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 by riden ¦  Wed Feb 24, 2010 8:19 pm ¦  Forum: SparkFun Product Questions ¦  Topic: some weird effect of Telephone DTMF MT8870CE !!! ¦  Replies: 8 ¦  Views: 1143

I'm not sure exactly what you want to do, but I think you want to be able to call into this device and have it decode your DTMF tones sent by the caller. If that is the case, the device should only be activated when the phone is answered. This presumes that your device isn't doing the answering. If ...

 by riden ¦  Wed Feb 24, 2010 2:47 pm ¦  Forum: SparkFun Product Questions ¦  Topic: Do I need an amplifier? ¦  Replies: 14 ¦  Views: 2522

STMMicroelectronics use to make 1 to 2 watt single chip stereo amplifiers, but I don't know what is currently available.

 by riden ¦  Wed Feb 24, 2010 2:03 pm ¦  Forum: SparkFun Product Questions ¦  Topic: Do I need an amplifier? ¦  Replies: 14 ¦  Views: 2522

Yes you will need an amplifier. An LM386 based amplifier should provide a low cost solution for you.

Re: some weird effect of Telephone DTMF MT8870CE !!!

 by riden ¦  Wed Feb 24, 2010 1:36 pm ¦  Forum: SparkFun Product Questions ¦  Topic: some weird effect of Telephone DTMF MT8870CE !!! ¦  Replies: 8 ¦  Views: 1143

vinodquilon wrote:The problem is that, When I calling from remote end all the LED s blinking randomly for 1 sec (undesired result) and then
comes to a stable state.
Caller ID signaling?

 by riden ¦  Wed Feb 24, 2010 10:33 am ¦  Forum: SparkFun Product Questions ¦  Topic: SN754410E woes ¦  Replies: 11 ¦  Views: 2880

I'm a dunce. Sorry, should have gone to bed earlier. :oops:

According to the TI datasheets, both the SN754410 and L293D have the internal protection diodes. The L293 does not and would require external diodes for protecting the chip.

 by riden ¦  Wed Feb 24, 2010 7:27 am ¦  Forum: SparkFun Product Questions ¦  Topic: electronic component to switch between 2 signal sources ¦  Replies: 4 ¦  Views: 369

You could use a hex inverter like a 4069 to invert the logic levels or if you are driving the 4066 from a microcontroller, simply invert the logic in software.

 by riden ¦  Tue Feb 23, 2010 8:37 pm ¦  Forum: Wireless/RF ¦  Topic: Looking for Cheap Hack ¦  Replies: 4 ¦  Views: 674

I would be interested in other views, but I don't think you are going to be able to do this satisfactory for less than $20-25 per button on the low side. The big challenge is mitigating collisions caused by everyone buzzing in at the same time is such a way that the system is responsive. The low cos...

 by riden ¦  Tue Feb 23, 2010 7:39 pm ¦  Forum: Wireless/RF ¦  Topic: How do I...? real time data display over the internet ¦  Replies: 16 ¦  Views: 2264

You will only need one AJAX session originated by your remote client to your local server. Some way to quickly accumulate data from the sensors and so your local server can dish the data out when required will be needed. If you know a little something about programming, you could roll a simple webse...

 by riden ¦  Tue Feb 23, 2010 3:10 pm ¦  Forum: SparkFun Product Questions ¦  Topic: Efficient telephone audio (300-650Hz) fedback mechanism !!! ¦  Replies: 4 ¦  Views: 511

I forgot to say, I am feeding square pulses of audio frequency. I think all these problems can be solved by using RC or wein bridge oscillator at audio frequency. Thus replacing square pulses with sine waves. 10k will be replaced with 470 ohm at coupling path. What about my prediction ??? Won't mak...

 by riden ¦  Tue Feb 23, 2010 3:00 pm ¦  Forum: SparkFun Product Questions ¦  Topic: Driving 40kHz at 20V from 5V supply ¦  Replies: 40 ¦  Views: 8711

You might be on to something, at least I hope so. Kudos for sticking with this project, even though I'm sure it is frustrating at times. I know that sharing your tales helps others as well.

 by riden ¦  Tue Feb 23, 2010 2:43 pm ¦  Forum: SparkFun Product Questions ¦  Topic: SN754410E woes ¦  Replies: 11 ¦  Views: 2880

Sorry about not answering your question about the braking, but the 754410 does have the internal diodes. The L293D's do not. So you're not completely confused. :)

 by riden ¦  Tue Feb 23, 2010 9:00 am ¦  Forum: SparkFun Product Questions ¦  Topic: is there any way to insulate bare wire after the fact? ¦  Replies: 16 ¦  Views: 3494

i have tried the sand papper and i think i wana just keel over its to time consuming to do each wire like that.... i would have to doit like 5k+ times Yes, I can see how sanding 5k ends would be a pain. :( I don't think applying some type of insulation is going to be easier than a sanding technique...

 by riden ¦  Mon Feb 22, 2010 6:57 pm ¦  Forum: New Product Ideas ¦  Topic: how to find out more about smart antenna ¦  Replies: 3 ¦  Views: 637

Try Googling "rca digital converter smart antenna". Apparently these are antennas that can be used in high signal strength areas to address multipath issues. In the analog days, multipath expressed itself as ghosting. These antennas can be electronically rotated and have adjustable gain settings.

 by riden ¦  Mon Feb 22, 2010 12:48 pm ¦  Forum: SparkFun Product Questions ¦  Topic: is there any way to insulate bare wire after the fact? ¦  Replies: 16 ¦  Views: 3494

...the main reason was its small and will be hardly noticible at a distance unlike using a plastic insolation. I would think dipping uncoated wire into an insulator will be much more noticeable than the lacquer coating on the magnet wire. As esklar81 said, sandpaper is a good choice. I use a fine g...

 by riden ¦  Mon Feb 22, 2010 7:57 am ¦  Forum: SparkFun Product Questions ¦  Topic: my wine cooler ¦  Replies: 10 ¦  Views: 939

The following should provide better accuracy. I haven't confirmed that the following code is correct Wiring syntax, but you can get the idea. Your clock will drift over time, but maybe this will be good enough for your purposes. The strategy is to set a target one second in the future. In the main l...

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