres. For projectors that use an IEC connector, leads are readily available up to 5 metres or longer. Ideally your electrician should be able to mount a mains socket directly above the bracket on the wall.

Since Herma did not supply us with installation instructions, the following appears to be an approximately correct sequence for putting the mount together and installing it:

1. Attach the mounting base to your projector. This can be quite tricky if the mount holes are close together. The Epson has five holes, while the mount can attach to four. Generally I prefer to balance the mounts as much as possible which depends on the weight distribution across the projector – typically the lens is at the heavy end. On this mount the balance doesn’t matter so much as it does on a $100 ceiling hook. Four screws are supplied for the mount and they fitted the Epson exactly, but if they don’t you will have to supply your own.
2. Attach the mount base to the carriage (the part that hooks onto the boom) with four bolts supplied.
3. Attach the wall plate to the wall. Use appropriate fastenings, I should think at least four of.
4. Attach the arm by the lowest pair of screws only and let it hang down. Thread the cables through from the top.
5. Bring the arm upright and insert the upper pair of side screws. If it is not tilted then put in the top centre screw that stops it from angling down.
6. Fit the wall plate cover over the boom end and slide it down to the wall and press into place. You will have to thread the cable ends through it.
7. Slide the projector carriage onto the boom and temporarily tack in place with the locking screw.
8. Attach all the cables and power up the projector.
9. Adjust the projector carriage and mount for angles, distance etc. The Epson doesn’t have an optical zoom so the carriage must be moved in and out to set the picture size. There’s plenty of adjustment in the carriage for tilting the projector up and down or sideways.
10. Secure the locking screw to lock the carriage into place.

What’s the score? If you must have a wall mount, the 2C141 is worth every cent. The only problem I have with this thing is its size, which could be a bit dominating for some people. If you aren’t put off by that, it is a great solution for a wall mount out to about a metre. At this stage I still have to install it, but that looks to be a relative formality. Hats off to Herma for making such a well designed and constructed you-beaut product.

Network Cable Connectors: Can the design be got right this time?

The shift to 10 Gigabit networking presents an opportunity for the industry standardisation bodies to rectify two glaring inadequacies in the design of the standard data connectors which are based on consumer telephone equipment and as implemented are, by design, clearly unsuitable for professional uses to which they have been put in the case of computer networking since the widespread change from coaxial to twisted pair cable.

The first problem with RJ-45 connectors is that they have a snaplock fitting which breaks off easily. Coming from a background of experience with the XLR and similar pro grade audio connectors which have properly designed snaplocks that don’t break off, and more particularly aren’t prone to getting caught in other cables, clothing or any manner of other things and broken off that way.

The second lesson the IT industry needs to learn from professional audio experience is the matter of the plug gender. For unfathomable reasons, there is only one kind of plug that can be fitted on the RJ 45 patch cable. Every piece of equipment is fitted with female sockets and every patch lead is fitted with male plugs. Thus, you get the situation where any cable can be plugged into any two sockets on the same network switch, creating a loop situation. The pro audio industry, long ago, dealt with their equivalent by reversing the gender of input and output sockets. For example, a signal output on a piece of equipment is typically a female socket, and a signal input is typically a male socket. Inadvertent connections of a cable to the wrong socket are avoided thus. The IT industry should have switches fitted with one gender of connector, NICs fitted with the other type of gender, and cables that have a male plug on one end and a female plug on the other. Thus the common and loathsome cable loop is avoided.

10 Gig will use new types of connectors because the ubiquitous cheap and nasty RJ-45 is inadequate at such speed. I hope the standardisation gurus resist the call for backward compatibility and produce a much better design this time around. Backcompat is actually not very common in the industry (for example, SATA is totally incompatible with IDE, PCI-E is totally incompatible with old PCI) and therefore is not worth bothering with.

April Fool

At least two weeks ago I took my keyboard apart to clean it, and only just discovered today, weeks later, that the / and * key on the keypad are swapped around.

Easter is upon us and I’m off for a well earned break. The next lot of photos in my album are likely to be a bit more exotic than what normally appears. This is a great moment to wish any readers (?) a happy and safe Easter, and all school employees and the kids a good holiday.

