Week 12

This week Dana and I made good progress on our ROV and sensors. Dana’s hydrophone is completed and will have a tether to the surface, where sound can be recorded and heard in real time. My light sensor should be completed next week. This week I mostly worked on the programming aspects of it. It will now log data from the light sensor every second. There are 512 bytes of data in the eeprom memory of Arduino, so this will provide me with about 8.5 minutes of data. The analog output is from 0 to 1023, however the eeprom memory only stores values between 0 and 255. So I will have to divide the output of the sensor by four before saving it to eeprom. I’ll put the sensor inside something to block white light (maybe a piece of PVC) and place a red filter over the top of that. I’m also interested in building a depth sensor, because it would be nice to have the depth the light measurement was taken at.

            Last night I went up to the lab with Colin for a bit and discovered that I would be able to use conductivity to detect when the ROV is submerged. When I put a wire at 5v in water with a wire connected an analog port, the output jumps right up to 1023. Next step is to test it with pool water. I was hoping I could use this same method to detect when the ROV leaves the water. However, I am worried that having 5v constantly sent to a wire in the water will drain the battery. If this were the case, I can program the Arduino to cut power to that pin after it detects 1023. In any case, I already wrote the code to wait for 1023 on analog 1 then start logging light data on analog 0. In addition I hope it will start logging depth on analog 2, but I guess I need to look into how difficult a depth sensor is.

            Overall, our ROV is coming together nicely. My next step is to solder a 5v voltage regulator and a light sensor to wires that will connect it to the Arduino board. I was worried at first, but at the rate Dana and I are going we should have plenty of time to build our ROV.