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1  Community / Bar Sport / Re: ship in a bottle 3D printer on: Today at 04:17:24 am
I have spent many hours drawing this high tech engineering drawing on a napkin :-)   ( I don't think you can see the wine stains on the scan .)

So how many bottles of wine did you drink, exactly?

I think it would be quite a challenge engineering it with such a long nozzle; the plastic needs to be hottest / least viscous at the very end of the nozzle or it'll jam. Also, to get the ship to stay in place while you're printing it you'd need to stick it to the bottle (use a "raft") and that would uglify it considerably.

With a big enough bottle opening, and a flat bottom, yeah I think it could be done though.
2  Community / Exhibition / Gallery / Re: My first Arduino on a PCB on: Today at 04:07:43 am
You can connect Aref to 5V, but if you do then you can no longer use an analogReference() that is anything other than EXTERNAL. For example if you had 5V connected to Aref and set analogReference(INTERNAL) then you would be shorting the internal 1.1V to that 5V. Magic smoke, etc.
3  Using Arduino / Sensors / Re: What's my best option for a sensor in this situation? on: Today at 03:55:14 am
What about something like this? Infrared emitter and detector in one package. This is just one example, I'm sure there are dozens of similar devices. It may be necessary to put some reflective tape or something on the bottom of the train if that is permissible. Or maybe it would work without it. At any rate, some experimentation would be needed.

You can blink the IR emitter and watch the change in value from the IR detector. If your detector is seeing ambient light then there will be a marginal change in reading between when the IR emitter is on or off, and if there is something reflecting the IR light then the change in reading will be much more pronounced.
4  Using Arduino / Sensors / Re: Weak Sensor Signals across Long Distance Wire on: Today at 03:49:44 am
I think you basically have a floating input and you're seeing random voltages. Longer wires would just increase that problem -- like a longer antenna. Add a high value resistor (~1 megaohm) between A0 and GND.
5  Using Arduino / Microcontrollers / Re: Change Vendor ID and Product ID in Firmware on: April 17, 2014, 11:53:03 pm
My bad, I thought the Mega 2560 used the FTDI chip but looks like only the older Mega 1280 does.
6  Using Arduino / Motors, Mechanics, and Power / Re: Can't decide servo or stepper on: April 16, 2014, 09:26:08 am
If the windmill is small enough that you can find a servo strong enough to hold it in position then the servo will certainly be easier to use. For a larger windmill you would probably want to use a geared DC motor but you would need to include some type of position feedback as well -- like a wheel encoder or magnetometer.
7  Using Arduino / Motors, Mechanics, and Power / Re: Simple connection brushless motor (fan) on: April 16, 2014, 09:21:46 am
First off, computer / brushless fans cannot be reversed. Bummer.

The fan itself contains its own three-phase driver circuit to control its direction and speed and won't work properly if you try to turn it off and on rapidly with PWM. It would be like trying to dim an LED connected to an Arduino by turning on/off the power to the Arduino.

If you're just controlling the speed you need some way to smooth out the power to the fan using something like an RC circuit or by increasing the PWM frequency. I'm sure there are a number of examples to be found if you look around.
8  Using Arduino / Microcontrollers / Re: Change Vendor ID and Product ID in Firmware on: April 16, 2014, 08:57:55 am
If you're using an Arduino Mega I don't understand why you would be using a FT232R USB UART board.
9  Using Arduino / Microcontrollers / Re: Change Vendor ID and Product ID in Firmware on: April 16, 2014, 12:10:38 am
If you have a board with the FTDI FT232RL (Official Mega) then you can use the FT_PROG utility. Pretty straightforward to use.
10  Using Arduino / Sensors / Re: Problem with using load sensor on: April 14, 2014, 03:28:42 pm
Until you get the gain adjusted properly you're going to see one of two results from the InAmp; either ~2V or ~4V.

If it's sitting at the ~2V value then your gain is too low. If it's at the ~4V value then the gain is too high. Keep playing with the gain until you get something in between, then decrease it a few ohms until it shows ~2V... and then you're ready to test it by pushing on the load cell.
11  Using Arduino / Project Guidance / Re: Automatic Pilot System for Sailboat Using Arduino on: April 14, 2014, 03:10:55 pm
Plan is to sub out the compass and go with a Fluxgate or similar.

If the "heading" output from a GPS won't work for you (the boat needs to be moving to get a heading output) then you want a magnetometer, a HMC5883 or similar. Sometimes you can find GPS + magnetometer combination modules as well.
12  Topics / Robotics / Re: Camera Stabilizer with MPU6050 IMU on: April 14, 2014, 03:45:38 am
The MultiWii code implements a gimbal option. You would be able to implement it as is or just use it as an example.
13  Using Arduino / Motors, Mechanics, and Power / Re: Driving 70v 6.3A Bipolar Stepper on: April 13, 2014, 04:23:45 pm
I don't see how to use it with my motor driver.   I need only a direction and step pin.

Specify it like:

AccelStepper myStepper(AccelStepper::DRIVER, stepPin, dirPin);
14  Using Arduino / Motors, Mechanics, and Power / Re: Deciding which servo fits better on: April 13, 2014, 04:08:55 pm
Here's a 360 degree servo. Metal output gear too.
15  Using Arduino / Motors, Mechanics, and Power / Re: DIspense very accurate micro volumes on: April 13, 2014, 04:06:28 pm
Ho, it looks very nice.

So there is the stepper AND the pump in this stuff right ?

It looks like the tubing was designed to sit on the top of the "pump" with a cover (missing) to hold it down tight; the white pieces apparently move up/down in a wave fashion to squeeze the liquid through the tubing. Never seen one like that before.

So if you can make a cover for it it'd probably work. Hard to go wrong at that price.
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