The Big Stuff: Exchange, ISA, Sharepoint, Terminal Server

It so happens that last year we had a bit of a change of scenery at our school. Our faithful volunteer Linux sysadmin, who happens to be the system architect of a well known software development platform, decided to bow out because all his kids have gone through school. This set the scene for us to complete our transition to the Evil Empire and become an all-Microsoft site. But alas, our quest for World Domination was thwarted last month when someone bought a Mac :)

Anyway, we decided that the Next Big Thing at our school was to get a new server with the four aforementioned applications on it, at least that was the plan of the time. Subsequent experience has proved that:

• ISA 2006 can only run on 32 bit Windows Server 2003, while Exchange 2007 requires 64 bit Windows
• Sharepoint and Exchange Outlook Web Access conflict with each other
• And of course, as we already know from early testing, trying to get PHP installed on a DC is troublesome. This is not strictly relevant but there is an indication of just how many web applications can conflict with each other and how difficult it is to try to nail down the cause.

These two situations have forced a rethink and the need for an additional server to run the ISA firewall. While this could be virtualised, I don’t think Hyper-V is mature enough yet, and I prefer a hardware server to run the firewall as it is easier to configure than virtual networking interfaces. So the old Linux mailserver will be pressed back into action as the firewall box. But this will mean a delay in getting that firewall up and running until after the mail has been transferred over to the Exchange server.

Sharepoint is a new technology in our site and the extent of its utilisation is unclear. I am setting it up on one of our DCs for the time being and if things develop we will look at options. The DC installation caused its own little drama when the config wizard failed at step 5 with “An exception of type System.Runtime.InteropServices.COMException was thrown. Additional exception information: Class not registered”. To resolve it, permissions need to be modified on C drive according to this blog post:

• On C:\
  • Local Service account: Read & Execute, List Folder Contents, Read
  • Network Service account: Modify, Read & Execute, List Folder Contents, Read, Write
  • WSS_Admin_WPG account: Full Control
• On C:\Windows\Temp:
  • Network Service account: Full Control
  • WSS_Admin_WPG account: Full Control
  • WSS_WPG account: Read & Execute, List Folder Contents, Read

In our case the second lot of settings were already in place especially as some are inherited. It was a relief to find that blog after a lot of searching because, as he says, Microsoft doesn’t seem to be able to help solve the problem. For me it is another example of, like the PHP problem, like the Vista mandatory profile problem, how frustrating permissions issues can get on a server. Phew! that one fixed the problem and now Sharepoint is on its third server and finally one where I can leave it for a while without all the hassles that the other servers have caused us.

Once I had got the Sharepoint installation off GW01 I then had some extra work to get OWA going, as it should work right out of the box with a Client Access role installed in ES2007SP1. I found this article on the MSKB telling me that I should reinstall ISA and the Client Access Role of Exchange. Well, being of course of a mind not to go through the hassle of reinstalling Exchange again (which I have already had to do once), I decided just to skip to Step 4 and recreate the virtual directories in the EMS. These commands had to be run on the Exchange box rather than my desktop. Then I went to IIS and started the default web site. Once this got running, OWA worked. At last :)

The next bit is to get Terminal Services Gateway Server, at least, tested to see if there is a problem running it on the same box as Exchange. I don’t think this will be such a problem as Sharepoint, which practically takes over IIS. It’s no real wonder then that there was that problem, but also it’s disappointing that there is no documentation from MS for it. Not everyone can afford to fork out $$$ for a new box and licenses to run every little thing on its own server. So hopefully it will work, and then we get the professionals in to set up the HTTPS side of things (OWA, TSGS) as well as what is needed to get the SMTP server running. But it won’t be switched over until I’ve got everyone’s Exchange accounts set up, and then I have to transfer all their mail over before we turn the old server off. That’s another term away…

UPDATE: I put in the link to the MSKB article that tells you how to recreate the virtual directories using the Exchange Management Shell. On the page, this is Step 4 of the section that is specifically for Exchange 2007. One of the reasons why I want Sharepoint on another server is that Microsoft doesn’t make it at all easy to manage your disk space if you have multiple disks; they simply do not provide any setup options at all that allow you to choose where Sharepoint stores its stuff (like the database) and I don’t want it on a limited C drive partition where it can fill up and interfere with the basic server operations.