Vlad's Gadgets

Gadget Diary – Digital TV for my Grandparents

I visit my grandparents regularly on Sundays. They are almost 90 years old and live in North Bondi.

A while ago, I bought them the Economy Digital Set Top box, which Jaycar Electronics sells for $29.95, so they could watch the new DVB-T digital channels on their old LG Flatscreen TV (purchased in 1999, but still in good shape). Unfortunately, they struggled to use it for the following reasons:

1. Their LG TV has several AV inputs, but unfortunately, when you power cycle the TV, it always goes back to the analogue TV mode. They subscribe to Russian language Satellite TV, and the descrambler was already connected to AV1, so I had to connect the set top box to AV2. The procedure of pressing the input select button twice to switch to AV2 was very confusing for them.

2. Furthermore, although the Digital STB reception was fine for most channels, they could not get any digital reception for ABC TV. Their analogue reception for ABC was bad, but still watchable. As you know, digital TV does not gracefully degrade in bad signal conditions – it is “All or Nothing”. This means that they would have to switch to analogue for ABC, and switch back to digital to get the remainder in top quality. It was also confusing for them to understand why there were multiple version of the same channels (the analogue version and the digital version).

3. The remote control for the Economy STB is quite tiny, and if you don’t release the channel up or channel down buttons fast enough, it will repeat the command and skip over a few channels. Not a problem with my nimble fingers, but difficult for them.

My Solution

I tried giving them a programmable remote control, but this did not help. They were confused by the plethora of buttons. They kept pressing the wrong one, and putting the remote into the wrong mode. As a result, they seldom watched channels on the Digital Set Top Box. It was frustrating for me to see them struggle to do something that I thought was intuitive, but I vowed not to give up to help them.

After analysing the situation, I understood that their struggle was state-based decision making. They struggle when the required sequence of button presses depends on the current state of the TV, i.e. whether the TV is on or in standby mode, whether it is listening to the AV1 input of the old analogue channels. They need the simplest possible procedure that is state independent, i.e. combinatorial logic.

I knew I could solve problem 3 by lending them my spare Teac SDB452 SD Set Top Box with PVR. It has a larger remote with bigger buttons, and when you press the channel up and channel down buttons, it only sends the command once, even if you hold down the button. To my amazement, this set top box was able to receive ABC TV almost perfectly (every now and then, there are some noise artifacts, but it is still watchable). This solved problem 2 – they would now have no reason to watch Analogue TV, which will be shut down by 2013 anyway.

The only problem now was problem 1. The only easy solution was to reconnect the composite outputs of the Digital STB to an RF modulator, to allow it to be accessed as an analogue TV channel on the LG TV. I would never ever do this for myself, as the modulation processes reduces the image quality a bit, but it wouldn’t make any real difference to them. I programmed it so channel 6 on the LG TV was tuned to the RF modulated signal from the Teac STB. As a result – when they turn on their TV, it will default to the last analogue channel that they were on, which will almost always be channel 6. All their Australian channel selections will be made using the Teac SDB-452 remote.

This was the final outcome:

• To watch Russian TV, all they do is press the AV input select button on their main LG remote, and then use the remote for the Russian Satellite descrambler to select the Russian channel
• To watch Digital TV, all they do it press the channel 6 button on their main LG remote, and then use the remote for the Teac STB to select the Digital TV channel
• If they power cycle the TV, it will go back to channel 6, so it will respond to the Teac STB remote automatically. There should never be a reason to change the analogue channel on the TV from 6.