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Community / Products and Services / Re: Square Inch PCB from Electronic Interconnect.
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on: April 16, 2013, 05:43:55 pm
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$3 per square inch is that for 1 or a 100 boards??
I agree that having to create an account to see the prices or post a message here about how good are prices are without a decent disclosure as to what their prices are. You have heard from any number of people that are not happy to create an account to see your prices. Claiming to have over 3000 happy customers in response to customers that are not happy with your hidden pricing information is not being very customer friendly.
I do not understand hiding your prices on an instant quote system as any of the competitors could easily use a throw away email account and get your prices easily.
I am always suspicious at comapanies that are not proud enough of their pricing to advertise up front and out loud, it sounds like I am not the only one. In today's information age we have all been conditioned to instant gratification in terms of pricing and I think the vendors who realize this will prosper on the bones of those who don't.
wade
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Using Arduino / General Electronics / Re: altitude detector
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on: April 05, 2013, 11:08:32 am
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If all you want is relative difference in altitude between your location and some other location, say a low-altitude weather balloon, you can use a MPL115A2 on the balloon and one at your location and the difference in atmospheric pressures will tell you the difference in height. Using the differential pressure method reduces the effects changes in the weather, note I said reduces the effects not eliminates. After working on systems like this I can tell you the baro method of height estimation will be more accurate then the GPS method in the majority of cases.
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Using Arduino / Project Guidance / Re: Building a Spring Tester
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on: March 22, 2013, 09:48:42 am
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Have you thought of interfacing to a digital linear scale to make the linear measurements of the spring position? There are quite a few web pages that discuss interfacing an Arduino to linear scales, I have not checked whether they have the requisite resolution.
To get the required motion you could use a linear actuator rated for the force required and use the arduino interfaced to a motor control board.
Free advice and worth every cent!
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Using Arduino / Sensors / Re: Sound Sensor
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on: March 02, 2013, 01:53:37 pm
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I think you could build a small sensor board that would trigger an alarm based simply upon the volume. The false alarm rate would probably be very low given that the ambient noise level in the kennel probably rarely gets to a volume close to that of the dog barking. I do not think you need a noise canceling system given the relative volumes.
You could set up the sound sensor to light an LED and monitor it to see if you have a false alarm problem so as not to confuse the dogs. Running just the LED with the sensor would also be required so you could set the threshold at a level to ignore ambient but trigger on barking. A filter on the sound sensor based on frequency could further reduce the false alarm rate.
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Using Arduino / Sensors / Re: Self-Levelling with MPU 6050 and 2 servos
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on: March 02, 2013, 11:55:36 am
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Search this site directly or Google the world and you will find places to start and then you can help us by asking direct questions about aspects that you do not understand. Starting out with the broad type of question like you have will neither help you or us.
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Using Arduino / Project Guidance / Re: arduino +100Mhz radio jammer
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on: February 23, 2013, 03:19:11 pm
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I am getting great chuckles that anyone over the age of 10 years of age would except what is said on any Wiki page when it comes to laws. I do not think the I read on Wiki-XYZ would be a very strong defense, at least not strong enough to bet on.
But hey go for it! You could be setting precedents and if not you may get to meet a bunch of people that you normally don't in your normal walks of life.
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Using Arduino / Project Guidance / Re: Senior Project (Kickstart)
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on: February 22, 2013, 11:24:26 am
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I worked as the technical director for the Desert Hawk UAV product while at lockheed and one of the difficult problems for small UAVs is an accurate altitude solution. Actually I should say the height above ground mainly when coming in for a landing, if you have an altitude that is accurate within say 10 feet you can localize your landing much better and reduce damage also from landing.
People have thought of laser range finders but they are a hard nit to crack given the timing and expense of the APD. Radar is a possibility as is differential baro altimeters, the GPS vertical error is too high to work for this app. The differential baro would entail putting one of the high accuracy MEMS baro on the bird and one on the groundstation. The mission time is too long for you to rely on the original baro reading that you took off with so as you approach for landing you send the current baro at ground level in the landing area to the bird. The height above ground is a simple calculation based on the difference in baro readings, thus the term differential baro.
Building a small radar altimeter may be a better approach as then you do not need any changes to the ground station and is a little sexier than measuring the air pressure. The folks over at DIYDrones may help you on test flights if you share some of your completed hardware, trust me that is very cheap flight testing.
wade
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Using Arduino / Project Guidance / Re: Temperture/humidity sensor ?
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on: February 19, 2013, 11:06:33 am
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Do you really need to measure the humidity to a resolution of 0.1%, I ask because if you do absolutely do the sensor is going to cost you a lot of money. Maybe you could tell us what you are using the measurements for we may be able to help you on your requirements.
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