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 by riden ¦  Sun Feb 21, 2010 10:57 pm ¦  Forum: Wireless/RF ¦  Topic: How do I...? real time data display over the internet ¦  Replies: 16 ¦  Views: 2255

Do a Google on AJAX. You can set up a web page that will only update the data the changes on the page (i.e., your control) instead of completely refreshing the page.

 by riden ¦  Sun Feb 21, 2010 9:52 pm ¦  Forum: SparkFun Product Questions ¦  Topic: my wine cooler ¦  Replies: 10 ¦  Views: 929

An external clock would make things a lot simpler and be more accurate in the long run. However, the millis() function should be interrupt driven and you could that value as the indicator for when to flip the seconds. Your current code always increments by one second. Using the millis() would take i...

 by riden ¦  Sun Feb 21, 2010 7:41 pm ¦  Forum: SparkFun Product Questions ¦  Topic: my wine cooler ¦  Replies: 10 ¦  Views: 929

One problem is that every time cool() is called, you are doing a 2 second delay creating at least a one second slippage. You will get better resolution if you adjust the seconds based on the actual number of milliseconds elapsed.

 by riden ¦  Sun Feb 21, 2010 2:05 pm ¦  Forum: SparkFun Product Questions ¦  Topic: 555 mono (restriction on Resistance value) ¦  Replies: 3 ¦  Views: 551

Okay, so it out with the 555 and in with the PICAXE. Regarding Eagle libraries, have you checked the Revolution (creators of the PICAXE) site? A Google of Eagle PICAXE libraries will get you here:

 by riden ¦  Sun Feb 21, 2010 1:56 pm ¦  Forum: SparkFun Product Questions ¦  Topic: Driving 40kHz at 20V from 5V supply ¦  Replies: 40 ¦  Views: 8588

Here are some thoughts that you may help your debugging. Relative to the CPU clock speed (8MHz?), 45 KHz is fairly low frequency. So I would examine these areas: 1) Your main programming loop is doing something that tickles a register when it doesn't have to (i.e., reinitializing some registers that...

 by riden ¦  Sat Feb 20, 2010 9:24 pm ¦  Forum: Wireless/RF ¦  Topic: looking for simplest wireless tech ¦  Replies: 12 ¦  Views: 1278

From your first post, it seemed you needed a single point-to-point communication. However, it is possible for multiple XBee devices to talk to the same endpoint, but I haven't had occasion to do that in a real application. Others on this forum, stevech in particular, can give you more enlightened in...

 by riden ¦  Sat Feb 20, 2010 8:29 pm ¦  Forum: Wireless/RF ¦  Topic: looking for simplest wireless tech ¦  Replies: 12 ¦  Views: 1278

The XBee has multiple inputs which can be either digital or analog and the XBee transmits its id, so I'd think it is a strong candidate unless cost is a major factor for your project.

 by riden ¦  Sat Feb 20, 2010 5:28 pm ¦  Forum: Wireless/RF ¦  Topic: looking for simplest wireless tech ¦  Replies: 12 ¦  Views: 1278

nomore wrote:How about sensor->xbee->air->xbee->usb zigbee regulator?
Yes, that's a good choice. I had forgotten about that XBee USB board. ... ts_id=8687

 by riden ¦  Sat Feb 20, 2010 3:25 pm ¦  Forum: SparkFun Product Questions ¦  Topic: Closing a circuit with a MOSFET ¦  Replies: 6 ¦  Views: 711

An analog switch is a device that acts like a relay in that you can provide a logic input and the outputs will "close" with a low resistance, typically a few ohms. Have a look at the datasheet for the 4066 (quad analog switch). It may fit your requirements.

 by riden ¦  Sat Feb 20, 2010 3:09 pm ¦  Forum: SparkFun Product Questions ¦  Topic: Closing a circuit with a MOSFET ¦  Replies: 6 ¦  Views: 711

What are the voltage and current requirements? Would a simple analog switch work?

 by riden ¦  Sat Feb 20, 2010 3:03 pm ¦  Forum: Wireless/RF ¦  Topic: looking for simplest wireless tech ¦  Replies: 12 ¦  Views: 1278

If you are going the XBee route, why don't you use the built in I/O mirroring? Buffer and level shift the inputs and outputs and you're good to go. Edit: Sorry. I didn't catch the part about USB. For that, you can use either a PIC or AVR chip as both have USB support. For example: http://www.obdev.a...

 by riden ¦  Sat Feb 20, 2010 11:59 am ¦  Forum: Wireless/RF ¦  Topic: looking for simplest wireless tech ¦  Replies: 12 ¦  Views: 1278

It is a bit misleading saying that just turning on the transmitter will result in a logic change on the other end. These receivers have an automatic gain control and you will see random noise on the output in the absence of a transmitted signal. You could also see interference from nearby devices (w...

 by riden ¦  Sat Feb 20, 2010 11:50 am ¦  Forum: SparkFun Product Questions ¦  Topic: 555 mono (restriction on Resistance value) ¦  Replies: 3 ¦  Views: 551

Yes, a 560k resistor will work just fine. You should see about a 61 second delay, depending upon the leakage of the capacitor. Because of the long delay time, I usually combine a fixed value resistor along with a variable resistor in series. For example, in your case, maybe a 390k fixed and a 250k p...

 by riden ¦  Fri Feb 19, 2010 3:49 pm ¦  Forum: SparkFun Product Questions ¦  Topic: 3.5mm Audio Jack -- shorts the inputs when plug is inserted ¦  Replies: 29 ¦  Views: 4768

I have used these connectors from Sparkfun and they don't short when the plug is inserted. Check your wiring or try another plug.

 by riden ¦  Fri Feb 19, 2010 3:48 pm ¦  Forum: SparkFun Product Questions ¦  Topic: Regulated 5v power supply from 3-8 volts ¦  Replies: 9 ¦  Views: 1120

Where do you see the datasheet say 7v max? Page 3 of the datasheet says a maximum of 26v. Naturally, you will want to keep the input voltage well below that for long life.

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