Happy Birthday Sound Lure Prototype!

Today marks a special milestone, if a little unusual.  We have a unit celebrating its birthday.   Normally such things would a little issue, but this is relatively significant.  

Our remaining test unit (pictured) has now been operating for a calendar year.   It has done so with the original solar panel (pictured) and the original speaker (which were purchased from Ali-Express for $12.00 NZ and $2.00 respectively.   The unit itself, contained within the IP rated box, connected via bolts has remained working throughout this time and continues to work.    The speaker is showing some sign of wear and tear but it is cardboard based and it has been exposed to the elements, including being deployed in New Zealand for the Winter.     These conditions have included heavy rainfall and the unit has continued to operate either placed inside exisitng trap devices (such as a DOC 200 or DOC 250) or inside a rat tunnel box.  It has also at times been placed directly on top of various traps and locations which has exposed it directly to the elements.

We also have deployed a similar unit to the South Island where it was able to operate in temperatures below freezing (as indicated by the temperature reading from the trail cameras operating in conjunction with it.   We also have had two early versions of the unit at the New Plymouth Airport.   These have been in place since June and are still continuing to operate as expected, despite featuring the original solar panelling (which we have effectively doubled in size since we started).   The final piece of the puzzle being the speakers, which we have just accessed today. 

In summation we believe based on the deployments that have already occurred that we have a unit that is able to operated in external conditions which is reliable, can operate independently and can do so for at least a calendar year (although of course in this case, this is a signpost rather than an end game).

Final Prototype Deployment Activations/Weather Situations

Following three days of rainfall, wind and generally poor weather there has been two significant activations on the single unit deployment at site one.   There are three issues here that are worth noting. 

Firstly the IP Box which has been waterproofing the main portion of the electronics has work as expected.   There has been three days of rain and while the box has been at the base of a tree offering it some basic protection (as opposed to being placed inside a trap box as eventually it will be) the unit has been exposed to the elements.   We have stated that the solar panel and speaker are being housed separate from the main unit and they are more exposed to the elements, and there was evidence of rainfall on both.    For the main unit there is no evidence of moisture inside the box itself which is housing the main electronics (and the expensive parts of the units, see 'economic breakdown' in a different post on this blog).

The two activations that are present shown on the camera are represented by a cat which can be seen in the above photo.  It is clearly seen on a series of photos that take place at 8:25pm.   As noted the camera needs to be reset so that it reflects daylight savings and the correct year.

We have shown evidence in the past of the unit with the basic sound profile (which we are using again for current testing) which has two possum sounds, two chick sounds and a stoat sound consistenly attracting cats and feral cats to the unit.  The second activation which can be seen clearly in the photographs is the large brush tailed possum which arrived at the unit and was in the vicinity of the unit at 9:15pm. 

The final issue relating to the unit is again the question of the battery unit and solar panel charging.  There has been three days of rainfall and overcast weather.   The suspicion is that this has limited the ability to charge the unit.  There is clear evidence that the unit has been working during darkness (as shown by the photographs) however by the early morning the unit has stopped.  This is something that has been experienced with the unit.   The speaker deployed with this unit is a 4w speaker.   Once the unit has been moved into morning light the unit has started immediately operating exactly as expected (using the day profile).    We are going to run trials with different strength speakers and also experiment with the solar panel in a location that has more direct access to sunlight, in addition we are charging the unit fully in daylight (solar) and will then place it in semi-shade for the deployment.

Final Prototype - Brief Demo

This is a brief demo and explanation of the final unit prototype as it is deployed:

Final Prototype Deployment Now in Progress

Final deployment of the unit to run until 2021.

We have now reached the point where we have made what we believe will be the final design for the sound lure, which is being placed in an outside rural position indefinitely.    Since November we have been deploying and adapting the design, including spending extended time checking the units viability.

