VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics


Go Back   VAF Forums > Main > RV General Discussion/News
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 05-26-2014, 04:34 PM
DanH's Avatar
DanH DanH is online now
 
Join Date: Oct 2005
Location: 08A
Posts: 9,500
Default Test/Measurement Electronics Help?

I have very low electronics design skills. Can you tell me what I would need in order to read temperature and humidity using this chip assembly?

http://www.digikey.com/product-detai...366-ND/4732682

http://www.ge-mcs.com/download/moist...20-628A-LR.pdf

I gather it needs a microprocessor. Cheap and easy? Not so easy? Requires writing code? Alternate sensors or devices?
__________________
Dan Horton
RV-8 SS
Barrett IO-390
Reply With Quote
  #2  
Old 05-26-2014, 04:56 PM
YellowJacket RV9 YellowJacket RV9 is offline
 
Join Date: Oct 2012
Location: Clearwater, FL KCLW
Posts: 1,281
Default

The specs says it uses an I2C output for the data. The solution that comes to mind to me would be to use an I2C to RS232 converter to send that data to a PC. Google brought up several options. Other options would be using a small microcontroller like the TI MSP430 (only one I am really familiar with) to read in the I2C data, format it, and then send it to an LCD display, many of which also use I2C. Or, simpler may be using an experimenter's board like an arduino which are pre-wired for I2C inputs and outputs. The last two options at least would require some electronic assembly and programming.

I can try to provide some more details if you like, but I left engineering to be a fireman, so I'm sure there's somebody more knowledgable than me A little research on I2C may be a good start.

Chris
__________________
Chris Johnson
RV-9A - Done(ish) 4/5/16! Flying 4/7/16
Reply With Quote
  #3  
Old 05-26-2014, 05:15 PM
N804RV's Avatar
N804RV N804RV is offline
 
Join Date: May 2013
Location: Mount Vernon, Wa
Posts: 643
Default

I like the Arduino controller. Easy to do and plenty of "how-to" info on the web for non-engineer types.

http://arduino-info.wikispaces.com/P...midity-Display

Once you're done prototyping, the whole thing can be neatly packaged in a small housing that could be mounted to your instrument panel.

You will have to make a powersupply for it if you're gonna wire it to ship's power.
__________________
Ken W.
Mount Vernon, WA
2020 VAF Supporter

Last edited by N804RV : 05-26-2014 at 05:28 PM.
Reply With Quote
  #4  
Old 05-26-2014, 05:43 PM
larosta larosta is offline
 
Join Date: Dec 2010
Location: Redlands, CA
Posts: 176
Default

Dan,

It depends on how you want to use the information form the sensor. If you want to be able to display it in real time in the cockpit you will probably need a microcontroller of some sort, a display, power supply, and some software written and programmed into the microcontroller. The Arduino controller is pretty easy to configure for an application like this.

Sparkfun has several humidity sensors and there is a good support community there that may be of use to you.

Here is a link to one humidity sensor and some Arduino application information for a humidity sensor application.

https://www.sparkfun.com/products/10239


If you want to record the information for later analysis and review you will probably want a superset of the above.

If you want to just display the data on a laptop there are several solutions as described on the earlier post.

If you can be a bit more specific in what you want to do the community can probably get you closer to a viable solution.

Phil
Reply With Quote
  #5  
Old 05-26-2014, 06:35 PM
NDrv8r's Avatar
NDrv8r NDrv8r is offline
 
Join Date: Dec 2009
Location: Bismarck, ND
Posts: 212
Default humidity sensor

Hi Dan,
It would need some code somewhere, either with a I2c to RS232 adapter or directly to a LCD display. I did a similar project using a couple of pressure sensors for cowl pressures using a Microchip product.

