How Does Our Text Messaging Device Work?

April 9, 2014

Overview

A text messaging device allows you to receive SMS alerts to any mobile phone whenever one of the inputs is grounded momentarily. You can also switch something on by sending the device an appropriate command.

The popular model we supply connects to our base receiver has two ‘zone inputs’ so that whenever one beam-set is triggered you will receive a customised SMS message like: ‘Gate 1’ / ‘Gate 2’ or whatever you like.

The unit has a GSM ‘engine’ inside, the same as you would find inside any mobile phone, except there is no keypad, screen or microphone etc. Its sole purpose is sending pre-determined SMS messages to pre-determined recipient phone numbers whenever something triggers the alert. It may also be used for controlling something from your phone.

A pre-pay or on account SIM card is first purchased from Telstra (Australia) or Vodafone then activated and inserted into the devices SIM card holder. The unit is then programmed by serial interface with a suitable PC. We usually program the device for you and test it to your phone before it leaves our factory, however you may also configure it yourself if you feel confident to do so.

Phone numbers are easily changed, deleted or new ones added by simply sending the correct command by SMS from any phone.

Other Applications

The device doesn’t have to be part of a Parabeam® solution. It is useful for many other industrial monitoring applications – whenever you need to be immediately alerted to an even via your phone.

Also incorporated are timers that can be set up to switch something on for a certain length of time whenever one of the inputs is triggered or whenever you send a special SMS instruction to the device from your phone. There are two controllable outputs available.

The outputs are low-voltage ‘open-collector’ type so if you want to switch something that is mains-voltage rated you would need to have a qualified electrician connect a suitable relay or contactor to the device.

On Prepay

The device has a low operating cost, particularly if you have purchased one of several bulk-texting plans offered by the various service providers. For example the plan we typically set up for our customers is the TXT NZ plan through NZ Vodafone and costs $12 per month for 2500 TXTs to any NZ mobile. One thing to be careful of is to always ensure there is adequate prepay balance on the devices SIM card so that whatever TXT plan you are on automatically rolls over every month automatically.

Top-ups can be done on-line providing the SIM card has been registered, or by credit card over the phone (select the ‘top-up a different phone number’ option) or the case of Vodafone at any Westpac ATM.

Our Gate Alarm Is Erratic – Any Suggestions Why?

January 10, 2013

A majority of products sold as a ‘driveway alert system’ or ‘gate alarm’ for use outdoors, incorporate a common type of motion sensor that is not fit for the purpose.   The sensor, known as a PIR, is only reliable indoors where the environment is more controlled.   However they work fine with things like motion activated lights, where it is less of a problem if they switch on occasionally from a false positive.

A PIR based gate alarm will interpret many environmental effects as an intruder, often getting its owner out of bed for no good reason.   It is clearly important that the sensing technology used in a gate alarm is robust and false-alarm free.

PIR Light Activator

The PIR device detects the heat signature from a warm person or animal, or from the motor or tail-pipe of a vehicle.   When the object passes a Fresnel lens array against a backdrop of cooler air, it creates a fluctuating voltage and this is interpreted as movement.   Target objects may be people and vehicles, but in reality all it takes to activate a PIR sensor are alternating currents of warm and cool air, or a tree branch waving in a breeze.

Other factors compound the problem further.   To work properly the PIR relies on an air temperature Goldilocks zone – not too cold and not too hot.  If the temperature is outside the Goldilocks zone, two things can happen.   In cold weather the PIR picks up objects much further out from the sensor, such as animals roaming in a nearby paddock.   In hot weather the PIR sensor may not detect much at all because the high ambient air temperature masks everything else.

PIR Movement Detector

Some manufacturers have tried to minimise these effects by combining multiple PIR elements into one device to augment performance, but this approach is not enough to adequately improve the PIR for use outdoors.

Others have included a microwave Doppler sensor (a variation of the kind used in radar-based speed cameras) with a PIR to give additional verification before activating.   Again, an improvement but increased power requirements makes them impractical for solar or battery power, therefore this kind is typically hard-wired back to a power source.

What is the best outdoor detection technology?

From its inception in 2003, Parabeam® has never considered using PIR technology and instead uses far superior Active Infra-red beam technology.  Two beam-units face each-other forming a beam between them.   This approach is not affected by temperature or rain and requires a solid, real object to interrupt the detection beam before activating.

Other things that make inexpensive gate alarms erratic are weak radio transmitters, internal antennas (or a simple ‘dangling wire’ antenna) poor weatherproofing and poor protection from insect or ant infestations.

