and it looks as if I ought to be able to convert the output to a web-viewable format. but i know from nothing about arduino and the systems that seem to be used for that these days.
Can someone point me to some resources for getting the output of this gadget online? I can work out how to calibrate it (use a 20 piece of PVC full of water and mark the cable every foot and record the outputs).
The tide range where I am in Maine runs up to 15 feet.
You may have to do some work to get that sensor to work for you, it may not be as sensitive as you’d like to have. As I figure it, a full scale range (FSR) of 400 psi = 20 mA = 5 V (using a normal current loop receiver) = 865 ft depth. So 15’ is only 1.7% of the FSR. W/o additional amplification that’s only 18 lsbs of change. What level of resolution were you looking for ? What particular model did you get ?](SparkFun WiFi Shield - CC3000 - DEV-12071 - SparkFun Electronics)
lobsterman:
Been trying to work out how to build my own tide gauge. Was going to use iobridge hardware but they’ve stopped selling it. I scored this item on eBay
and it looks as if I ought to be able to convert the output to a web-viewable format. but i know from nothing about arduino and the systems that seem to be used for that these days.
Can someone point me to some resources for getting the output of this gadget online? I can work out how to calibrate it (use a 20 piece of PVC full of water and mark the cable every foot and record the outputs).
The tide range where I am in Maine runs up to 15 feet.
Pointers and suggestions most welcome.
If it’s for measuring tides, the link you gave is an expensive intrinsically save sensor for fire/explosive areas. You might want to look for an equivalent that’s less expensive if for fresh/salt water.
Once the sensor is selected, it’ll be easy to network it.
It may seem like overkill but the salt water environment there in Maine sometimes freezes and it will unattended for months at a time.
Once the sensor is selected, it’ll be easy to network it.
Pointers here would be much appreciated.
I’m working on an online sensor project using a BeagleBone as my spare time permits. PM me if you want to share code when you get to that point. I’m trying to instrument a mousetrap
It’s not hard, but it has taken me so long to get all the information together, I’ll probably post it somewhere accessible so others can use what I learned. Seriously, for what should be a simple thing to do, there is very little online that puts it all together instead of just little chunks of knowledge.
lobsterman:
Been trying to work out how to build my own tide gauge. Was going to use iobridge hardware but they’ve stopped selling it. I scored this item on eBay
and it looks as if I ought to be able to convert the output to a web-viewable format. but i know from nothing about arduino and the systems that seem to be used for that these days.
Can someone point me to some resources for getting the output of this gadget online? I can work out how to calibrate it (use a 20 piece of PVC full of water and mark the cable every foot and record the outputs).
The tide range where I am in Maine runs up to 15 feet.
Once the sensor is selected, it'll be easy to network it.
I could use some pointers to how to connect this device to an arduino gadget. Tutorials?
Typically, a 4-20 mA device is read using a resistor in the current loop, and measuring the voltage drop across the resistor. Google will show you how to do that. You’ll need to put the analog voltage from the resistor into an ADC input on the Arduino (or any other micro). You may need a resistive divider if the voltage is to high, or, more likely, an op amp if it’s too low. I looked into reading a 4-20 pressure sensor a few years ago but never got past Googling how to convert 4-20 into a voltage.
After that, it gets treated like any other analog voltage so any Arduino sketch that uses the ADC will work. Putting it on the web is a whole other ball of wax. If I were looking to make a web based instrument of any kind (weather station etc), I think I would look closer at the Rasberry Pi. The only drawback of the Pi is no ADC input, so you’d need an external ADC with a serial output. But I think putting anything online may be easier with a real OS.
In the above you may eliminate the U1A op-amp and instead connect the “top” of the resistor to the analog input pin of the Arduino. You need to find out what the allowable “sense” or load resistor range is. It will probably depending the power supply voltage. The higher the PS voltage, the larger the sense resistor (100 ohms above) can be and the larger voltage it’ll produce, giving you more resolution.
Z1 is a zener diode, to protect the Arduino’s input. A value of 4.9 to 5.1V should be OK for a 5V Arduino.
I echo what Dave said. The reason I’m using a BeagleBone is I wanted to experiment with putting some devices online with a nice UI and BBB serves up webpages easily. Unlike the RPi it has analog inputs, but it is twice the price. Still a great deal though.
I am overwhelmed by the apparent options available for accomplishing this, and frankly, by needing to deal with the learning curve of programming Arduino, etc., boards. The virtue of the hardware once produced by iobridge was simplicity: hook it up and set up the dashboard but I don’t see anything which replaces that approach out there now; am I missing something here?
No, you’re not missing anything. It can be complicated and there are 50 ways to skin this cat. So start with the simplest and cheapest (in terms of hardware) and see if it works. Start with a 12V battery, your sensor and a 100 ohm resistor (as the “receiver”) as shown above. Then just use a DVM to measure the voltage across the resistor instead of some micro or SoC. See if the voltage varies with the tide as you expect. Even better … with a high tide, drop the sensor into the water, stopping at various known depths, and see if the resulting voltages make sense (0.4 - 2.0 V). Try it w/a 200 ohm resistor though you may have to increase the supply (12v) voltage.
If that works then proceed with a “puter” of some sort (and it’s ADC) from there. If it doesn’t work then you’ll need a fancier “receiver” than a 100 ohm resistor. Come back an report your results and “we” will take it from there.
As I mentioned earlier, I’m working on a similar project. If you have (or want to purchase) a BeagleBone, I have some basic code that I can share with you.
Currently I’m monitoring a mousetrap and air temperature and putting it up on a simple webpage. If you’d like to experiment, contact me via private message. The temperature monitoring code should work for your tide gauge.