Let me know what the end game is for this unit, but bottom line is some coding will likely be necessary.
__________________
Larry Buller
RV7A slow build, Tip up, IO360 200hp, Catto 3 blade, Dynon Skyview, arinc 429, ems, SV transponder, Garmin GNS430w, Aera 560, Dynon D6.
FLYING!
Reply With Quote
  #6  
Old 05-26-2014, 06:57 PM
pczar3's Avatar
pczar3 pczar3 is offline
 
Join Date: Jul 2005
Location: Bolingbrook, Illiniois
Posts: 254
Smile Here's a complete solution

Hi Dan,
well you leave me amazed with some of your building but you're in my area now. Here is a link to a complete Temperature/Humidity display based on the Arduino and it has the code with it as well. Take a look and see what you think.

http://arduino-info.wikispaces.com/P...midity-Display

Let me know if I can help.
Paul
__________________
Paul
N694BP reserved
RV-6A Very Slow Build!
Reply With Quote
  #7  
Old 05-26-2014, 07:22 PM
David Paule David Paule is offline
 
Join Date: Dec 2009
Location: Boulder, CO
Posts: 4,435
Default

Dan, I saw your temp/humidity posting and thought that I'd share how I'm starting a simple Arduino project. Like you, I'm not an electronics expert. I'm an old retired stress engineer. This is new to me.

I ordered a Sparkfun Inventor's Kit for Arduino - V3.1 from Amazon for $100. They were out of them at Sparkfun locally (Sparkfun is a local company). Several other companies make starter kits. Mine should arrive Wednesday.

I downloaded the "IDE," or Interegrated Development Environment, the editor in which we will write our programs and upload them to the Arduino. I got that from http://www.arduino.cc/en/Main/Software.

There are numerous books and PDFs that you can get. The www.arduino.cc site has a language reference and the IDE and a starter's kit have examples.

When I get my gadget working I'll buy the Sparkfun Pro Mini, a tiny Arduino. https://www.sparkfun.com/products/11113. This will be the unit that I'll hardwire. This suggestion and the next item were recommended by the people at Sparkfun.

It needs a gadget to connect your computer to it, though, to upload the program. That's https://www.sparkfun.com/products/9716. It won't become a part of the flight system.

Other devices like sensors, resistors, switches, displays and so on, are usually also needed and are up to you.

Good luck!
Dave
Reply With Quote
  #8  
Old 05-26-2014, 07:43 PM
DanH's Avatar
DanH DanH is online now
 
Join Date: Oct 2005
Location: 08A
Posts: 9,500
Default

Quote:
If you can be a bit more specific in what you want to do the community can probably get you closer to a viable solution.
Thanks gentlemen. Don't mind a learning curve, but this time I'm looking for a quick approach.

App is determining the dew point of typical engine breather output, which can be derived from temperature and RH. That little sensor would slip right inside the hose and measure both at the same point.

Already have two temperature sensors in the lines. As expected, breather gas leaves the accessory case a bit warmer than oil temperature, and cools some as it passes through the separator. If separator outflow temperature is higher than dew point, water return to the engine case is not possible. One measurement is worth 1000 opinions, yes?
__________________
Dan Horton
RV-8 SS
Barrett IO-390
Reply With Quote
  #9  
Old 05-26-2014, 08:37 PM
PaigeHoffart PaigeHoffart is offline
 
Join Date: Jun 2005
Posts: 375
Default

I wonder if you'll run into issues with oil mist contaminating the sensor?

Look at page 14...

http://www.jma.go.jp/jma/jma-eng/jma...3-Humidity.pdf

Paige
Reply With Quote
  #10  
Old 05-26-2014, 08:42 PM
larosta larosta is offline
 
Join Date: Dec 2010
Location: Redlands, CA
Posts: 176
Default

Dan,

Take a look at this. You should be able to hook it up to a 4-5.8VDC power source and connect the output to your handheld voltmeter. Use a simple printed table to determine RH. The Sparkfun breakout board makes attaching the wires easier.

https://www.sparkfun.com/products/9569



The datasheet below has the conversion chart.

https://www.sparkfun.com/datasheets/...-datasheet.pdf


Here is a way to get the 5V from your aircraft power buss.

https://www.sparkfun.com/products/114


Phil

Last edited by larosta : 05-26-2014 at 08:49 PM. Reason: Added comment
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 06:33 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.