Overcoming Connectivity Issues On Hilly Farmland

May 17, 2012

The Problem…

In rural situations there can be obstacles or characteristics of the natural terrain that may create an unfriendly environment for propagating low-power radio signals from our beam communicator to the base receiver. Hills and outcrops of land being the number one issue, particularly if the hill is relatively close to either the gate communicator or the base receiver. Other things to contend with are sheds, dense bush and hedges.

A radio signal from one of our beam-sets can potentially travel several kilometres over say flat farmland in an almost line-of-sight (LOS) situation. However this may be reduced to less than two-hundred metres when impeded by any combination of the above factors. Wet bush after heavy rainfall will cause some signal to be absorbed as well.

At the receiving end, multiple walls and certain kinds of building materials will play their part in weakening the signal too, and on some properties there may be very little left of the signal by the time it reaches a receiving device located in your client’s house.

Radio authorities and solar panel size constraints both restrict the amount of power we can use to ‘blast’ the signal to its destination, and as a result we have developed smart solutions to overcome connectivity challenges of the kinds described.

Solution One: Two-way connectivity

Parabeam® is the first product of its kind to use two-way connectivity. This means signals are sent in both directions between a beam-set and a receiver. An almost instant return signal is a confirmation that everything worked OK. Should the beam-set fail to receive its confirmation it will try sending the signal again – up to three more times. Two-way connectivity is a built-in feature that is a first line of defence in borderline situations.

When a signal repeater is deployed it acts as a go-between, carrying both alert and confirmation signals backwards and forwards in bucket-brigade fashion.

Solution Two: Boost Antennas

It’s well known that an ‘outside aerial’ improves TV reception enormously, compared to a set-top antenna – this is due to a combination of elevation (being on the roof of a home) and the use of a correctly designed, tuned and directional antenna system.

Our design team have developed an outdoor antenna that makes a big difference to a ‘borderline’ signal, boosting connectivity by 5-7 times in many situations. It is common to achieve 2-3kms range using this antenna. Previously the antenna was only available for installation at the receiving end and in most cases that would mean mounting it on the roof of the client’s house.

Recently we have designed a special version of the antenna allowing it to be mounted at the beam-set end instead of the base receiver end – making installation far simpler.
The Diagrams A and B (next page) show how greatly the signal strength can be improved by installing a boost antenna on a site where a small but close outcrop of land impedes the signal from the nearby beam-set before greatly dropping away to a plateau where the house is situated.

DIAGRAM A

DIAGRAM B

Antennas may of course be installed at both the beam-set end as well as at the receiving end to increase the range even more dramatically.
If an antenna located at the beam-set is preferred, a compatible ‘beam communicator’ must be ordered along with the antenna – the antenna can’t be added to a standard beam communicator later because the required connector is not fitted.

This version of the antenna comes with a 6 metre long RG58AU coaxial fly-lead fitted with UHF connectors at either end. The length is deemed ample for the majority of situations and allows the antenna to be installed well above ground level if needed. Any longer and cable losses would begin to subtract from the gain of the antenna.

Overall the resultant signal is 10dB stronger without including the significant advantages achieved from elevating the antenna.

These antennas may also be used in conjunction with signal repeaters (described next) for use on sites where standard equipment and even boost antennas would not have stood a chance.

Solution Three: Signal Repeaters

There are sites that are so challenging that boost antennas alone will not get the signal over a hill or large outcrop of land. Our design team again have developed a solution for this scenario; signal repeaters.

The site shown in the image below had a problem with a large outcrop of land (not easily discerned from the Google Earth image) as well as a large shed preventing much useable signal from reaching the house from the from gate. In this situation there was no need for boost antennas because a signal repeater was installed on a nearby ridge and there was good line of sight from the beam-set to the top of the ridge, and from the top of the hill across to the house.

Beam-sets can either talk to the base receiver using a repeater as a go-between or to the base receiver directly – or a combination of both.

For example; one beam-set may on the other side of a hill and require a repeater while another beam-set is close enough to talk to the receiver directly. This configuration can be set up before the system leaves our factory but may be changed relatively easily later.

DIAGRAM C

DIAGRAM D

DIAGRAM E

Solutions For Theft In The Forestry Industry

May 11, 2012

Battery powered beam-sets

Solar powering a Beam-set in a forestry or dense bush application is often impractical unless there is a reasonable sized clearing in the bush that will allow the solar panels to see enough sky to receive an adequate charge. If there is any doubt, battery powering the Beam-set is the answer.

Fully charge Li-Ion batteries having a capacity ranging between say 2200mAh – 10,000mAh allow operating durations of around 20-90 days respectively. This will vary slightly depending on the number of daily beam activations and the IR Emitter’s beam strength setting, which may be adjusted in three steps ranging from 10m to 40m maximum. Using the 2200mAh example, the physical size of the cell is only 75mm long by 19mm diameter, making it easy to locate near the base of the mounting post without being noticed.

