TV Saver – Solving the TV Standby Problem
Galen Brown
Background – the Problem
An enormous amount of energy is wasted powering devices such as televisions, VCRs, DVD players, game consoles, digital t-top boxes, etc, while they have been left in a standby state. This wastage is incread by many of the devices only being able to be switched fully off at the socket. An average colour television may consume around 40 watts of electricity when fully on but will continue to draw 10 watts while on standby. For an average VCR this standby energy usage is even higher at around 15 watts. While many people do not fully switch off even their television when it is not in u, tho who do rarely switch off the associated devices such as DVD players and VCRs.
It is uful to refer to the combination of a television and all associated equipment as a home entertainment system (HES). The associated equipment may consist of a DVD player, VCR, game console, digital t-top box, signal amplifier and/or other equipment. Table 1 shows the standby energy usage of the author’s HES. Note that the figures given were found first by measuring the standby power of each device and then by referring to the technical specifications in the instructions for
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each device.
Device Standby Power (W)
Television 10
VCR 15
DVD player 8
腌酸辣萝卜Digital t-top box 7.5
Total 40.5
Table 1: Energy usage of a typical HES on standby
研学游作文Where most or all devices in an HES are left on standby all or most of the time, this results in a large amount of energy and money being wasted annually. Table 2 shows an estimate of this wastage. Note that the money calculations were bad on a price of 8.49p per unit (Scottish and Southern Electricity standard prices in March 2006). Since then electricity prices have continued to ri and as such the amount of money wasted will be higher than the values given in the table.
Device Time device is
switched on per day Energy wasted per
year (kWh)
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Television 3
hours 77 £6.54
VCR 1
hour 126 £10.70 DVD Player 1 hour 67 £5.69
Digital t-top box 3 hours 57 £4.84
Total ---------------------------
327 £27.77 Table 2: Estimate of money and energy wasted through devices left on standby
As many houholds own more than one HES, and certainly more than one television, the energy usage and price is multiplied by the number of HESs in the houhold. The energy wasted nationally (with the associated environmental damage) by devices being left on standby has recently been widely emphasid.
The Solution
The TV Saver was created to address the problem of televisions and associated devices being left on standby by switching off a television and all associated devices when the television had been
left on standby for a number of minutes.
The design specification specified that the TV Saver must not create an inconvenience for the ur. As such it must have a means to switch all the devices back on again when required, with no
more effort required from the ur than would be if a remote control were ud to switch on a television from standby. The television must ‘continue to be operable solely from a sofa’!
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Also specified was the need for the ur to have a method to override the TV Saver, so that when the television was switched onto standby the devices would not all be switched off. This was important as all devices, including the television, are switched on and off together, and the ur may wish to record using a VCR or DVD recorder without the television switched on.
Two main approaches to solving the design problem were developed. Both involved creating a multi-way extension lead connected to a controlling box and making u of a latching relay to switch on and off all the sockets of the extension lead. Both approaches ud programmable microcontrollers, although the were programmed in different ways to reflect the different approaches. Different circuitry was also required for the different approaches. The difficulty then lay in how to determine when the HES could be safely switched off without either damaging the equipment or inconveniencing the ur, and also when the HES must be switched back on again. The first approach involved programming the microcontroller to learn and store the digital infrared signal emitted from the television remote control’s on/off button. The TV Saver then recognid this signal whenever it was received in future. On receiving the signal it responded by switching on or off the HES depending on its current state.
However, there was a major problem with the first approach. There would always be the possibility t
hat the television would receive and respond to the signal, but that the TV Saver would not (for example, if the signal was blocked by an obstacle in front of the controlling box). This would place the television and the rest of the HES out of synchrony with the TV Saver and would therefore need to be ret, causing an inconvenience to the ur and violating the design specification. The cond approach solved this problem and has been adopted as the preferred solution.
The Selected Approach
The lected approach works by measuring the power usage of the television instead of relying on storing and recognising the television remote control’s on/off signal. Therefore, when the television goes onto standby, the TV Saver ns the reduced power usage of the television. When the television has remained on standby for a short time (currently t at five minutes) the TV Saver switches off the HES. The time delay is necessary to allow the ur to continue to operate the other devices in the HES after the television is switched off (for example, to rewind and eject a video). If the TV Saver receives any infrared remote control signal (e below) during this time delay, this is interpreted as continued u of the HES and the timer rets itlf.
In this method the TV Saver contains an infrared receiver, and the microcontroller is also programme
d to switch on the HES on receiving a signal from any remote control. The television then comes onto standby and since the ur is still holding down the on/off button on the remote control the television comes fully on. The additional time for which the ur must hold down the button is no more than one cond, so there is no long delay between the television coming onto standby and switching fully on.
When this approach was initially tested, the TV Saver unexpectedly switched on
the sockets to the HES every few minutes. This was found to be caud by fal
output signals from the infrared receiver. To solve this problem, the microcontroller
program was modified such that veral puls must be received from the infrared
receiver in a t period of time before the TV Saver turns on the HES.
The TV Saver has been designed and built with two override buttons – ‘Temporary’ and
‘Permanent’ – and a ven-gment display in the controlling box (e photos). Both override buttons prevent the TV Saver from switching off the sockets to the HES even when the TV is on stan
dby. This feature was specified in the design specification to enable the ur to record a television programme whilst the television is not fully on. The microcontroller has been programmed so that the TV Saver may be overridden for up to nine hours, with the remaining number of hours displayed on the ven-gment display. The override is t by holding down the
‘Temporary Override’ button until the required number of hours is shown on the display. The
‘Permanent Override’ button allows the ur to override the TV Saver indefinitely, with a flashing alert to stop the ur inadvertently leaving it in this state.
