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226  Using Arduino / Project Guidance / Re: Lithium Battery Management System on: September 18, 2013, 12:27:12 am
Heres an IC specifically designed for managing 12 series LIPO batteries for the EV market.
http://www.intersil.com/content/dam/Intersil/documents/isl7/isl78600.01_product_brief_hr.pdf
If you really want to do this , then its best to use electronics specifically designed for the purpose.
Theres a lot of energy in a series LIPO battery string, and you sure dont want anything to go wrong.
As Grumpy_Mike has indicated, this is not a beginners project.
227  Using Arduino / Project Guidance / Re: Lithium Battery Management System on: September 17, 2013, 04:29:27 am
Your question is a bit vague.
If you are going to have 11 battery packs in series , why do you just want to measure one of them.
You will need to measure them all , and thats a far bigger exercise than just measuring one.
Can you explain a bit more about the project.
228  Using Arduino / Sensors / Re: Wind Speed and Direction Sensor on: September 15, 2013, 12:52:26 am
Be careful buying el cheapo anemometers off the net .
Many will not come with any calibration data which means that you wont know what the relationship between spin rate and the wind speed actually is.
229  Using Arduino / General Electronics / Re: CT Clamp and AC to DC on: September 15, 2013, 12:45:16 am
How accurate do you want the result to be?
CT type power measurements arnt very accurate because they assume the supply voltage never varies
which is almost never the case.
230  Using Arduino / Motors, Mechanics, and Power / Re: Can 12v 100mA solar panel run the Arduino and one question about Li-Ion battery on: September 13, 2013, 08:08:13 pm
In order to make a project like this work off Solar, its critical that you know the maximum daily total energy consumption.
So you need to determine how much power the Arduino uses and how much power the water pump will use per day.
Based on that its possible to determine whether the Solar panels are sufficient or not.
The water pump will most likley be the biggest energy consumer.

With any kind of Solar powered project, sizing the Solar Panels is the last thing you do after determining the projects total daily
energy consumption.

231  Using Arduino / General Electronics / Re: Voltage regulator help on: September 13, 2013, 07:15:48 pm
Buck converters are strange things to many people.
Heres a good simple explanation of how they work.
http://www.ecircuitcenter.com/Circuits/smps_buck/smps_buck.htm

And yes, the Inductor is a critical part of the converter.
So is the catch diode which you cant see because its inside the IC
232  Using Arduino / Sensors / Re: is there anyway to make smaller antenna for FPV system ? on: September 13, 2013, 04:18:07 am
Its not possible to make the antenna smaller without adversly affecting the range.
Depends on how far you want to transmit.
233  Using Arduino / Motors, Mechanics, and Power / Re: Induction Motor Control through PWN of arduino on: September 07, 2013, 07:28:55 am
Not possible with PWM.
You can vary the speed of a 3 phase induction motor with a VFD (variable speed drive) that you control with the Arduino.
If its a single phase capacitor start induction motor, you cant vary the speed at all.
234  Using Arduino / Networking, Protocols, and Devices / Re: 433 RF question. on: September 05, 2013, 06:20:16 pm
If you dont want to use 2 mcus, its possible to use dedicated hardware such as SC2262,SC2272 encoder / decoder chips
with those radios to send simple 4 bit logic states from one location to another.
This method is designed for applications where a simple button press is all thats needed, and the decoding process is slow.
Can take a few 100 ms to decode the data.

235  Using Arduino / Networking, Protocols, and Devices / Re: 433 RF question. on: September 05, 2013, 08:26:36 am
Those cheap 433 Mhz radio modules wont simulate a hard wired connection, so you cant easily send serial data thru them without some kind
of data processing, which is what The Virtualwire library does.
236  Using Arduino / Project Guidance / Re: RF 433mhz. Missing antenna? (lots of junk receiving) on: September 01, 2013, 05:38:51 pm
There are 2 types , normal superhets and super regenns.
Its hard to tell from looking at them which they are , but yes, the super regens do radiate quite a bit and can interfere
with other receivers in the vicinity.
237  Using Arduino / Project Guidance / Re: Hacking devices with Saw resonators instead if IR transmitters on: August 31, 2013, 12:38:57 am
That video shows an Arduino transmitting  using a 433 Mhz ASK Transmitter.
The Transmitter has a SAW resonator on it , to determine the frequency, usually 433.92 Mhz
but it also has additional electronics on the same little board to actually generate the RF.
The SAW resonator only sets the frequency.
A SAW resonator by itself does nothing.
238  Using Arduino / General Electronics / Re: Bluetooth and Arduino Electromagnetic interference question on: August 30, 2013, 08:59:49 pm
Is the whistle you are hearing around 1.6 Khz.
If so, this is the chirp rate that Bluetooth uses, and it will be the same for any Bluetooth device.
Blueetooth uses  frequency hopping technology which means that the 2.4 Ghz transmitter is pulsing on and off at the
chirp rate.
239  Using Arduino / Project Guidance / Re: Hacking devices with Saw resonators instead if IR transmitters on: August 30, 2013, 08:54:43 pm
Bit of confusion here.
A SAW resonator is a passive device that looks like a high Q frequency determining network.
It behaves in a way similar to a crystal, but can work at much higher frequencies.
A SAW resonator doesnt create RF , you still need extra electronics to do that.
240  Using Arduino / Sensors / Re: DHT11 and humidty, whats the extent of the problem? on: August 29, 2013, 06:27:26 pm
There are accurate humidity sensors.
Here is one.
http://www.sensirion.com/en/products/humidity-temperature/humidity-sensor-sht25/
They are not cheap though, $50+.
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