Show Posts
Pages: [1] 2 3 ... 10
1  Using Arduino / Project Guidance / Re: Expressions used with Rotary Encoders on: August 13, 2014, 11:12:51 am
Well I can only partially help.  The first thing to know is there are different types of rotary encoders.  They do not all work the same way.  The most common rotary encoder are sometimes called "gray code" encoders.  They have 2 pins that are pulsed based on which direction you turn the encoder.  If you turn it one way, the pin for that direction pulses for each step it is turned.  If you turn it the opposite direction, the other pin pulses for each step in the turn in that direction.  Your micro has to count the pulses from both pins and increment or decrement some variable accordingly.  Steps per revolution refers to how many pulses you get in one complete 360 degree rotation of the encoder.  So a 16 step encoder has 16 steps in one 360 degree rotation and a 48 step encoder has 48 steps (just to name 2 examples).

There are other types of encoders that actually output values by using different combinations of highs and lows across multiple pins.  There are encoders that count in hexadecimal, octal, binary, etc.  The datasheets for these usually have a table that shows you what value corresponds to each combination of pins.  There are usually more pins on these kinds of encoders. 
2  Using Arduino / Project Guidance / Re: New Project Help on: August 13, 2014, 10:57:27 am
Sorry to hear about your mom.  I recommend doing a search here and on the Internet... this is a question that has come up at lot.  One thing you're missing from your kit:  You'll probably need some optoisolated relays that handle a decent amount of current and amps.  You'll need these to switch on the generator and to engage and release the starter.  I'd recommend the 4-relay module from Sainsmart because it's only about $10 and it already has optoisolators on it and the relay contacts are rated for 125VAC and 30VDC at 15 amps.
3  Using Arduino / Project Guidance / Re: RC car hack on: August 13, 2014, 10:48:19 am
One problem is that if you measure the voltage across the transmitter pots it is probably 9V.  In order to use a digital pot you would need to find a digital pot that can operate at that voltage. Otherwise you will have to use RC servos to move the gimble sticks. or turn the pot shafts. That is the first thing you need to do. If you cannot control the stick position with an RC servo then I don't know how to hack it.
If you can get that part working the rest is fairly straight forward. Use the Servo Library to control the RC servos.

Probably a moot point since the transmitter in this case has no pots... but I have looked at several RC toy transmitters and the voltage on the pots was not 9V but 5V on the ones I looked at.  All the ones I've messed with had voltage regulators on them.  Cheap ones that look just like regular transistors and have no heat sinks of any kind.  I've even seen one that had 3 of them.
4  Using Arduino / Project Guidance / Re: What products do I need to order? on: August 13, 2014, 10:37:35 am
I could be wrong, but it sounds like you are trying to make a "war" machine to map out devices in range... for what purpose I wonder?
5  Using Arduino / Project Guidance / Re: Designing A Laser Tag System : IR Problems on: August 12, 2014, 10:44:34 am
So is this game being played in the dark or during bright, sunny days?  The reason I ask is sunlight has a lot of IR in it and can blind your IR detectors.
6  Using Arduino / Project Guidance / Re: Attiny85 led die. on: August 12, 2014, 10:20:41 am
Maybe you could make one with a ball bearing (that conducts), some wire, and a small section of straw.  Put both wires in one end of the straw so that when the ball comes in contact with them, it conducts.
7  Using Arduino / Project Guidance / Re: Remote Control Boat on: August 08, 2014, 01:39:45 pm
i have a lot of experience in this area.  I built a transmitter with an Arduino in it.  I started by hacking an existing HobbyKing 6 channel 2.4Ghz transmitter.  Originally the Arduino controlled the analog inputs to the transmitter board via digital potentiometer chips that worked off the i2c bus.  Worked great until one day the HobbyKing transmitter board went bad.  The 2.4Ghz radio module was still good, however, I learned that I could output PPM directly to the radio module using a single I/O pin.  The end result is this:

https://www.youtube.com/watch?v=4gAW0vQ24z8

https://www.youtube.com/watch?v=IWUb9n27gLk

And here's a long build thread with lots of pictures, video, and iterations leading up to the final result:
http://www.rcgroups.com/forums/showthread.php?t=1800914
8  Using Arduino / Project Guidance / Re: Read car AC display using Arduino on: July 23, 2014, 10:19:48 am
Careful!  You are doing things that can damage your Arduino!

The acc wire that supplies 12V... yes, it could be used to power the Arduino, but you should be aware that it can be a "noisy" 12 volts and might have voltage drops or voltage spikes.  Others have written about this.  Not sure what the best advice is for this, but in theory it should work.  I think I've read of others putting a voltage regulator in between the 12V and the Arduino to help save the Arduino from battery weirdness.

Using a 5V voltage regulator to drop a 12V signal for sense detection on an Arduino is not a good idea.  It is a really, really bad idea.  You should not do that.  What you should do is use an optoisolator as a switch.  Have the 12V signal switch the optoisolator on/off.  Have a digital I/O pin on the Arduino connected to ground on the Arduino.  So when the 12V signal is there, the switch is on, and current flows from the digital I/O pin to ground.  When the 12V signal is not there, no current flows from the digital I/O pin to ground.  Your use of a voltage regulator is just plain wrong.  You do not want to add voltage to an Arduino's input pins from another voltage source.  They aren't designed to do that.  A voltage regulator will generate heat by burning off the excess voltage as... well... heat.  It is designed to power something - not for using as an input signal.  It might work, but it also might fry your Arduino.

The analog pins on the Arduino are only designed for 0 to 5V.  The value you are getting is NOT voltage.  The value is a range between 0 and 1023, which corresponds to 0 to 5V.  So if you read a value of 512, that would be approximately 2.5V.

