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1  Using Arduino / Project Guidance / Re: Is 12V to 5V conversion possible while maintaining ratios? on: August 17, 2014, 08:51:56 pm
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  And yes, I believe I am looking to assign a digital count value in the range 0-1023, but applied to 12V instead of 5V 

Then what you are calling a  12V to 5V converter,  is the voltage divider mentioned in last post by RogerClark.
The values you need are 5.6 k ohm and 4.2 k ohm with the 5.6 k ohm resistor connected to the 12 signal and the 4.2 k resistor connected to ground. The point where the two resistors connect is where you obtain  your analog 0 to 5 V output.


FYI, after the fact, for future reference. the question you were asking here :
Quote
  Is it possible to or is there a device that can convert a 0-12V input to 0-5V input so that it's usable to the arduino? There is something I would like the Arduino to measure but it varies between 0V and 12V.
 

can be correctly stated as follows:
Quote
I would like to scale a 12V analog signal down to 5V. How do I do that ?
(hence the name "voltage divider ")

That is a much simpler way to state what I was looking for. I'm sorry for being so misleading or confusing smiley-confuse, and thank for clearing that up for me smiley.

Surely you just need a voltage divider .i.e 2 resistors in series, with the midpoint connected to the Analog input

See https://en.wikipedia.org/wiki/Voltage_divider



I don't know why I completely forgot about this....the first thing I learned in EET. Shame on me.

Thanks again guys, I really appreciate the help! smiley-lol
2  Using Arduino / Project Guidance / Re: Is 12V to 5V conversion possible while maintaining ratios? on: August 17, 2014, 08:35:17 pm
No I wasn't try to be rude or belittle you but you clearly stated here:

Quote
Is it possible to or is there a device that can convert a 0-12V input to 0-5V input so that it's usable to the arduino?] Is it possible to or is there a device that can convert a 0-12V input to 0-5V input so that it's usable to the arduino? 

which means you are interested in converting some signal to 0's or 1's. This is what the above question is saying . If that is not what you want and you have multiple states (in order to be BINARY , it MUST be TWO STATES and ONLY TWO STATES. (0 AND 1).
State your intentions:
DIGITAL BINARY , or MULTIPLE STATES.

The Arduino can take an analog input from 0-5V and assign it a digital count value between 0-1023. I would like it to be able to do this with an input from 0-12V. I'm not sure if this means that I'm looking for digital binary or multiple states honestly.
3  Using Arduino / Project Guidance / Re: Is 12V to 5V conversion possible while maintaining ratios? on: August 17, 2014, 08:15:41 pm
Quote

ha , ha , ha,
No kidding ? That's why it's called an Analog to Digital Converter.  What you are talking about might require a different approach. Your objective does not appear to be a digital count value in the range 0-1023. If it were , you wouldn't be posting for this question.

I can't tell if you're trying to come off rude or not, but keep in mind that I'm at your mercy and coming here for help, not to be belittled. And yes, I believe I am looking to assign a digital count value in the range 0-1023, but applied to 12V instead of 5V levels.

Quote
  Is it possible to or is there a device that can convert a 0-12V input to 0-5V input so that it's usable to the arduino? There is something I would like the Arduino to measure but it varies between 0V and 12V. 

Asking a question about a specific solution using "vague"  or cryptic wording like :
Quote
  There is something I would like the Arduino to measure but it varies between 0V and 12V.   
is not going to help much. Is there some reason why you can't tell us what it is you want to measure ? You want us to help you but you are omitting something we need to know. Is that intentional or unintentional ?

I'm sorry, I was just trying to keep it simple.

Automotive stereos with Steering Wheel Control (SWC) capability typically operate in one of two major "styles" or "methods". There is the older style typically referred to as "Analog" in which a resistor network or voltage divider is created between the steering wheel's buttons and slip ring. This different voltage or resistance value is passed on to the radio via a wired connection. The radio then "interprets" the different voltage/resistance values as commands. The "Digital" style typically uses CAN-BUS communication which is typically serial data communication using +/-5V or +/-12V pulses.

I did a little research and found out that my car uses "analog" SWC. I'm not sure yet whether it rests at 5V (preferable) or 12V. If it rests at 12V I would like to be able to read the voltage it's pulled down to and store it to memory so that I can then use these voltage levels as triggers for independent outputs.

I can get into more detail about the outputs if you'd like, but I think it's irrelevant to the first portion of my task at hand.
4  Using Arduino / Project Guidance / Re: Is 12V to 5V conversion possible while maintaining ratios? on: August 17, 2014, 07:41:02 pm
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The Arduino (UNO's) analog input can convert an analog signal into a digital signal 

Really ? Why don't you post some code demonstrating how you would do this ?

It's a built in function:http://arduino.cc/en/Tutorial/AnalogInput

Also, I meant to say "value" instead of signal. My apologies.
5  Using Arduino / Project Guidance / Is 12V to 5V conversion possible while maintaining ratios? on: August 17, 2014, 07:31:54 pm
I'm not quite sure how to explain what I'm looking for, but I'l try anyway.

The Arduino (UNO's) analog input can convert an analog signal into a digital signal. However, I see that it's limitation is that it's anywhere from 0-5V.

3.5V is 70% of 5V, therefore the digital equivalent would be somewhere close to 716 (in a range of 0 to 1023).
The 70% equivalent to 12V would be 8.4V. If I were able to map 12V to 5V the digital equivalent would also be 716.

Is it possible to or is there a device that can convert a 0-12V input to 0-5V input so that it's usable to the arduino? There is something I would like the Arduino to measure but it varies between 0V and 12V.