In the case of a 10,000mAh battery pack, a much larger external waterproof housing is needed. (Approximately 80x80x55mm) Regardless of size, external battery packs are connected via a cable to the underside of each beam-unit with waterproof ‘twist-lock’ male and female connectors for easy swapping or removal.

A complete Beam-set kit comprises of a Beam Emitter, Beam Communicator, two or four battery packs and a charger, as well as all mounting hardware and cables.

To help avoid activations from wild animals it may be better to mount the Beam Units slightly higher than the usual recommended height of 800mm above ground. It may also be useful to consider steel poles to help deter possums from climbing them.

Alternatively, a stainless steel band could be fitted around a 100×100 wooden post to help prevent this. Although beam alignment is easy undertake and test, it will be far more important in this kind of remote setting.

Communication via GSM

Assuming there are one, two or several battery powered detection beams deployed, the next question is; how do we communicate beam activations to whoever will be monitoring the site?

If there is GSM coverage in the area there will be very little challenge. All Beam-sets communicate to standard Parabeam® Base Receivers which provide individually zoned trigger outputs to a GSM Communicator. The GSM Communicator then sends an SMS (text message) or makes a phone call to the monitoring personnel, informing them of any beam activation.

The type of GSM unit supplied will typically depend on the number of Beam-sets deployed and how the communications hardware will be powered.

Low Battery Warnings

Though our current GSM technology does not allow remote reporting of a low Beam-set battery, the Base Receiver indicates any low Beam Emitter or Beam Communicator status. Upon observing the battery status, you will have plenty of time to recharge the batteries before a beam-set stops working.

When a fully charged 2200mAh Li-ion battery pack used on each Beam Unit, for example, you will have an estimated 20 days minimum use before a low battery indication is generated, after this you will have around seven days to recharge or swap the battery before the unit stops working. This allows plenty of leeway for maintaining a fully functioning installation.

Communication via Radio

If there is no GSM coverage, a suitable communication solution will need to be devised on a case by case basis. It may be that radio links involving boost antennas and signal repeaters are needed to send the alert signals to a location where there is GSM coverage.

It may also be the case that the site is so remote that communication is almost pointless because of travelling times involved in a site visit. Some kind of local visual and audible deterrent may be used instead of, or as well as communications to hopefully deter trespassers.

Portable cameras such as our high quality RECONYX™ range can also be deployed for a more complete approach.

This article is intended to be an introduction to the kinds of solutions available; however requirements for outdoor, remote situations always vary widely so please contact us directly for a solution to best suit your needs.

Sunblock for Solar Panels

April 15, 2012

In recent years, ozone depletion has increased New Zealand’s exposure to destructive high-energy UV radiation. The Antarctic ozone-layer hole usually breaks up in early summer and this means New Zealand is sometimes affected by ozone-depleted air as it moves over the country.

New Zealand’s exposure to high levels of UV radiation is mainly because of the position of the sun combined with its proximity during summer months, and our relatively unpolluted atmosphere. Peak UV radiation levels in New Zealand can be 40% higher than levels at comparable latitudes such as North America.

The results of this exposure is the premature breaking-down of many kinds of plastics, polymers and resins (as well as the increased risk of skin cancer) Anyone who has purchased cheap solar garden lights will be aware of how cloudy the tiny solar panels go after only 6 months of direct sunlight – this is the epoxy resin breaking down.

Solar garden lights are one example – many imported products intended for outdoor use in other countries often use inexpensive plastics that will deteriorate in no time in the harsher New Zealand sun and this vulnerability must be addressed by any responsible manufacturer.

Our design team have observed complete failure of 3mm thick ABS plastic enclosures within 12 months, eventually allowing water ingress and electronic failure. The same enclosure may have lasted 5 years in another country.

As a result of this information we have taken a high degree of precaution in the design of Parabeam products to ensure they are far more immune to this issue.

Earlier Parabeam® solar panels were dunked in a special UV blocking coating and this worked well to preserve their lifespan however the process was messy and labour intensive. Recent improvements are an integral polycarbonate sheet bonded to the underlying resin which forms a permanent sun-block protection barrier against UV damage.

In addition to this our beam-set enclosures are entirely polycarbonate, as is our front-panel label.

Why Do I Need Onboard Diagnostics?

February 4, 2012

If you have a lot of pine trees on your property you will be only too aware of how much of a mess their needles make as they endlessly fall, covering any flat surface nearby. The solar panels provided with our Parabeam® systems are not immune to the accumulation of fallen pine needles, so over time you can imagine how the system may not receive an adequate solar charge and the internal batteries may gradually run flat.