As for what you suspect is a data wire...  It's not likely to be a compatible serial signal that you can just hook up to the serial pins on an Arduino.  You would need an oscilliscope or a digital probe that actually capture and analyze the highs and lows to figure out the signaling and protocol.  Not something you can do without one, unless you can somehow find the specs on the protocol used.  And even if it was a TTL serial or RS-232 or RS-485 signal, tapping into it with an Arduino could affect the signal and make it not work.

Is the fan knob a potentiometer with 3 wires?  If so, your  best bet might be to disconnect the fan knob from the AC unit and instead connect it to the Arduino to read, then use a digital potentiometer IC (like the DS1308 for example) to send a digitally controlled output to the AC unit.  This would also let you override the fan setting from the Arduino.
9  Using Arduino / Project Guidance / Re: How to drive lights with a text file on: July 14, 2014, 12:35:13 pm
You mentioned "Word document", which I take to mean Microsoft Word.  You're not going to get an Arduino to read that.  You will want to use a plain text file, aka ascii file.  How do you intend to "feed" the file to the Arduino?  SD card?
10  Using Arduino / Project Guidance / Re: custom PCB on: July 14, 2014, 12:31:07 pm
Some advice for the "tombstoning"...  (By the way, I assume you meant 0603, or 0805, not 0803).  Are you sure you are putting down the right amount of paste?  Too little can cause problems.  Are you putting down paste unevenly --meaning 1 pad has way more paste than the other pad?  That's where most of my tombstoning happens.  I personally don't use an oven - I do all my surface mounts with a hot air reworking station.  Uneven heating can lead to tombstoning too, so maybe take a look at how your oven is heating the boards?  Finally... there is a glue you can use to hold the parts in place.  I forget what it's called, but it's usually reddish in color.  I've never used it, but one little tiny tab of that between the pads will hold your resistors and caps in place and prevent the tombstoning during reflow.
11  Using Arduino / Project Guidance / Re: Help design a system on: July 02, 2014, 01:43:00 pm
I can't remember whether it's from one of the Iron Man movies or RoboCop, but I remember a scene when they were demonstrating a suit and it malfunctioned, ripping the driver's lower torso off and kill him.  Think that was Iron Man.

EDIT:  It was from IronMan 2.  Oh yeah, and according Justin Hammer, the test pilot survived.  Lol.
12  Using Arduino / Project Guidance / Re: does anyone know what kind of sensor is used in this application? on: June 23, 2014, 12:40:40 pm
Didn't you already post about this a few weeks ago, or was that some other person?  The sensor in the first photo is an untrasonic distance sensor, also commonly called a "ping" sensor.  It literally "chirps" an ultrasonic pulse out of one of the cans.  In theory, the pulse echos off an obstruction and is received back to the other can.  You typically count how long it takes for the pulse to come back, and from there it is a simple mathematical formula to calculate the distance.  These are commonly used for robots to help with collision avoidance or for anything where you want to attempt to measure the distance from something.  I've got some experience with them.  I don't think they will be a good sensor for you to use on your hoop machine.  First, they are prone to errors...  The sound radiates outward and pulses can be echoed off a wide range of things... the further out the pulse goes, the bigger the chance the pulse will echo off something not directly in front.  For example, I attempted to build a parking assistant for my garage.  The pulses were constantly bouncing off other things in my garage causing false distances.  Also, these don't work well if the surface they hit is curved or angled away.  They work best with the object they hit is flat and directly facing the sensor.  Case in point, my wife's car has a lot of curves on the front of it.  I could never get the sensor to report correct distances with her car, yet it worked fine with my car.

As I mentioned in the other thread, the best way to do this is with an IR proximity detector or IR break beam.  If you had it mounted just under the rim angled at a downward angle, this would probably eliminate false triggers.  The idea is there is an IR emitter that shoots infrared light that gets reflected back only if a ball is in the way.  Since the beam won't be reflected back until the ball is more than halfway in, you should be able to prove the ball is going through.  You're probably going to have to adjust the angle until you get it right.

Give this one a try:
http://www.pololu.com/product/1134

Or this one:
http://www.pololu.com/product/2464

13  Using Arduino / Project Guidance / Re: Counting Person entering a room on: June 23, 2014, 10:17:10 am
That's great that it works.  I guess either you've set the RSTDISBL bit to disable reset on PC6 or you're just lucky with PC6 floating.  I guess one way you could test that is to touch a wire between PC6 and GND for a few seconds and see if it resets.  Since this pin isn't connected to anything, you have a floating pin.  If you have not set the RSTDISBL bit, your chip could periodically reset itself.  Heck, it might be doing that right now without you even realizing it depending on how your sketch works.
14  Using Arduino / Project Guidance / Re: Another Orbit Yard Watering valve question. on: June 20, 2014, 02:52:03 pm
All my Orbit sprinkler valves are "jar-top" solenoid valves.  If I'm not mistaken, these valves are closed if no electrical current flows, and they open when power is applied.  Power in this case is low-voltage AC, I think 24 volts.   
15  Using Arduino / Project Guidance / Re: Counting Person entering a room on: June 20, 2014, 12:15:22 pm
You're also missing a pullup resistor on the reset line.  Without that, the chip will be stuck in reset mode.  Also, how are you going to program the chip?  Recommend you put in ICSP interface or at least breakout the RX/TX and reset pins so you can use a FTDI USB to serial interface to program an already boot-loaded chip.  Question... have you actually tried this circuit out on a breadboard to prove it works?  I'm guessing no, because there are a lot of things wrong with it.  Breadboard it first before you design your PCB.  Will help you figure out some mistakes.
Pages: [1] 2 3 ... 10