Monthly Archives: February 2014

Saving energy on the small things

There are fundamental two ways to be “green” in regards to electricity; either reduce the demands on the planet to produce it, or use less. Examples of both can be found in some households. Solar panels can reduce the amount of CO2 produced to get the energy, while energy efficient lightning reduces the demand.

In recent years many countries have placed limits on how much energy a device can use to do a specific job, for example a fridge. This is implemented via the MEPS(Minimum Energy Performance Standards) directive. Currently the MEPS directive is focused on a select group of large power hungry devices. Although Im sure this will be expanded there will always be a limit as are simply too many devices. There are also new types of devices popping up all the time. There will therefore always be “gaps”. It is these “gaps” in the regulations that I am particularity interested in here.

I thought it would be good to try to find away to push all devices to be more energy efficient; but how can that be achieved? Well its fair to say that independently assessing every new product would never work in the real world, the overhead in cost and time would be enormous. Though it may be possible to target specific aspects in the device which can be found in every product. One of these is the power supply. This can be a very large source of wasted energy in a product.

Its critical to note at this stage that making an energy efficient power supply is not always the most cost effective at low voltages. A typically inefficient linear regulator often costs less to make than a higher efficiency switching power supply; however in some situations a linear power supply can actually be more efficient. In some cases it is undesirable, or impossible, to use a switch mode power supply as it can generate more electronic noise (EMI). It is also worth noting that a switch mode power supply typically physically weighs more and takes up more space in a low voltage electronics design. Therefore the energy costs to build and transport it are more. In a nutshell unlike light-bulbs, you can’t just ban a particular item.

So how would this work then? Well as implied there are three aspects to consider.

1) The actual efficiency of power supply.

2) The amount of energy needed to make it

3) The amount of energy to transport it.

Their are already existing pressures to reduce the energy needed to make and transport a product, as a larger heavier items cost more to post and use up more material which also has a cost associated with it.

For the efficiency: Consider a product uses a linear power supply to power its electronics at 3.3V from a 9V battery. The efficiency of this power supply is 3.3V/9V = 36.6% efficient. If instead a switching power supply is used the efficiency might be as good as 90%. It is worth considering that many battery powered devices will themselves have a desire to increase, “battery life”, though this would not be the case for all of course is not a factor when considering mains powered devices.

Therefore if a small tax is added that is inversely proportional to the efficiency of the power supply then there would be a driving force at the design stage, making efficient powers supplies cheaper than inefficient ones. If a product absolutely needs an inefficient power supply, which can happen, then it pays the cost penalty. This hypothetical tax should not be set to high as it must not negate the energy costs manufacturing and shipping the product and in should therefore be optimized so that for the average product the cheapest way is the way that uses the least amount of energy.

 


Rat control and predator free islands

Rats can be an ecological nightmare, in a predator free enviorment a single pregnant female rat could cause chaos and if we are very unlucky, the extinction of a species that is unable to compete with them.

The concept of the predator free island was started on New Zealand, were vunrable birds are relocated to small islands that have been eradicated of rats and other preditors. This has been a very successful and Im personally really taken back by how easy many experts make these seemingly impossible goals a reality.

Of course after the eradication there needs to be very strict controls to ensure alien species don’t get introduced as well as regular monitoring to ensure there are no univited guests.

This of course takes time and in a nutshell money. Not only that but you can’t have people everywhere all the time. I wondered if there is a piece of technology that could assist with this task.

I came up with the concept of a weight activated rat detector. I’ve had quite a look and simply can’t find it anywhere.

So why would this be helpful? Well as a general rule many alien rat species(e.g. The brown rat) are heavier than the local rodents. Therefore the heavy, and mature, rats will trigger it, while the native rats are left alone. Having the rat trap a more targetted killer means that leaving it in place for a long period of time wont decrease the native rodent population. As a side note this means of course that potentially this technology could actually be used for the eradication as well, especially in situations were another rodent is critical endangered.

So how would it work? Well there really are a number of ways they could work. They could simply be based on a mechanical design in which a certain amount of force needs to be pressed onto the floor to trigger a switch. Or they could be electronic were the weight is measured and if its above a certain limit the rat get zapped.

However this being said there is an interesting point to consider. The weight activated trap won’t kill lighter(younger) rats. Therefore for this to be effective there does need to be a significant average weight different between target and native species.


Speeding and the three second rule

Like so many people, I nearly had someone crash into the side of me as they changed lanes. I’m pleased to say that I braked just the right amount so to avoid being hit by this car; I’m also pleased to say that I also avoiding the person behind me rear ending me, phew!

This however got me thinking about how my experience and similar ones could be avoided. My first reaction was about the car and the driver that nearly hit me, but at the end of the day at some point everyone will make a bad judgement on the roads and will have a near miss; its going to happen. I then began to think how much easier my situation would have been if the car behind me wasn’t so close.

I checked and there are laws, with penalties, to ensure that cars need to be a certain distance apart; however as far as I’m aware there is no electronic deterrent stopping people driving bumper to bumper. This is of course unlike speeding.

Certainly from my own experience people are far more likely to drive bumper to bumper then speed past a cop car. I think that few would disagree that the reason behind this is you are far less likely to get charged for it. I believe one factor in this is that it is hard to prove this is the case without an electronic record. Though for completeness there will be a video record in the cop car, but to my knowledge no system to alert an officer of a breach.

The question is, does this have to be the case? Could current technology be adapted, or built on, to deliver a combined solution(speeding and detecting distance) to help with road safety?

Fundamentally all a device needs to do is measure the time between one motor vehicle and the next. If its to short a time for the given speed then it can alert the user, hence of course the term the “3 second rule”.

As far as I can see there are two fields of technology that could potential be built on to deliver this. The most restrictive, and I would envisage simplest, is using RF “toll” road tags. Key factors that would have to be looked at is the RF pickup range(false pickup from another lane) and the response time, though I would think such a system is possible.

This however is restrictive as it only works if the offending vehicle in-front both have an RF device installed…

The other field is of course vision system, in particular ANPR(Automatic Number Plate Recognition) system. Though no vision processing is a trivial task, the journey from nothing to our current system is very much larger than from where we are with some additional inter-plate timing additions.