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Re: Arduino sampling speed

 by fusedlightning ¦  Wed Aug 21, 2013 6:16 am ¦  Forum: Arduino ¦  Topic: Arduino sampling speed ¦  Replies: 8 ¦  Views: 1541

Seems like there's two solutions being discussed: First, if you really want that analog signal, you can find a faster A/D converter, or even get multiple converters. Whether this is inside the processor, or an additional component, that's a design choice. Second, you can use some clever gaining and ...

Re: timer

 by fusedlightning ¦  Mon Aug 19, 2013 8:30 am ¦  Forum: Arduino ¦  Topic: timer ¦  Replies: 3 ¦  Views: 555

An interrupt would work, but for most applications I think this would be easier to implement by sticking to standard Arduino functions. Mee_n_Mac nailed it - using millis() or micros() to check the time on every loop and terminate if a target is exceeded may be the easiest way to approach the problem.

Re: Arduino sampling speed

 by fusedlightning ¦  Mon Aug 19, 2013 8:22 am ¦  Forum: Arduino ¦  Topic: Arduino sampling speed ¦  Replies: 8 ¦  Views: 1541

The analog-digital converter (ADC) on the Arduino, as configured by default, takes (nominally) 104 microseconds to complete. This conversion is what lets you record the voltage from the piezo sensor. This means that your sensor will only be sampled every 100us (roughly), and so your event time will ...

Re: LED Eye Safety

 by fusedlightning ¦  Mon Aug 12, 2013 12:23 pm ¦  Forum: SparkFun Product Questions ¦  Topic: LED Eye Safety ¦  Replies: 3 ¦  Views: 587

Skimask is correct. Dangerous light sources (UV, IR, Laser) carry warnings on them, because the individual is either unaware of damage occurring (UV/IR), or that the damage happens very quickly (Laser). There are other kinds of light sources that we think of as visible, but are still dangerous becau...

Re: Alternative Wifi adapter to RN-131C

 by fusedlightning ¦  Sat Aug 10, 2013 7:24 am ¦  Forum: Wireless/RF ¦  Topic: Alternative Wifi adapter to RN-131C ¦  Replies: 5 ¦  Views: 1090

Sorry you're having trouble. Big bright red text hurts my eyes, but here's what I know. Sometimes, these things take time to get working. It's great when devices are plug-and-play, but that isn't always the case. If you're looking for another wifi shield, a quick google search turned up many options...

Re: Impact measurement

 by fusedlightning ¦  Fri Aug 09, 2013 1:37 pm ¦  Forum: SparkFun Product Questions ¦  Topic: Impact measurement ¦  Replies: 10 ¦  Views: 975

Let's wait for the OP to get back to us on this one so we can know for sure what sort of solution fits this problem.

Re: Can I do this with an Arduino?

 by fusedlightning ¦  Fri Aug 09, 2013 1:23 pm ¦  Forum: Arduino ¦  Topic: Can I do this with an Arduino? ¦  Replies: 9 ¦  Views: 1224

Direct measurement is definitely possible. If you didn't want to use an Arduino, you could probably manage this with a 555 timer, a few caps and resistors, and an AND gate. Wouldn't be super precise, but would work well enough I think.

Re: Problems with ADC Troubleshooting

 by fusedlightning ¦  Fri Aug 09, 2013 11:06 am ¦  Forum: SparkFun Product Questions ¦  Topic: Problems with ADC Troubleshooting ¦  Replies: 10 ¦  Views: 1095

How accurate a result are you really looking to get? The LSB on a 12-bit bus scaled 0-2.5v (as I believe your situation is), is only 0.0006 volts (0.6mV!). Even if the ADC is scaled 0-5v, the LSB only represents 1.2mV. Is this kind of accuracy within the noise of your system? It's sounding more and ...

Re: Problems with ADC Troubleshooting

 by fusedlightning ¦  Fri Aug 09, 2013 9:27 am ¦  Forum: SparkFun Product Questions ¦  Topic: Problems with ADC Troubleshooting ¦  Replies: 10 ¦  Views: 1095

To make sure I understand what you said: 1) If you put 0V into the ADC, on some devices you get 0b000000000000 out, and others you get 0b000000000001 out. 2) As you increase the voltage from 0V to 2.5V, you see the LSB flip repeatedly between 0 and 1. 3) If you stop the voltage increase, the LSB sta...

Re: Impact measurement

 by fusedlightning ¦  Fri Aug 09, 2013 9:22 am ¦  Forum: SparkFun Product Questions ¦  Topic: Impact measurement ¦  Replies: 10 ¦  Views: 975

Lyndon, Knowing the acceleration of the spring, and knowing the forces acting on it are very different! If the spring were a single, rigid body, you are entirely correct that slapping an accelerometer on it and calculating its acceleration can give you information about the net force acting on it (w...

Re: Can I do this with an Arduino?

 by fusedlightning ¦  Fri Aug 09, 2013 7:00 am ¦  Forum: Arduino ¦  Topic: Can I do this with an Arduino? ¦  Replies: 9 ¦  Views: 1224

I agree with Skimask - some sort of beam-break would be a great way to handle it. You will have to make a decision with a beam break about how little motion "stopped" is. That'll dictate how close to the rest position your beam(s) will need to be. There's an example here that shows an example of thi...

Re: Position of a smart phone accurate to a meter and indoor

 by fusedlightning ¦  Thu Aug 08, 2013 9:31 pm ¦  Forum: SparkFun Product Questions ¦  Topic: Position of a smart phone accurate to a meter and indoors ¦  Replies: 11 ¦  Views: 1787

To be clear with Mee_n_Mac's post, you would not be able to use RTK GPS with the GPS module inside any (that I know of) commercial smartphone. It would need to be added as an exterior module and interfaced.

Re: using AVRisp mkii with Crosspack Avr-dude

 by fusedlightning ¦  Thu Aug 08, 2013 9:28 pm ¦  Forum: AVR Microcontrollers ¦  Topic: using AVRisp mkii with Crosspack Avr-dude ¦  Replies: 3 ¦  Views: 1694

Since this is dug up again, for anyone interested, the question was answered over on avrfreaks.net here!

Re: Problems with ADC Troubleshooting

 by fusedlightning ¦  Thu Aug 08, 2013 9:22 pm ¦  Forum: SparkFun Product Questions ¦  Topic: Problems with ADC Troubleshooting ¦  Replies: 10 ¦  Views: 1095

Another question - in your original statement, it seemed unclear if the LSB would -ever- go low. If you put a nonzero voltage on, will you see the LSB go through transitions? If the LSB's completely stuck high, that definitely sounds like a hardware problem. However, if the LSB simply won't go low a...

Re: Impact measurement

 by fusedlightning ¦  Thu Aug 08, 2013 9:18 pm ¦  Forum: SparkFun Product Questions ¦  Topic: Impact measurement ¦  Replies: 10 ¦  Views: 975

Okay, there's a couple different ways to go with this. First, the parts definitely exist. Sparkfun sells a few different accelerometers, and I'm sure one of them will be able to do what you want (though be careful, an accelerometer by itself doesn't necessarily give you "Google maps location")! Now,...