Dear all,
I have an idea for a product. For understandable reasons I do not want to disclose it entirely at this point, but electronics part is just that - electronics.
Imagine there is a device, that needs to sit under water (up to a few metres deep) and be able to monitor a hall sensor for 'magnet' or 'no magnet'. It also needs to notify the owner of the device by sending an SMS if the status has changed and possible once in 24 hours just to say it is still alive, but there 'are no news'. There can be several of these devices in an area - say a few hundred metres apart from each other. The device does not have to be tiny, but bulky is also not an option. The size of a wristwatch would do. Think the bulkier versions if you like.
It will need power - could be Lithium coin cell. It will need to be re-charged - know how to do that from my miniature wireless charged cars project.
It cannot have openings for SIM cards and it will be difficult to build an enclosure watertight enough if it is possible at all. Also, it would not be very practical for the owner to maintain more than one mobile connection if he owns several devices, which is likely.
So, we need a basestation of some kind. Potentially, underwater devices communicate to the base station their status every 5 mins to 1 hour over RF. Here comes the unknown:
1) I know how to build bluetooth solution small enough, but it would not reach a few hundred metres needed;
2) I have no experience with other types of RF and pointers would be appreciated - an ebay module will not fit the size requirement, however attractive from price and simplicity perspective;
3) Radio waves are said not to travel well in the water. However, I do not really need well. I need something like 'device one;battery OK;closed', 'device two;battery OK;open'. That is a single byte of information at most that needs to get through;
Then, when we have many devices, we need to be able to see all of them are connected to the base station and are ready for communication. So there needs to be some sort of handshaking and getting to know each other. One way would be to have a device with a UUID in the underwater thing, but that would be a lot of bytes to send every time. Of course, aliases could be assigned to each device after handshaking has taken place once, but this introduces two-way communication.
4) Does picaxe/pic have some unique ID that would be unique enough for this sort of purpose?
The base station part of integration to some GSM/GPRS module, power management and some setup interface via bluetooth or computer are all things requiring some work, but no particular challenges that I can see at this point.
When I have written it all up it sounds a bit like an IoT project of some sensors scattered around a building and connection to a central hub every now and then, except mine would lay under water . Of course this could be complicated with GPS in each underwater device and some smart phone app that would let you see where your underwater gadgets are etc., but that should probably stay for later.
All ideas and feedback welcome and thank you in advance for your input,
Edmunds
I have an idea for a product. For understandable reasons I do not want to disclose it entirely at this point, but electronics part is just that - electronics.
Imagine there is a device, that needs to sit under water (up to a few metres deep) and be able to monitor a hall sensor for 'magnet' or 'no magnet'. It also needs to notify the owner of the device by sending an SMS if the status has changed and possible once in 24 hours just to say it is still alive, but there 'are no news'. There can be several of these devices in an area - say a few hundred metres apart from each other. The device does not have to be tiny, but bulky is also not an option. The size of a wristwatch would do. Think the bulkier versions if you like.
It will need power - could be Lithium coin cell. It will need to be re-charged - know how to do that from my miniature wireless charged cars project.
It cannot have openings for SIM cards and it will be difficult to build an enclosure watertight enough if it is possible at all. Also, it would not be very practical for the owner to maintain more than one mobile connection if he owns several devices, which is likely.
So, we need a basestation of some kind. Potentially, underwater devices communicate to the base station their status every 5 mins to 1 hour over RF. Here comes the unknown:
1) I know how to build bluetooth solution small enough, but it would not reach a few hundred metres needed;
2) I have no experience with other types of RF and pointers would be appreciated - an ebay module will not fit the size requirement, however attractive from price and simplicity perspective;
3) Radio waves are said not to travel well in the water. However, I do not really need well. I need something like 'device one;battery OK;closed', 'device two;battery OK;open'. That is a single byte of information at most that needs to get through;
Then, when we have many devices, we need to be able to see all of them are connected to the base station and are ready for communication. So there needs to be some sort of handshaking and getting to know each other. One way would be to have a device with a UUID in the underwater thing, but that would be a lot of bytes to send every time. Of course, aliases could be assigned to each device after handshaking has taken place once, but this introduces two-way communication.
4) Does picaxe/pic have some unique ID that would be unique enough for this sort of purpose?
The base station part of integration to some GSM/GPRS module, power management and some setup interface via bluetooth or computer are all things requiring some work, but no particular challenges that I can see at this point.
When I have written it all up it sounds a bit like an IoT project of some sensors scattered around a building and connection to a central hub every now and then, except mine would lay under water . Of course this could be complicated with GPS in each underwater device and some smart phone app that would let you see where your underwater gadgets are etc., but that should probably stay for later.
All ideas and feedback welcome and thank you in advance for your input,
Edmunds