Weekend Gadgetry; DIY 3G for iPhone, Makerbot Finally Built

I spent my weekend doing a lot of geeky stuff. The two high achievers were: 1) Getting my iPhone to have always-on internet despite not having a Data Plan (kinda), and 2) Getting my Makerbot working at last, and making a few test prints.

Firstly, I’ll reveal my ingenious hack for the iPhone. Actually, it’s pretty simple, and possibly already done elsewhere. Anyway.

Personal Area Network Hack

If you have a mobile broadband modem for your computer, and you’re using a Mac, follow these instructions and you’ll have yourself a personal Wifi network for use with your smartphone, book reader or other-laptop in less than a minute, with only one free install.

1) Download InsomniaX for your mac. Because Apple can be idiotic sometimes quite often about permitting Users to do what they like with the hardware they fairly purchase, there’s no inbuilt feature to prevent the laptop from sleeping when you close the lid. This app allows you to toggle on/off this feature. Necessary to go wandering around with your hacked wifi PAN.

2) Fire up your Mobile Broadband, ideally using a USB extension cable so the Modem isn’t poking out the side of your computer so much.

3) Go to your Wifi bar at the top of the screen, click it, and choose “Create Network…”. Using default settings (Channel 11/Automatic) and a name of your choice should do. No spaces here, please.

4) Go to your System Preferences from the Apple Menu in the top right. Choose “Sharing”. From the list of options on the left, choose “Internet Sharing”. In the dropdown menu for “Share your connection from:” choose your Broadband connection/modem/device, then select Airport in the menu below. And optionally Ethernet or whatever if you need other options. Then simply check the box next to “Internet Sharing” on the left, and click “Start” when it asks you if you’re sure.

5) Connect your mobile device to your new network, and let it self-assign IP and settings. It should be able to connect once it’s adjusted. Now, you should be able to close the lid on your laptop without interrupting this networking, and put the laptop + modem-on-cable into your bag like so:

My Macbook with Huawei modem on a USB cable; the blue light indicates 3G/HSPA.

Proceed to enjoy your new personal Wifi network! It’ll last as long as your battery does, which for my macbook is pretty formiddable. I imagine if you do something similar with a decent netbook you’d get a good 5hrs out of this with the screen/HDD disabled.

Something to watch out for: make sure your computer’s heat vents are pointing up/out of the bag, or it might overheat. With modern processors, this usually means it just shuts down without warning or saving anything, but it’s best not to let it get to this stage in case it leads to damage/deterioration.

Don’t come crying to me if your bag catches fire, either.

Makerbot #147 Online

In other news, on the same day I got my makerbot working after ages building and troubleshooting it! I had some great help from the good folk of the makerbot google group.

First thing was to troubleshoot the settings for the Plastruder. Here, it's making a raft successfully, though it later failed on the infill for the model because the heat setting was too low.

First build was a standard 608 Pulley, the same model used to make the pulleys that ship with the machine itself. They’re a good test, a simple model, and convenient to have as spares in case yours somehow break. If the shipping of 30+ pulleys works out favourably for you, the Makerbot crew are even offering $1 per pulley printed for them, because they’re having trouble producing enough for their kits! Very cool idea.

Left: Freshly printed pulley. Right, the one that shipped with the 'bot.

As expected, once the machine was online I had a few little teething issues that largely were due to software issues.

My initial problem (which was a long hangup) was with the ceramic insulator you’re supposed to put around the barrel of the extruder. Turns out it can allow the plastic to melt way too much, such that it blocks the plastruder. Your extruder cog-drive then chews a notch in the filament and can’t push it further, so the whole thing effectively stops. Removing the ceramic fixed the problem.

The next problem was with the temperatures being too low when the machine tried to fill in the layers of a model, so a similar build failure would occur halfway into the first layer. Some settings fixed in skeinforge solved this; all your temperatures should be at least the melting temperature of the plastic.

Finally, although the ceramic wrap caused much grief, its absence means the machine is highly unreliable near draughts or gusts of cold air. The barrel can cool below the melting temperature pretty quickly, and you get a build fail.

With those problems solved, I’ve so far printed two pulleys, a mis-sized beltclip of my design, and half of a belt-clip insert for hanging pippettes from one’s belt through said belt-clip. I am proud of my geeky weekender. Much was achieved!

My only hangup; someone with knowledge of Python would be much loved if they would rewrite Skeinforge to have a more self-explanatory interface. I mean, the barebones box-and-button interface is fine; what the hell do all those settings mean? Many thanks nonetheless to the Reprap crew for making the tool. It’s evil, but very useful.