Fast satellite

Posted May 27, 2015 by rcaron
Categories: Uncategorized



Kerbal 8km/s

Posted May 25, 2015 by rcaron
Categories: Uncategorized


Kerbal aviation

Posted May 18, 2015 by rcaron
Categories: Uncategorized


Suborbital with Kerbal

Posted May 12, 2015 by rcaron
Categories: Uncategorized


RT-N16 Tomato, with site-to-site VPN

Posted April 4, 2014 by rcaron
Categories: Linux, router

Tomato & RT-N16

I’ve been using the Shibby fork of TomatoUSB everywhere (1x E3000, 1x RT-N66U, 3x RT-N16). In particular, tomato-K26USB-MIPSR2-116-AIO. To install it on the N16 I initially flashed a smaller, initial load of dd-wrt (trx), as the Asus firmware seemed to have an issue with the large 6MB firmware (the initial dd-wrt was ~3.5MB).

In dd-wrt, I selected the tomato trx file and had it set to factory defaults after restart. For some reason I had to use a “Private Window” in firefox (Ubuntu 12.04LTS, FF 9000) for the tomato firmware to take. Otherwise I would just see dd-wrt’s “Upgrading firmware, please wait 300s” for about 2 seconds before I got a 404 error.

Once booted into tomato I had it do a thorough NVRAM clean out again. Just be to be sure.

The multiple images were kind of a pain, but allowed me to skip having a TFTP server (or using the Asus Recovery Utility)

I like the RT-N16 since it is a workhorse while still being under $100. These locations are mostly Ethernet based anyway, with little need for 5 GHz. capability.



Right now I have three of these going with a site-to-site transport VPN (1 server, 2 clients) to have a common network with DHCP, and a Windows Domain, on top of the building network which does not have such services.

The site-to-site OpenVPN instructions have vanished but I got them through the only issue is you can’t view the images, only the thumbnails, which is problematic. Good thing I already had one of these set up! I’ve emailed Wasaga Computers to hopefully get this guide back; if not I’ll recreate it here since it is so useful

I used my Ubuntu 12.04.3 LTS environment to make the OpenVPN keys. The working directory is /usr/share/doc/openvpn/examples/easy-rsa/2.0/ and I had to build the keys as root.

The key generation instructions are at

Home power monitoring

Posted June 30, 2012 by rcaron
Categories: Power

I think power management, a big aspect of my design work, has trickled into to the apartment. Management of course has two key aspects – monitoring and control. I will list my tools for the former below, the later will be another post.


Kill-a-Watt meter
The P4400 meter to monitor usage, but it is really only intended for a specific device or power strip. It also doesn’t provide any logging or record-keeping, so it is really intended to be intermittently used or spot checked, and is best used for devices that are a constant mode, or perhaps a couple of modes. I’m using it to put together a spreadsheet of loads, one room at a time.


EM100B Black & Decker monitor
This is a two-piece wireless setup with a photodiode looking at the spinning wheel on the power meter outside and transmits that information to a base station on 433MHz. The station then performs some math, using the Kh factor printed on the meter, to get the kilowatts used for the entire apartment. This in then tallied, and multiplied by a user-input cost factor to get the price utilized. It also happens to record the temperature.

My biggest problems are twofold – first, there are no provisions for more elaborate computer based logging, though there are some promising hacks. Second is the reliability of the photodiode, or more particularly the mounting equipment, to keep everything aligned. If it slips, or gets bumped, the meter zeros out. I put a few dabs of hot glue on the assembly today that hopefully should improve things.


Kill-a-watt wireless
The P4200 and P4220 are a simple extension of the original kill-a-watt so that usage can be conveniently displayed (not stuck to an outlet at floor level or jumpered on an extension cord). It also provides some logging and cost calculations (but no computer interface either). It runs on 916MHz and would be great for large but variable loads (air conditioners, entertainment center, refrigerator etc). Also one base station can manage up to 8 outlets. Unfortunately, the range is awful. One meter may work, 1.5m doesn’t. I will have to sleuth around for radio interference before I purchase additional outlets. The funcube dongle will be a handy tool for this.


Efergy E2 wireless monitor
This is another whole-house monitor, in principal like the black & decker one above. However, it measures by clamping onto the mains that enter the circuit breaker, as opposed to an optical sensor on the meter. This is really more appropriate than homes than apartments, so I purchased one for my parents to try out.

New callsign

Posted April 5, 2012 by rcaron
Categories: Amateur Radio

I have received the callsign NX1U (and thus released KB1LKI).


I’ve always wanted a N prefix, and I had to keep the 1 designator of home. The rest was just looking at the availability list and finding one that looks right. Admittedly it isn’t the best callsign for contesting in either phone or voice, but it sure beats my old 2×3!