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106  Forum 2005-2010 (read only) / Interfacing / Re: Power Supply and limit resistor for Infrared LED on: June 04, 2010, 08:44:56 am
The batteries are regular, non-rechargeable batteries. They are fairly fresh. I don't have a battery checker, but if the power dropped, the arduino would probably reset.

Is going over 5 volts ok?

If 5.5 volts is ok, this doesn't like a battery problem.

The TSAL 7600 can take 200 mA peak. I'm using NEC format. That uses a 38 MHz carrier. When the signal is high, the wave would be high 1/2 the time. So overall when transmitting it is on around 1/4 the time.

The current through the LED would be: 5.5 volts/50 ohms = 110 mA

That sounds good too. I tried a 25 ohm resistor, but that just made it much worse. (20% success at 10' instead of 80% success at 10', head-on.)

So I don't understand why dropping the resistor caused performance to deteriorate. And it doesn't sound like there is a problem with the amount of power. But maybe the constant current supply is worth doing? Do people get good results without doing this?

Infrared is kind of frustrating. It is hard to tell what is going on.
107  Forum 2005-2010 (read only) / Interfacing / Re: Power Supply and limit resistor for Infrared LED on: June 04, 2010, 06:50:17 am
Instructables has a circuit http://www.instructables.com/id/Power-LED-s---simplest-light-with-constant-current/, but this seems to be for a much more powerful LED, like something you would wear.

This only needs 200 mA peak.

How much power can 4 AA's make? Has any one played around with different power circuits?
108  Forum 2005-2010 (read only) / Interfacing / Power Supply and limit resistor for Infrared LED on: June 03, 2010, 09:22:31 pm
What is a good power supply for an Infrared LED, TSAL 7600?
http://www.vishay.com/docs/81015/tsal7600.pdf

I'm using 4 AA batteries that are about 5.5 volts. The LED is in series through a 47 Ohm resistor. It is powered through a transistor to overcome the Arduino's current limit.

How do you tell from the spec sheet what the maximum voltage and limit resistor to use?
109  Forum 2005-2010 (read only) / Interfacing / Re: Simple Motor Circuit on: March 31, 2009, 09:58:05 pm
Ok, i'll try it without the resistor. The arduino digital output switches a mosfet transisitor, so there is no danger of burning that out.

If the Arduino is powered by USB, how much current can I draw from Vin? Can I use that or any other pin to power motor?

Can SN754410 H-Bridge be powered in same way? Can this harm Arduino?

I was thinking of building shield with this chip as it sounds pretty simple (as opposed to buying a shield. Does that seem reasonable?
110  Forum 2005-2010 (read only) / Interfacing / Simple Motor Circuit on: March 29, 2009, 09:33:01 pm
I'm looking for a simple way to power a solarbotics GM3 gear motor - http://www.solarbotics.com/products/gm3/specs/

I'm trying to power it with the Arduino's Vin and ground through a 100 Ohm resistor. When turned on (its controlled by a transistor), the motor does not spin unless I give it a start.

Using USB to the Arduino, Vin should be 5 V. At 5V, the GM3 should draw 67 mA.

Should the Arduino be able to provide enough power? Should a smaller resistor or different pin be used?

Does anyone know a simple way to do this?
111  Forum 2005-2010 (read only) / Workshops / Re: Arduino Hacklab NYC on: June 11, 2010, 10:03:34 pm
LadyAda is not brick and mortar, but she is in NYC. So you should get your stuff fast.
112  Forum 2005-2010 (read only) / Exhibition / Re: home automation with arduino and android on: December 22, 2010, 12:47:48 pm
This post started out with the premise that other home automation systems are too expensive. Aren't X10 systems pretty cheap ($99 for controller and software)?

One issue with X10 is that they require a computer with X10 controller on 24/7. The computer provides a web interface and can turn devices on/off at scheduled times. For example, you may want to switch an outside light on automatically at 7 PM every day.

Have you given any thought to a server solution, i.e. leaving an android device at home and on 24/7 that can be connected to remotely?
113  Forum 2005-2010 (read only) / Exhibition / Re: Automatic Toilet Flusher on: October 18, 2010, 08:53:39 am
I know my wife will like it. She is quite tired of the children forgetting to flush. They are very lazy.

But seriously, has anyone ever had trouble with an overflowing toilet? The float shut-off value in the tank failed and the water overflowed from the top of the tank. It was clean water, but the flood caused over $10k in damage. I was thinking about building some kind of moisture alarm.
114  Forum 2005-2010 (read only) / Exhibition / Re: Arduino Powered Robot on: July 01, 2010, 09:24:03 pm
This is very nice. I'm building something similar with Tamiya tracks, Tamiya motors and a cardboard frame. It's a lot flimsier than yours, but also a lot cheaper.
115  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Connectors on: September 23, 2010, 09:36:44 am
I worry about the opposite, that my project will halt my marriage.

But too bad about the divorce.  smiley-sad
116  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Connectors on: September 23, 2010, 09:34:12 am
Molex's "How to recognize a good crimp": http://www.molex.com/tnotes/crimp.html

This is the kind of detail my obsessive mind needs!
117  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Connectors on: September 22, 2010, 11:36:53 am
Quote
Yes but sometimes the short end can be a little too short for a good connection. But then you can solder two headers back to back and have long pins on both sides.

That was the trouble I had with the Ping!, the short end was too short. No one sells longer connectors?

Quote
You have to get the crimp-on parts as well, little metal things that crimp onto your wire and push into the receptical. Normally the "official" crimping tools cost a fortune (and I mean a fortune, $400-700) but you can use narrow-nosed pliers.

Is it fairly easy to do with needle nose pliers (just insert the wire, squeeze and insert it in the receptacle)?
118  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Connectors on: September 21, 2010, 10:45:15 pm
Are Molex connectors a good way to connect 3 wires to a bread board? I think the Ping! ultrasound sensor has a molex connector, but I wasn't sure how to connect it to a bread board. Anyone know?
 
Can a connector like this be used with a bread board:


Does the short end go in the bread board and the long end go to a molex receptacle like:


How is bare wire connected to the molex receptacle? Is a tool required?
119  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Wheel and Frame Ideas on: April 23, 2009, 03:40:44 pm
The design is completely original but the inspiration is completely derivative. It is similar to many first bot projects.
120  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Wheel and Frame Ideas on: April 23, 2009, 03:31:35 pm
The wheel and frame are from a $250 Lego Mindstorm NXT. I wanted to give away a few as kits, so I didn't want to break up my NXT and I wanted it to be cheap.
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