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1  Using Arduino / General Electronics / Re: Battery Monitoring System for Arduino on: September 17, 2014, 11:29:32 am
(btw, fully charged two cells battery is 7.4V at maximum, not 8.4 as reported above)

3.7V is the nominal, per-cell voltage. Fully charged is 4.2V.
2  Topics / Robotics / Re: Power options and servos on: September 17, 2014, 09:36:57 am
18650 batteries are a bit larger than AA; about 1/3rd thicker and longer. You will need a special charger for them.

But to answer your question either the 2x18650/3.7V or 2x4AA should work well.
3  Using Arduino / General Electronics / Re: Battery Monitoring System for Arduino on: September 16, 2014, 02:37:59 pm
A two cell lithium battery will vary between 8.4V (fully charged) and 6.8V.

If you have an LM3914 then you don't need anything else. Are you just trying to create the LED bar graph or are you trying to do something more than that?
4  Products / Arduino Yún / Re: SSH over ssh on: September 12, 2014, 05:55:54 am
I'm not quite quite sure why/if you're trying to make some kind of issue out of my initial description re colour?
It is a well recognized term..
"Vehicle" is a well-recognized term also. But you don't go to your mechanic with the expectation that he doesn't care what kind of vehicle you have, do you? Do you get obstinate when he asks for more detail and start providing Wikipedia links or try to placate him with a statement like "Well, it's an old truck"?


And, as I've said in other  posts, I'm a linux newbie, so while I'll happily type in  "ifconfig -a" or  "netstat -rn" into my yun, could you tell me what I'm doing, or trying to do ?

The ethernet interface needs to have an IP configured on it manually as, by default, it attempts to get an IP from the device it's attached to using DHCP. "ifconfig -a" shows the current state of the WiFi and ethernet port. "netstat -rn" shows the current network routing. Not only do you need to set an IP on your ethernet port you also need to ensure that connections to the media device will be routed through that ethernet port.

I think your problem can be solved by executing:
ifconfig eth1 netmask
This command should also automatically add a route for for that ethernet port.

Perform a "ping" to test to see if the connection works. Using SSH to test an ethernet connection can be unreliable -- notably a lack of DNS availability by the destination host can cause a long lag in the connection time. If the ping works then exercise patience when testing the SSH connection.

If nothing works, then again, provide the netstat and ifconfig output. Also, you may need a crossover ethernet cable between the Yun and media device. If the media device has a "link" light on the ethernet port then pay attention to see if it lights up when the cable is plugged in.

As an aside, is a publicly addressable address range. is typically used for a private network. You might already be aware of that, but just pointing it out.
5  Using Arduino / Project Guidance / Re: Autogravure Project on: September 11, 2014, 10:50:54 am
So it sounds like you're planning on sending bit strings ~32 bits in length from the computer to the Arduino, then on the Arduino just use a simple sketch to push those bits onto the Arduino pins.

You'll want to look at Port Manipulation; I guess it would be akin to directly accessing the I/O buffers in Windows; with very little overhead you can push a byte onto an AVR register to set the output state of 8 pins. See also,25799.0.html for a couple links to references for the port-to-pin groupings for the Arduino Mega.

Be sure to avoid PORTD as that port contains the TX/RX pins (pins 0 and 1) that the USB-to-serial translator on the Arduino uses. PORTA, C, and L appear to be the conveniently grouped pins on the Arduino Mega.
6  Community / Bar Sport / Re: Lead free solder on: September 11, 2014, 10:29:16 am
The last primary lead smelting operation in the US closed its doors at the end of 2013 (Doe Run, in Missouri) because, in part, the EPA was going to force them to store their ore in enclosed buildings. So, yeah, lead sheltering would have made it look like a freshly bathed puppy smiley-wink

Smelting lead ore isn't inherently dangerous; it's the airborne dust from handling the ore that's a problem. Lead melts around 600F and you have to get it around 1600F for vapor to become a problem.
7  Community / Bar Sport / Re: Lead free solder on: September 10, 2014, 10:16:02 pm
Lead is more abundant than tin and much easier to mine, but then I suppose the fact that tin is worth ~ten times what lead is worth is enough evidence of that. Pound for pound I would expect a lead mine to be much less destructive to the environment.

What's "lead sheltering"?
8  Using Arduino / Motors, Mechanics, and Power / Re: Mechanism, Linkage, Gear Design on: September 10, 2014, 01:00:29 am
You might find it interesting to poke around KMODDL
9  Products / Arduino Yún / Re: SSH over ssh on: September 09, 2014, 09:11:09 pm
You'd need to provide complete network details: the IP of the PC, Yun, and "box". "ifconfig -a" and "netstat -rn" output from the Yun would be helpful. And stop defining this mystery "box" by color and state what the device actually is.
10  Topics / Science and Measurement / Re: Making an Arduino multimeter on: September 09, 2014, 03:33:19 pm
Google "Ardutester".
11  Topics / Science and Measurement / Re: INA125P on load cell on: September 09, 2014, 03:30:51 pm
You need to adjust the gain for more swing. In your diagram, the 1K resistor equates to approximately a 60x gain. A 500 ohm resistor would give you 120x gain, a 250 ohm resistor 240x gain, ad nauseum.
12  Using Arduino / Project Guidance / Re: which IR Beam trip wire method with <3ms output response on: September 09, 2014, 12:38:08 pm
Search the forum for "TSSP4038". That's 1/38000ths of a second (.000026) accuracy.
13  Community / Exhibition / Gallery / Re: Using an Arduino for high speed photography on: September 08, 2014, 01:44:34 am
Spark air gap gives very little illumination though.

You might like to consider shock tube which can get bright light at a few millionths of a second exposure.

I've heard of an air gap flash but not a "shock tube". And unfortunately the googles - they do nothing.
14  Topics / Robotics / Re: Help in the components of the quad copter on: September 08, 2014, 01:25:44 am
ArduCopter is a fully featured controller, performing not only the balancing/stabilization of the quadcopter but also capable of being programmed with flight paths, programmed with takeoff/landing routines, and it can add telemetry. Look up "Ardupilot GCS" for details. Basically, with a controller like Arducopter, you can properly label your copter as a "UAV".

Cheaper controllers with "KK multicopter" or "MultiWii" firmware frequently don't even have a capability of adding GPS. They'll work fine for a copter that only needs manual control, but GPS functionality is extremely helpful when you just want the copter to hold position (like for photography).
15  Products / Arduino Yún / Re: SSH over ssh on: September 08, 2014, 01:12:57 am
Your Yun, by default, is configured to set IP addresses on its Wifi and ethernet interfaces using DHCP. Your Wifi router assuredly has a DHCP server on it so the IP gets set. Your "black box" (note: telling us the color of the box isn't helpful) either doesn't have a DHCP server or it's trying to serve addresses in the same range as the wireless router's DHCP server. If it's the former then you'll need to configure an IP on the ethernet port manually and then add a route so that the Yun knows to use the ethernet port to make connections to your black box., and if it's the latter then you'll just need to add the route.
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