The TV Saver also features a ‘Turn On’ button in the controlling box, which switches on the power supply to the HES, causing all the devices to come onto standby. It does not, however, either switch the television fully on or override the normal operation of the TV Saver, so if the television is not then switched fully on within five minutes the TV Saver will again switch off the sockets to the HES. It is included for times when the ur cannot locate the television remote control!
To continue to operate, the TV Saver must receive a continuous supply of electricity from the mains even when the HES is switched off. However, this power requirement never ris above 0.5 watts. The TV Saver contains a built-in linear power supply to provide this energy.
Future Developments
Future developments may include providing the TV Saver with a switched-mode power supply. The are more efficient than linear power supplies and would further reduce the TV Saver’s power consumption. At prent this is impractical due to the extra cost and complexity of a switched-mode power supply weighed against the tiny difference it would make to the average ur’s energy usage and electricity bill. Using a switched mode power supply may only reduce a ur’s electricity bill by a further 60p per year when compared to the current TV Saver with a linear power supply. The extra manufacturing cost is likely to make this development not worth pursuing.
A more likely and simpler development is to provide the TV Saver with passive power factor correction. Although this would not affect the amount of power that the TV Saver us and would not affect the ur’s electricity bill, it may become necessary in future due to regulations concerning domestic electronic devices. Adding power factor correction may also be en as environmentally friendly, as electronic devices with a low (bad) power factor increa energy loss in power transmission lines. However, as the power consumption of the TV Saver is very low, a low power factor will not create a big problem.
A further future development, already in progress, is to modify the microcontroller program such that it also has the ability to learn the digital signal emitted from a television remote control’s on/off button, integrating technology developed for the first approach. If the ur enabled this feature, the TV Saver would only switch on the sockets to the HES on receiving this ur-programmed signal, rather than on receiving any remote control signal. This would be an advantage if a device (such as a CD player) in the same room was controlled by an infrared remote control but not plugged in to the TV Saver. Without the added functionality of the TV Saver, the HES could be switched on unnecessarily by the ur operating the remote control of the other device. The ur must be able to lect this as an optional feature, as they may prefer the simplicity of the original design. In this ca the ur need not program a remote control signal into the TV Saver, which will operate as normal with all remote control signals. This development is a software-only modification, i.e.; it involves modifying only the microcontroller program and not the electronics of the TV Saver.
Skills and Knowledge Acquired
In order to create the TV Saver I had to develop many new skills. The included:
• Electronic prototyping
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•Improving basic skills learnt from school in microcontroller programming (including teaching mylf Asmbler from internet resources)
•Power measurement methods (from internet resources)
•Power supply design (from internet resources)
•Infrared remote control communications (from internet resources)
• Soldering
•Printed circuit board production (from internet resources)
•3D CAD for final design of casings (from professional advice locally)
•Applying all of the above in a safe way.
Component Sourcing
Some of the components required for the TV Saver were common and could be purchad online from electronic retailers such as Maplin Electronics. However, others components were highly specif
ic, which initially created a design constraint. Eventually, more detailed arching located other suppliers: in one ca a component had to be ordered directly from the factory in Thailand.
Building and Testing Prototypes
I aimed to build four working prototypes to allow for distribution for testing and demonstration. The printed circuit boards were manufactured using a simple manufacturing process similar to the industrial process (e photos showing printed circuit board construction). They were then fitted into boxes, which the circuit boards had been designed to fit. The multi-way extension leads were adapted from existing ones, which is fine for the purpo of prototyping but clearly needs a specific design before taking the TV Saver to market. Once constructed, the TV Savers all worked and met all design specifications. I have also developed a full t of ur instructions, which are attached. One of the prototypes has been in u at home for the last four months (to November 2006) with no problems. It has even survived independent u by my two younger sisters (12 and 6) who find it easy to u. I have also given one with a full t of instructions to my project mentor, James Clouston, and have lent them to other school pupils to test, all of whom have reported that it worked well. It has also been tested on other televisions and found to work fine.
Patent Application and Further Development
I have applied for a patent (application number 0610222.2) for the TV Saver using family funds and have recently had results of the first arch from the Patent Office. There were some superficially similar patents, which were different in detail to the TV Saver. The next stage is to address the similarities identified in the first arch, but this requires additional finance.
In summer 2006, once the patent application had been submitted, I contacted veral large retail companies including B&Q, DSG and Maplin Electronics regarding further development of the TV Saver, but I received no respon from them. I also contacted the Energy Saving Trust who indicated that they would be very likely to endor the TV Saver if I could get it tested for electrical safety. However electrical safety testing is not only expensive, but can only be performed on the final design of the TV Saver and not on a prototype.
The final design of the TV Saver would be contained in a specifically moulded plastic box rather an existing one purchad off the shelf. I am envisaging constructing the final design of the plastic box using rapid prototyping, followed by larger scale production using plastic moulds. However, rapid prototyping and creating plastic moulds are very expensive and would require funding.
I have recently contacted Trevor Baylis Brands plc for advice regarding taking the TV Saver forward,
who replied with an offer of free initial rvice in return for a one-third share of the product. The next steps in bringing the TV Saver to market are:
•Get an estimate for production cost bad on an estimated retail price of £35.
•Find funding – I am planning to approach Highlands and Islands Innovation Centre for advice. •Address results of patent application’s first arch.
• Finali casing design.
•Produce a small batch for electrical safety testing and for testing the market.
•Get the Energy Saving Trust to endor the TV Saver.
• Develop website.
•Find retailers prepared to ll a test run.
•Manufacture test run (around 2000) including packaging: probably in China, via local contacts. •Market the TV Saver.
•Rai extra funding for next larger batch.