I hope I've explained myself well enough.
Thanks in advance!

-Miguel
6  Using Arduino / Project Guidance / Re: Where to find a custom usb flash memory drive or have one made? on: January 08, 2014, 07:31:58 pm
http://www.trustedreviews.com/news/Lexar-Memory-Key-Adds-Storage-Gauge

I do not know if the patent is so broad as to cover "visual" to include LCD and LED, etc.

Ray

Wow, pretty cool. That's the one they came out with in '06. This is they're latest and greatest : http://www.lexar.com/products/lexar-jumpdrive-m10-secure-usb3-flash-drive?category=207
7  Using Arduino / Project Guidance / Re: Where to find a custom usb flash memory drive or have one made? on: January 08, 2014, 09:08:12 am
The obvious approach would be to put something between the flash storage and the external interface that passed I/O requests through and added the capacity monitoring/display logic. There would be quite a lot of work to do, because it'd need to understand the file system as well as the I/O protocol, and USB is complicated in its own right. I suspect that the simple approaches to achieve that would cripple the throughput, too.

I watched a presentation recently from a team that had reverse-engineered some SD storage cards and discovered that they contained programmable microcontrollers to do the storage management and error correction. Figuring out how to reprogram the controller without support from the manufacturer seemed like a really tough challenge, and I think there was still a lot of work to do to figure out the instruction set and architecture and so on, but they had got as far as uploading their own code and using it to control I/O pins to turn LEDs on and off. I think you'd need to solve all that in order to embed the logic into the storage device itself, and unless you're working with the manufacturer it would be extremely difficult. I expect the same would hold for other flash devices such as USB sticks. It's only a matter of time before somebody cracks all that, though, and then I don't see why it would be any more complicated than programming an Arduino.



The more I look into this the more daunting it seems. Sure would be nice to be able to interface with though.
8  Using Arduino / Project Guidance / Re: Safest way to switch 110V AC on/off on: January 06, 2014, 03:45:37 pm
Powertail is good, or you could also use something called a Solid State Relay. It's controlled off of a 5VDC potential with a small enough current draw to be able to be used directly off a microcontroller.
9  Using Arduino / Project Guidance / Re: Where to find a custom usb flash memory drive or have one made? on: January 06, 2014, 01:56:58 pm
Look at what's in a USB drive
http://en.wikipedia.org/wiki/USB_flash_drive
There are several pics of the internals.

I was just checking that out, hah!
10  Using Arduino / Project Guidance / Re: Where to find a custom usb flash memory drive or have one made? on: January 06, 2014, 01:30:50 pm
So you really need something like this
http://www.saelig.com/EL/ICSDSDIO001.htm
Provides the PC/USB connection to the memory device.
Add some circuitry to let a microcontroller control the chip as well so you run your own query on memory usage (# of files, size, do the math & light the LED).
Not for the faint of heart.

Definitely not for the faint of heart. But at least I have some direction so thank you for that!

Anyone else have experience or any other ideas/recommendations?
11  Using Arduino / Project Guidance / Re: Where to find a custom usb flash memory drive or have one made? on: January 06, 2014, 01:05:50 pm
So a flash drive with an Atmega 8U2 basically that you can send messages as to which color to light up. Otherwise, the controller has to monitor all traffic and recognize the file format, how big files are, when they are added/deleted, sounds like a nightmare to code.

I'd probably end up having to go the ways of kickstarter for this or finding a software engineer who's up for a challenge. Granted, I don't know code as well as a programmer but I guess to make it easier it could be designed/programmed to check memory upon bootup/connection, not necessarily during reading/writing.
12  Using Arduino / Project Guidance / Where to find a custom usb flash memory drive or have one made? on: January 06, 2014, 12:46:27 pm
Hey everyone,

I have a project in mind that involves a usb memory stick. In the end I would like a flash drive (exterior casing not needed) that with an RGB LED on the end of it.

Right now all I've done is soldered a resistor and LED onto the VCC and GND pins  (1 & 4) on the USB connector. This lights up the LED constantly as long as it's plugged in. I would like to control when and how it lights up.

Ultimately my goal is to program the flash drive so that the LED responds to the drive's memory capacity. For example blue or green when empty, yellow when it's halfway, and red or flashing red towards max capacity. Once that's done there's a case that I would like to build around it so that the LED's light radiates through it and makes the whole case glow.

Are there any companies out there that can or already build custom flash drives with programmable IC's? I would like to be able to program the on-board IC to control the LED's behavior without it affecting the flash memory. This way the end-user can't accidentally corrupt the firmware controlling the LED.

I hope that made sense. Thanks in advance!
13  Using Arduino / General Electronics / Re: How can I replace this relay with a MOSFET? on: November 12, 2013, 07:21:49 pm
Thanks again for the help.

I decided to redraw my schematic to account for a solid state relay. Now the light should only turn on when both the rocker switch is on and the reed switch is on (door open).

What I'm doing is mounting a light and using the relay to interrupt or source power to it while maintaining the rocker switch built into the housing. This will let me cut power to it preventing the light from turning on in case I need to leave the door open for a long period of time, like when I air out the house.
14  Using Arduino / General Electronics / Re: How can I replace this relay with a MOSFET? on: November 12, 2013, 03:53:23 pm
Good to know. Thank you so much!
15  Using Arduino / General Electronics / Re: How can I replace this relay with a MOSFET? on: November 12, 2013, 03:47:01 pm
I can't believe I completely forgot about solid state relays lol. Thanks jremington!

Why wouldn't I be able to use MOSFETs for something like this?
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