Our older systems had no way of giving you advanced warning of this problem and the only way you would know something was amiss is when the system just did not work anymore or started giving intermittent service.

Thankfully the diagnostics on the new 700-FSK means there is very little mystery anymore; this model will tell you if one of the beam-units is not receiving adequate charge and allow you to pinpoint the problem easily in the majority of cases.

For example, if you should ever see a red flashing light on say ‘zone 1’ instead of the usual green light, this will tell you to go and check that the solar panel on the ‘beam emitter’ side is clear of any debris like pine needles or grime from a dry dusty road. Once clear, the battery charge will pick up to normal in no time and the red light will return to green by itself.

Another diagnostic indicator is the ‘solid amber light’ – should you ever see this it means something may have permanently fallen in the path of the IR beam, or a vehicle has parked itself there. In this case you would hear the normal alert sounds first, followed 20 seconds later by a series of short chirps. The normally green ‘zone’ light will show solid amber instead, telling you to go and see what object is blocking the beam.

The zone light can indicate four different kinds of ‘trouble’ making it very easy to go straight to the issue and resolve it. Should any issue show up that you are unable to resolve yourself, we will be able to help you resolve this over the phone with the help of the diagnostic indicators.

For more detailed information please read the 700-FSK installation manual.

How To Tell If A Gate Has Been Left Open 2km Away

January 26, 2012

A Parabeam® Beam-set is excellent for generating a reliable alert signal whenever a vehicle or person has passed through its precise detection beam – the base receiver will also tell you visually and audibly that whatever interrupted the beam is still there. For example a car may have stopped mid-way through the beam, blocking it and preventing it from restoring.

But what if you want to know whether a gate on your property is open or closed right now? A beam-set is not really appropriate for a few reasons.
Stock may need to wander nearby and would continuously activate it, and even though you could in principle use an open gate to block the detection beam, the beam could never tell you that the gate is fully closed against the gate post. It would need to be so close to the gate as to be vulnerable to being set off on a windy day.

A better solution is a magnetic reed switch attached to the gate and gate post to sense whenever the gate is opened and left open. Our new switch-link communicator has been designed to handle this very application, and any other application requiring real-time monitoring of any binary state: open-closed / on-off.

When a gate is open the zone LED at the base receiver changes from Green (closed) to Amber (open) – an output also switches on for as long as the gate remains open. You can use this to switch on some kind of audible or visual alert that continues until the gate is closed. This could be something like a strobe light or buzzer.

You can also reverse the polarity of the sensor with a simple jumper (link) inside the ‘switch-link’ unit, so that now the output at the receiver is active when the gate is closed and vice-versa.

The connectivity range of the switch-link communicator is the same as a standard beam-set: 800m maximum, but may be extended dramatically with boost antennas or signal repeaters. Many kilometres connectivity range could be achieved using a combination of repeaters and boost antennas if needed allowing you to tell whether a gate is open or closed right now.

The current model base receiver will monitor two gates, and a switch-link communicator can be enrolled to say zone 1 while a standard beam-set is enrolled on zone 2.

We Have Poor Vodafone Coverage – Will Your SMS Unit Work On The Telecom XT Network?

November 26, 2011

“We have poor Vodafone coverage – will your SMS unit work on the Telecom XT network?”

The short answer to this question is no – SMS devices compatible with the New Zealand Telecom XT network are very hard to source and expensive if you can.

However, all is not lost. If you can get useable coverage outside your house on the Vodafone network – and particularly if you can get good coverage in an elevated location such as on the roof of your house, then there should be no problem making our system work on your property.

In these situations we would supply the SMS unit in a watertight outdoor enclosure. This is supplied with a 15-20m long 6-core alarm cable and incorporates a mounting bracket similar to that of a small television antenna (U-Bolt/V-Block arrangement).

Why can’t the SMS unit stay indoors and we connect an outdoor antenna to it instead? The answer to this is: You can but there will be little advantage and several disadvantages to this approach.

Outdoor cellular antennas are expensive and specialized. Signal losses in the coaxial cable connecting to an outdoor antenna mean only short lengths are recommended or you will lose some of the gain from the antenna itself – this limits the possible mounting locations of the SMS unit.

Coaxial cable at cellular frequencies tends to be very thick and rigid making it difficult to run, whereas thinner, flexible alarm cable can be run much greater distances with ease and is more forgiving if there are kinks in the cable.

In summary, the outdoor SMS is the best solution providing you have first checked for reasonable signal strength at the intended mounting location. The SMS unit has a superior antenna than the one inside your phone, which is designed more for aesthetics than function – this means it will automatically have better coverage than your phone.

If you require more clarification please contact us.