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Letters and emails should contain complete name, address and daytime phone number. Letters to the Editor are submitted on the condition that Silicon Chip Publications Pty Ltd may edit and has the right to reproduce in electronic form and communicate these letters. This also applies to submissions to "Ask SILICON CHIP" and "Circuit Notebook".

Audio delay for
sports commentary

As the cricket season is upon us I find myself turning down the volume on the TV and tuning in the radio to the ABC. I then run this signal through the following software to get the two in sync: http://www.daansystems.com/radiodelay/

Looking at your DAB+ radio project, it struck me that there is plenty of room in the case to fit a hardware version of the above software. The most delay I have ever had to apply is 4.5 seconds so not a lot of RAM would be required and it should be within the processing power of the current range of PICs. Or how about a standalone version?

Rob Chandler,
Clayton North, Vic.

Comment: thanks for the suggestion. In fact, because DAB+ radios buffer the digital signal, they can produce a significant delay and it varies from model to model. We checked out our own DAB+ tuner and found the audio delay to be close to 10 seconds.

By the way, if you like to participate in radio phone-in competitions, that order of delay will put you out of the running.

Analog audio outputs
for large flat screen TVs

I have been belatedly reading the July 2010 issue which contained both the Publisher’s Letter and a Mailbag letter lamenting the lack of analog audio outputs on flat-panel TVs. We purchased a base model Sony Bravia LCD TV in May 2010 and this does have analog outputs.

This was a consideration in deciding which set we purchased. Although we initially tested the analog outputs via our early 1990s vintage 2.0 channel surround sound system (aka stereo amplifier and speakers), the sound quality from the TV’s speakers is surprisingly good so we did not persist in using the external sound system.

Another point mentioned in the Mailbag letter is that the TV remote can’t usually control the volume when using an external sound system. Fortunately, the Sony TV is not subject to this problem as the analog outputs can be configured to either be at constant level or variable level; ie, they still respond to the TV’s volume and mute controls. Another way around this problem is to use a programmable remote control – we have a Logitech 525 – and remap the volume and mute buttons normally used for the TV to send the corresponding IR codes which suit the external sound system.

While the Logitech software does not allow IR codes to be cut and pasted between various devices, it is possible to use the “learning” feature to add specific commands for other devices to a target device, using the original remote; eg, in this case the remote for the sound system. The original IR codes for the TV volume and mute can be allocated to other buttons on the remote, so they can still be accessed if needed. The Logitech 525 remote has provision for several “pages” of commands to be allocated to the upper LCD section of the remote, which caters for four commands per “page” with corresponding buttons, so this is a good place for lesser-used commands.

Also see for setting up a Logitech remote to control a Mac Mini home-theatre PC.

Richard Stallard,
Nedlands WA.

Ideas for
recycling

I was wondering what happened to the recycling section of your magazine. I though that it might be because of a lack of ideas, so I have included some in this letter. I have used the LED strip light out of an old fax machine for a night light now for a few years. I reconfigured it to work on 5V and powered it from an old mobile phone 5V regulated plugpack.

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