Charge Only MicroUSB Cable

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I’ve been using either Verizon, Sprint, or AT&T’s mobile broadband service for over five years. I’m now on my fourth technology iteration and I have a hard time remembering what it was like when Internet was only available at home, office, and the café. I refuse to return to those dark ages!

Until recently I used Verizon’s first generation of MiFi hotspot, the Novatel 2200. It’s a great little device that did exactly what I wanted it to. When I needed it to be a WiFi hotspot, it was a hotspot. When I was on the road and needed to charge it via my laptop’s USB port, that worked perfectly as well. Recently however, my company upgraded me to the newest MiFi hotspot, the Novatel 4510L. For the most part the new device is faster, shinier, has better reception… it goes to eleven!

The problem is, and I consider this to be a design flaw, is that when you plug the device into a PC, with the USB cable provided, it will only charge the device. The 4510 will neither operate as a WiFi hotspot, nor will it operate as a USB connected modem. I learned this the hard way last week when I spent most of the day at the green mermaid coffee shop waiting for the mechanic to finish my car repairs. As it was a crowded day in laptop land, I only managed to get access to a single power outlet. When the batteries on my MiFi hotspot were nearly tapped, I had to resort to swapping between the laptop charger and the MiFi charger every hour to make it to my car pickup.

Armed with a soldering iron and heat shrink tubing, this was an easy hack. A USB cable has four wires; two for power, two for signal. If you cut open the cable and clip the signal wires, then you effectively create a charging cable. Based on a support forum thread at Verizon Wireless (http://bit.ly/pBqf1h), I also learned that you can trick the 4510L into thinking it’s attached to its AC charger if you additionally short the signal wires on the MicroUSB side. So, I closed the circuit on the green & white signal wires on the MicroUSB end of the cable. Important: The signal wires on the host or USB A end of the connection must remain open or you risk shorting out your USB port or damaging your computer.

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Typical USB cable color coding: Red +5v, Black, GND, White Signal+, Green Signal-

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Tie the power wires together, solder & insulate. In order to trick the Novatel 4510L into thinking it’s connected to its AC adapter, short the signal leads on the device or MicroUSB end. Be sure to leave the signal wires on the host end of the cable open. Insulate all of the wires with electrical tape or heat shrink.

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Finished product. I only made the cable 6″ long so as not to add to the rats nest of cables that I already keep in my backpack.

[Update 2011-08-16 10:06 PDT]: According to Verizon Wireless, the shortcoming of not being able to charge and operate the Novatel 4510L while plugged into a PC USB port is a design constraint and not a design flaw. Many PC USB ports fall short of the 500mA power spec and do not provide enough energy to both charge the batteries and power the MiFi radios. My MacBook Pro happens to have enough juice (http://bit.ly/niXKgJ), so I feel it is safe to operate with my hacked cable. You may want to check the specs on your laptop’s USB ports before you proceed.

T1 A/B Switch – Arduino Rocks!

The Problem

TAG T1 AB Switch

In our organization, we have an Asterisk based phone system. Because we are a 24X7 365 operation, and because our business must react quickly to customer demands, we actually have a completely redundant Asterisk system idling in standby mode. When we have to transfer over to the redundant system most of the operation takes only seconds, with one exception. Some of our inbound and outbound call traffic is carried over old school, plain ol’ telephone service (POTS) via physical T1 data circuits. In order to move these T1 circuits to the failover server, one of our engineers had to physically move the patch cables from one server to another.

Our engineers have tried a number of failover options, including converting the T1s into VoIP traffic so we could just change the packet routing when we needed to swing the calls to the failover system. However, the hardware and the software we’ve found, so far, does not meet our quality of service needs.

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Security Camera Ceiling Mount

Hanging security camera mount

One of our network engineers came to me with a problem. A security camera in one of our warehouses had been knocked down and the mount destroyed. The manufacturer doesn’t make the mounts any more, so we came up with a DIY solution to remount the camera from the ceiling with full swivel and tilt capability. Currently pictured upside down and with a spare point and shoot camera. When installed, the actual video camera will hang from the ceiling.

[slickr-flickr search=sets set=72157625480172239]

Making Your MagSafe MacBook Road Trip Worthy

I have joined in with a chorus of geeks who wish they could use and recharge their MacBooks while they were in the car or boat. But Apple only makes a DC adapter that is compatible with airplane power ports and not with 12V car (cigarette lighter) ports. Since the MagSafe connector is patented, and they have yet to license it to third parties, there just aren’t any commercial solutions to-date. Sure you could use a power inverter to plug your normal power brick in to your car, but the conversion from DC to AC and then back to DC is extremely inefficient, and I’ve found most devices to be rather noisy and hot. I was looking for a DC-DC conversion solution, and I figured I would have to take matters into my own hands.

MagSafe Pinouts

I am a decent maker/hacker and I love playing with electricity. I can’t tell you how many times I’ve electrocuted myself in this lifetime… all in the name of science and discovery of course. Nevertheless, I am out of practice, and when I looked at the four or five pins at the end of of the MagSafe adapter, I assumed that there was some complexity to the voltage and polarity, and I had neither the time, nor the drive to figure it out. Plus, my MacBook Pro is now my primary business asset. If I mess it up by shorting it out somehow, this experiment gets very expensive very quickly. So, I put this project on the bottom of my to-do list as I waited for something better to come along.

About a week ago, I came across this link (via RubyHead) to Mike (MikeGyver) Lee’s website where he sells both turn-key solutions as well as instructions to build your own DC-DC power adapter for the MacBook and the MacBook Pro. The great thing is that I already owned one of the third party power adapters that he recommends, so all I needed was about $7.00 worth of radio shack parts. Awesome! So, I bought the do-it-yourself instructions from Mike Lee, and gave it a go last night. So far it works great!

MacbookProCarAdapter

It turns out that the polarity and the pinouts on the MagSafe Adapter are really no big deal. I won’t give away the details in this post. So if you are interested in doing it yourself, or even buying a turn-key solution, please check out Mike Lee‘s information. I advise you to visit this site sooner rather than later as Apple has away of making cool and helpful things like this disappear through cease and desist orders. Anyway, I now have a road-trip worthy MacBook Pro.

[UPDATE: 2007-06-25 10:30 AM PST]

Yes, this configuration does charge the MacBook’s battery, unlike the Apple Airline adapter which just powers the laptop. It’s hard to see, but the indicator light on the MagSafe plug in the picture above is indeed orange.

Programable Status Board

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UPDATE: Please see this safety recall for important information on some of the components related to this project!

In September, I read a post on one of my favorite blogs about these Triklits programmable LED light strings and I instantly fell in love with them. I ordered two strands as well as the USB interface card and had a ball making these things come to life. After fiddling with them for a couple of weeks, I began to build this automated statusboard to help me monitor systems for me and my clients.

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