data logger

We'd like to create a prototype for a device that sends a SMS every time the device comes out of water. The device will be submerged in sea water for around 12 months from a depth of 3m to 50m. It will be pulled to the surface every day. It will remain out of the water for 1 minute to 5 minutes. When it breaches the surface, it will immediately send a SMS advising: 1. ID 2. Date and time it breached the surface 3. GPS coordinates (latitude and longitude) 4. Battery voltage The device needs to be battery powered and work off a 3G cellular network. I will supply SIM. Operation will be in Australia. As a prototype/proof of concept, it would be expected that the battery will last at least 1 month and use readily available and cheap batteries eg. AA. Future refinement will see battery life extend to 1 year. We will provide the underwater housing, so this does not need to be designed at present. We believe the hardest part will be determining how to activate the device. Options considered: 1. Pressure sensor - when the sensor reads normal atmospheric pressure, it sends SMS. 2. Water sensor - these sensors detect the presence of water. Water across the probe allows current to flow, indicating it is still in water. This type of sensor is not favourable because of the limited time the device will be out of the water. It does not provide an opportunity to dry across the probe, hence a SMS will not be sent. 3. Float switch - When float is up, device is off. When float does down (as it comes out of water), device turns on. There are several issues with this including 1. float arms are very likely to break 2. Device will seldom land flat. Whilst the device is out of the water, it will send a SMS every 30 minutes. When it is back in the water, it will cease transmitting. There may be ways to overcome the challenges faced using the proposed sensors. Perhaps you have a different idea - we'd love to hear about it. We believe the sensor will be the weak point in the device because it needs to be exposed to some extent, hence our focus on this area. Other parts will remain within the housing. It must be remembered that these will be deployed in a very harsh environment including salt water, complete immersion, pressures up to 5 ATM, substantial impact from being knocked about reefs, seas and swells exceeding 6m, marine growth, and being attacked by inquisitive marine animals. It also needs to be able to immediately recognise when it comes out of the water. The device will work from a 3G or 4G network. It will use GPS or GPRS to obtain latitude and longitude. We are concerned about GPS draining the battery quickly. We are concerned that GPRS may not work as the device will be located approximately 5-6km from the nearest tower, and signal from other towers may not exist, be unreliable, or non-existent. When selecting components, please consider quality, availability and price. Components should be able to be sourced easily, especially in Australia and India. Deliverables for this project include: 1. Provision of design documents, codes, parts list, construction instructions etc.. It is expected that this can be taken to any electrical engineer who can develop exactly the same device - no questions asked. 2. The prototype itself. We expect that deliverable 1 will be performed so well that we can order the components and construct ourselves, and upload code to make it work. 3. Intellectual Property - all IP will be handed over. As much as we like you, we want to be able to shop the design around for large scale manufacturing, or build it in-house using your detailed instructions. 4. Product cost - we want the cost of the components clearly outlined, along with construction time ie. how long will it take someone to construct this when they have everything in front of them. We will be testing the prototype and will have to work with you to develop the product further.