Issues 7/15
- Tested out the new power supply. It was able to deliver constant voltage with all 8 wind sensors.
- However there's the issue that the last two sensors hooked up are outputting higher voltage than the 0-3.3 V range that is expected. around 4 or 5V.
- When the current was higher these two sensors were getting much more hot than they probably should have been, at least much hotter than the other sensors.
- I checked the connections and tried changing the sensors that were plugged in but that didn't seem to change anything.
Stubbs comments- OK, good! Thanks for the update. Here's what I suggest:
It could be the power supply issue you encountered isn't due to too many sensors, but rather either a wiring/construction error or outright sensor failure. We need to figure out what the problem is (Duh).
Possibilities include:
1) all sensors are OK but some of the connector positions are fouled up, i.e. problem lies inside the box, not outside with the sensors
2) One or more of the sensors have a problem, for some reason.
3) Other (I put this down because a major way to fail in science is to make a list you think is exhaustive and includes all possibilities, but doesn't!).
Although we never wrote it down, our earlier hypothesis was that the overall system was drawing more current than the power supply could deliver, and that otherwise everything was fine. I think we have now eliminated that prospect.
Here is my request: be really specific and fill in this table with your version of hypotheses and experimental tests. You kino of did that implicitly a bit above, but let's be really specific. Then you can do the tests and fill in the outcome column. Welcome to the scientific method! Sound OK?
| hypothesis | test | outcome |
|---|---|---|
| Sensors have some kind of problem | Change out a sensor with one of the spares | This seems to bring the voltage closer to the 3.3V max but is still slightly above, ~3.7V |
The sensors can run between 9 and 12V, with 12V being the "optimal," but maybe they just need to run at a lower voltage. | Change the voltage | This seems to get most of the sensors within the proper range, but I don't know if this is the ideal way to achieve that. |
Issues Encountered
- When all 8 sensors are plugged into the Lab Jack, the sensors output very small voltages. The voltmeter reads out a cycling voltage. It seems to be a problem with the power source.
- With the outlet by in the office it seems it can only deliver constant voltage to 1 sensor. More makes it cycle
- With an outlet by the lab bench, it can deliver constant voltage to 5 sensors. The 6th makes it cycle
Wiring for the Sensors
The purple and brown wires represent the positive and ground ends respectively. The sensors are all wired in parallel to each other.
The green wires are the temperature outputs. The red wires (red in diagram, orange in photo) are the wind speed outputs.
Sensor Assembly
Wed June 22
- Epoxied the flanges to the carbon fiber tubes
- To Do:
- Create/have made an assembly for 8-10 of the DB 9 cable connectors within the box for the lab jack
- Put together wiring for the power supply
Tues June 21
- Cut and filed more carbon fiber tubes
- Assemble 7 more of the wind sensors connected to DB9 ribbon cable in tubes
- Test that all of the electronics were working
Mon June 20
- Assembled shelves at storage unit
- Loaded U Haul with lab equipment
- Moved Equipment into storage unit
- Lunch at Shang Cho afterwards
- Fried rice
- Honey Comb PB Pretzel ice cream
Fri June 17
- Got a lesson about screws, and read more about screws
- Installed lab jack software on Mac
- Hooked up one wind sensor to the LabJack to test it out while connected to the Mac
- Cut one carbon fiber tube in half and assembled one of these sensors with stands without any adhesive. It fits well, the ribbon cord needs to be pushed in.
- Need to learn how to write code to get from the voltage numbers to wind speed
Thurs June 16
- Mapped out the wind sensing system
- Completed online general lab safety course
- Completed online physics machine shop and Makerspace safety course
- Hooked up the hot wire anemometer to a voltmeter to test it out
- GND-White 5
- +9-12V -Violet 4
- OUT - Orange 2
- TMP - Green 3
- SHDN - Brown 1
- Like so:
- Knotted cable is ground
Wed June 15
- Met the group and learned the basics of some of the various projects
- Learned to use the coffee machine !!!
- Learned to solder and soldered right angle pins onto the wind sensors
- Set up a Mac mini