Waterproofing: This has been a key issue for the long term viability of the unit.   Initially we designed 3D Printed boxes created by students in the classroom to protect the first run of the boxes, while this worked against rain of varying levels particularly when it was combined with a wooden stoat or rat box.    Given that the

Above: External bolts to show exit points

first trials were taking place over Summer or Autumn, we were aware of an increase in condensation during Winter that would cause difficulty with the units.    The solution as detailed on this blog we believe has been to use IP Rated Waterproof boxes.     These boxes have extremely limited ability for water to enter them.   By drilling two bolts holes into both end of the boxes and placing two bolts into both sets of holes, and then protecting the gap between the bolt and the box, this should make the units essentially waterproof.   We will be leaving the unit pictured above outside for an extended period of time (intended to be the rest of the year) to ensure that it is working.  We do have questions over the two parts of the unit that are currently external, the speakers and the solar panel.  Compared to the rest of the unit these are relatively inexpensive and somewhat disposable but this also allows the set up to be flexible.

Battery/Power Level: Every indication that this has been resolved.  The oustanding issue is the weather proofing of the solar panel unit and the long term lipo battery use with the unit.    The batteries are charging each day, overtime we would expect there to be a drop off in efficiency of them as a unit.  We are undertaking to work with solar panel experts to indentify the size, durability and cost price of the best unit for moving forward (long term) with the project.    We have versions of remote monitors to constantly check the battery level for the device.   We have a cut off point for the device to shut down if the battery level is too low.   In full sun there is no question that the device is able to maintain itself on a daily basis, running all day, having the unit charge during the day and then play all night, maintaining enough charge to complete and re-start the cycle.   In full shade the unit is able to operate from a mains charge for four days without requiring any additional charging. 

Brust Tailed Possum interacting with Sound Lure

We are currently investigating the viability of the unit to run in partial shade on a full time basis - we believe that it will but are currently finalising our testing to prove this.   This is important because it would mean the unit could be used in bush/vegetation situations where it could be left.   We are focussing in the future on stoats in particular.   The goal is to have a self managing sound lure that can be left long term to attract predators without the need for it being either monitored or powered up etc.   This would be possible only if the unit could be left in position and would not require any additional human interaction (such as changing the batteries etc).

Water Proofing dealt with by the commerical grade nox

Developing the Picaxe Chip Further:
Now that we believe that the waterproofing and power levels have been resolved we can move forward with adjusting the sound levels and profile, this is where the Picaxe chip will come into its own.  The current setup includes a basic 1/5 profile, that is one sound during the day and one of five random sounds at night, played randomly.   With the system set up including the code from the computer the number of sound activations during the day or night are limited only by the size of the mini-SD card are contained within the unit.  Potentially this could be expanded on considerably.   The current coding set up is to reflect its development in the design process, it was essential to develop the water proofing and the circuit design to the point that it was successful so that the coded version of the computer/Picaxe could follow last.   Once we start talking to individuals and partnerships we can target specific time when the unit activates (as it is reading the light level from the solar panel), the frequency with which the unit operates (again based on specific times/light levels).  We are also able to introduce a variable into the unit determining the frequency and the volume at which it is required to operate.   There are nearly unlimited variations that can be easily introduced and coded into the unit.

Cost of the Units: Throughout the process we have attempted to minimise the cost of the unit.  The purpose of this is to ensure that the technology behind the unit and the units themselves are as accessible as possible to the widest range of individuals possible.   The units that are featured on this blog, the latest versions of them, have been created/produced by ten year old students.    We are currently able to create a unit in the region of $50.00 for the entire existing set up, with a further $20.00 required to ensure that the water proofing is complete.   While we cannot look to answer the question of how long that the unit itself will last for we are hopeful that with the steps that have been taken it will remain in operation, in authentic outside environments without needing to be modified or human interaction and the final step is to measure its effectiveness in as many locations and situations as possible.

If you would like to assist in doing that can you please contact us via email (myles.webb@gmail.com) to discuss the matter further.