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Electronics

TAM horror

My FRITZ!Box has been getting empty answering machine messages! One every 45 minutes. It turns out that Telstra has a potentially useful service that delivers SMS messages as voice messages. Unfortunately, figuring the service out is less easy. Read More...

Tronixlabs LCD Backpack

For my Raspberry Pi GPS NTP server project I found it useful to have a display available to put up simple status messages for example the IP address and the output of ntpq.

To that end I purchased a Serial I2C backpack for HD44780-compatible LCD modules from Tronixlabs. Although they provide a tutorial for the use of these devices I had greater success with a different Python library. Read More...

Tronixlabs DS321 hardware clock config for Rasperberry Pi

For various reasons I need to make a Raspberry Pi into an NTP time server and for this to work I need time to be roughly right when it starts. hence we need to add an RTC to the Raspberry Pi running Raspberian.



Tronixlabs supplies a very nice module (http://tronixlabs.com/raspberry-pi/real-time-clock/ds321-real-time-clock-module-for-raspberry-pi/) but the instructions are a little less than optimal.


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Do not use a cannon to kill a mosquito

Some time ago I installed a series of IP cameras to keep an eye on the horses at the farm. With the dodgy power, the sometimes less than stellar performance of the IP link to the farm (it is a long radio link) and the generally poor firmware found on domestic IP cameras, it is not a rare event that that the cameras lock up and need a power cycle.

My original plan for fixing the issue was to install an Arduino with an Ethernet driving a relay and have a Nagios event handler tell the Arduino to bounce the relay. I already use something like this to help fix the WiMAX radio link when it gets confused. Reducing the number of calls I make to my saintly mother-in-law and brother-in-law to help bring the link back up.

After a face-palm moment I realised I was over engineering this problem and already had a piece of equipment that gave 90% of the solution - a ToughSwitch POE. This PoE switch has a watchdog facility that reboots devices if they fail to ping for a sufficiently long period of time - I deployed this device to control my outdoor APs in November of 2013 to great success. All that was needed was to make the cameras PoE devices ...
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G-Code: A poorly define language

Many Computer Controlled Machines used for CNC use NC-code / RS-274D / G-Code / Gerber to describe their programs. This language appears to be very loosely defined. To save others searching I am summarising some sources and observations about this language. Read More...

PCB Routing

I recently acquired a Roland iModela iM-01 which I intend to use for routing small PCBs. This is the first of a series of articles about getting to a working toolchain. There is a bit of a learning curve with using CNC and many of the tools only exist for Windows. One of the things I wanted was a tool path tracer - so I could quickly see what the NC-code / RS-274D / G-Code does. Read More...

Do you have Foxtel ...

The power saving power board people have been around … yet another piece of equipment fails due to their poor training.

There is an Australian government program which allows electricity users to receive standby power saving power boards in exchange for the carbon credits the devices are estimated to deliver. Unfortunately, the training given to the people who deliver the boards is poor. The only question they appear to ask is “Is that device for Foxtel?”, and that is the only device they plug in to an outlet that stays on all the time. Read More...

DFRobot Xhouse

DFRobot (www.dfrobot.com) have a demonstration iPhone App and software for their Xboard series of devices. Apart from a small issue with a cable the Xhouse demo project was a fun little diversion - easily built and potentially useful. Read More...

Low cost LeoStick based Serial Switch

The farm is connected to the Internet by a WiMax based wireless service which occasionally has a problem which needs the WiMax modem / router to be rebooted.

A low cost USB powered switch connected to one of the computers at the farm solved the problem nicely.

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Legacy FreeBSD serial IO with Freetronics Leostick

Freetronics (www.freetronics.com) builds an Arduino Leonardo compatible device called the Leostick (www.freetronics.com/collections/arduino/products/leostick) that plugs in to a USB port and provides a builtin serial, keyboard and mouse emulation. Unfortunately, versions of FreeBSD before 9.0 don’t recognise the serial port. A hacked version of the FreeBSD modem driver can be created to allow communication with the Leostick. Read More...

Legacy FreeBSD Eleven and Etherten Serial Support

Freetronics (www.freetronics.com) builds a range of Arduino compatible devices in particular the Etherten and the Eleven. FreeBSD’s (www.freebsd.org) does not natively support the serial interface of these devices. Fortunately the uarduno (mrp3.com/uarduno-1.02.tar.gz) port does and I am happy to report that this works on FreeBSD 5.4 and works at least with Etherten and probably with the Eleven with a trivial addition to its configuration file. Read More...

Contact sense in 24 Hours

Lots of quite expensive equipment used in telecommunications, television and security still use contact sens outputs for reporting error conditions.This project was put together in the space of 24 hours to allow Nagios to
monitor some contact closures.

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