Is there an electronic equivalent to transmission?

[GreenAce92]

I was thinking of a device to build, it would be a sensor connected to a basic phone with sms capability. It would be say a Raspberry Pi connected to a simple DC motor with a propeller(waterproof).

There is this road that is paved over a creek, it's usually always submerged by a couple inches of water, but yesterday after some rains, it was at least 6 feet deep. As far as I know there's no way to know when this road is under water/flooded.

So the sensor/phone would be made to send out a signal telling you when the road was under water... now that I think of it, the phone probably has to be outside of the water proof sensor/computer/battery. Phone also has to be powered... anyway I would then communicate to another phone and then update a website.

The electronic-transmission part has to do with the motor, if the battery is charged, but the motor is still spinning producing energy, how do I prevent this energy from going into the battery/system? Do you need a mechanical transmission like a servo sliding a slip-ring or something like that?

 

[betwixt]

I'm not sure if you are saying the motor is a motor or it's a generator. I suspect you are using it as a generator. As you are not using any excess power it might generate, just regulate it's output to keep the voltage at trickle charge level for the battery and a split off it to a regulator for the phone/Pi. If the motor produces more voltage than necesary, it just gets turned into heat in the regulator, I would guess the amount of heat in a system like that would be fairly small and easy to deal with.

There is a mechanical solution but I doubt it's worth the effort - you fit a tail fin to the generator but offset it at an angle. As the water flow increases it pushes the fin further to the side and moves the propeller (impeller) out of the line of flow so it gets less 'push'.

Brian.

 

[GreenAce92]

I'm not sure if you are saying the motor is a motor or it's a generator. I suspect you are using it as a generator. As you are not using any excess power it might generate, just regulate it's output to keep the voltage at trickle charge level for the battery and a split off it to a regulator for the phone/Pi. If the motor produces more voltage than necesary, it just gets turned into heat in the regulator, I would guess the amount of heat in a system like that would be fairly small and easy to deal with.

There is a mechanical solution but I doubt it's worth the effort - you fit a tail fin to the generator but offset it at an angle. As the water flow increases it pushes the fin further to the side and moves the propeller (impeller) out of the line of flow so it gets less 'push'.

Brian.

Hi Brian, thanks for your post.

Yes I did mean to say "use the motor as a generator".

Your idea sounds more applicable than a complicated clutch with a servo, more potential to fail.

Yeah I was concerned about the heat as well, if I had a heat sink that stuck out of the water proof case, then the heat could be channeled through here I would think...

I also thought about a fixed-rpm variable-pitch spring-loaded propeller. Where the faster the propeller spins due to the flow of water, the centrifugal force affects the propeller... it sounds super complicated, I envisioned a cone-shape with the propellers, and the spring holds the propellers back, but as it spins faster, the blades swing outwards, and change pitch accordingly like a swash-plate on the tail-rotor of an rc helicopter.

That sounds ridiculous and I haven't looked at the mechanics if it even makes sense.

Other problems involve possibility of theft, having to hide the components, the phone has to be separate from the waterproof device to get a signal, possibly need a solar panel(other form of energy) when there is no water at all.

Anyway, thanks for your input.

 

[betwixt]

I agree there is no point in making a complicated mechanical arrangement, especially when the benefits are marginal and it would be so much more prone to breakdown and environmental conditions.

For the 'phone' part, if you are prepared to do some programming, the solution would be to use a GSM module and sim card instead of a complete phone. It is smaller, (~30mm square), draws far less power from the battery and has an external antenna connection. It also works around the need to mechanically press buttons or move a pointer around a touch screen to enter data as it is all done through three wires. Sim modules cost far less than phones too!

What exactly do you want to measure, is it water flow rate or water depth or both? The electronics needed to drive a GSM module are simple and easily expanded to take measurements and report them as well as just send fixed messages. For example, if you use your 'mini hydroelectric power station' method you could measure impeller rotation rate to report the water flow rate or for depth, either use resistive, capacitive, float switches or even optical methods.

Brian.

 

[GreenAce92]

I agree there is no point in making a complicated mechanical arrangement, especially when the benefits are marginal and it would be so much more prone to breakdown and environmental conditions.

For the 'phone' part, if you are prepared to do some programming, the solution would be to use a GSM module and sim card instead of a complete phone. It is smaller, (~30mm square), draws far less power from the battery and has an external antenna connection. It also works around the need to mechanically press buttons or move a pointer around a touch screen to enter data as it is all done through three wires. Sim modules cost far less than phones too!

What exactly do you want to measure, is it water flow rate or water depth or both? The electronics needed to drive a GSM module are simple and easily expanded to take measurements and report them as well as just send fixed messages. For example, if you use your 'mini hydroelectric power station' method you could measure impeller rotation rate to report the water flow rate or for depth, either use resistive, capacitive, float switches or even optical methods.

Brian.

Wow that is so much better than what i had in mind. For some reason I just had it pictured that I would have some sort of USB plugged into the phone, but what you said makes a lot of sense.

All I was looking to accomplish was to say that the road was flooded (impassable) say at least 1 ft deep of water. It surprised me late at night when I was going to bike through there and the deep-area with the road was covered with water up to 6ft (in the dark), insane.

I suppose even a simple bobber would work, at least 1 ft it would be in tension mode, pulling a tension-click-switch.

This probably won't work well because of the flow, there probably isn't much of a distinction between the pulling of the water-flowing, and bouyancy force.

I would be down to do some programming, I'll have to see what language it is, not sure if it's C/Assembly or something different like AT command or I2C.

Anyway, this is great information, thanks again.

 

[BradtheRad]

I suppose even a simple bobber would work, at least 1 ft it would be in tension mode, pulling a tension-click-switch.

This could work if you put the bobber inside a vertical tube. It would be on a string which hangs from the switch on your device. Or else use a float switch.

Your device is in a tree (utility pole, etc.), away from the water, out of sight.

Have you considered led beam? Toy laser pointer? Homemade micro-power radio transmitter?

 

[GreenAce92]

This could work if you put the bobber inside a vertical tube. It would be on a string which hangs from the switch on your device. Or else use a float switch.

Your device is in a tree (utility pole, etc.), away from the water, out of sight.

Have you considered led beam? Toy laser pointer? Homemade micro-power radio transmitter?

I did consider alternatives, like possibly connecting a bridge between two points using water, if there is no water then the connection isn't complete. Not to say running high voltage or high current through water... I meant using the water as a medium to connect... eh. Anyway, I did not consider a laser or micro-power radio transmitter. I did think about possibly detecting the presence of water with a beam but reflection didn't make sense, probably slowing down the return of the beam if it was bounced off of something else.

A lot of possible solutions, I do like the concept of bridging the sensor to a phone to a computer/server. Would be great to accomplish that.

Thanks