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Re: Sparkfun Relay problem - something wrong?

 by riden ¦  Sat Feb 27, 2010 5:15 pm ¦  Forum: AVR Microcontrollers ¦  Topic: Sparkfun Relay problem - something wrong? ¦  Replies: 5 ¦  Views: 1180

Great! Perhaps the LED is inserted backwards. Have fun with your project.

Re: Sparkfun Relay problem - something wrong?

 by riden ¦  Sat Feb 27, 2010 4:16 pm ¦  Forum: AVR Microcontrollers ¦  Topic: Sparkfun Relay problem - something wrong? ¦  Replies: 5 ¦  Views: 1180

I looked at the schematic of the relay board and just about any general purpose NPN will work for you.

Re: Sparkfun Relay problem - something wrong?

 by riden ¦  Sat Feb 27, 2010 3:38 pm ¦  Forum: AVR Microcontrollers ¦  Topic: Sparkfun Relay problem - something wrong? ¦  Replies: 5 ¦  Views: 1180

The transistor that you have on hand is PNP and the circuit requires a NPN. They are completely opposite and need to be driven differently.

Re: Two Serial Ports

 by riden ¦  Fri Feb 26, 2010 7:19 pm ¦  Forum: AVR Microcontrollers ¦  Topic: Two Serial Ports ¦  Replies: 6 ¦  Views: 1374

Okay, I think I understand now. Can't you continue to use the (hardware, I presume) serial port for the capture and then use a software UART to transmit the data to the printer? You mention "sketches", so are you talking Arduino? If so, have a look at the software UART library.

Re: Two Serial Ports

 by riden ¦  Fri Feb 26, 2010 5:47 pm ¦  Forum: AVR Microcontrollers ¦  Topic: Two Serial Ports ¦  Replies: 6 ¦  Views: 1374

If you saying that you want two devices to talk with each other and one uses 7-E-1 and the other 8-N-1, that won't directly work. You would have to have software UARTS on both devices so one sends 7-E-1/receives 8-N-1 and the other sends 8-N-1 and receives 7-E-1. Tricky, but it could be done. If you...

Re: Do I need an amplifier?

 by riden ¦  Fri Feb 26, 2010 9:27 am ¦  Forum: SparkFun Product Questions ¦  Topic: Do I need an amplifier? ¦  Replies: 14 ¦  Views: 2524

Perhaps a stereo headphone chip that delivers 80-150 mw per channel driving 16 or 32 ohm speakers would work if you don't need huge amounts of volume. The chips are pretty cheap and can be powered from 1.8v on up depending upon the chip. National, STMElectronics, and Maxim are three manufacturers th...

Re: Forum server and software upgrade

 by riden ¦  Fri Feb 26, 2010 8:47 am ¦  Forum: SparkFun Site Questions/Comments ¦  Topic: Forum server and software upgrade ¦  Replies: 27 ¦  Views: 3671

Same here, both with IE 8 and Firefox 3. Otherwise, thanks for the upgrade!

 by riden ¦  Thu Feb 25, 2010 4:40 pm ¦  Forum: SparkFun Product Questions ¦  Topic: 3.5mm Audio Jack -- shorts the inputs when plug is inserted ¦  Replies: 29 ¦  Views: 4912

Yes, it slows the discharge of the capacitor until the protection kicks in. You might have to play around with the value. It might be easier to use a diode if your circuit can tolerate the forward voltage drop of the diode.

 by riden ¦  Thu Feb 25, 2010 4:01 pm ¦  Forum: SparkFun Product Questions ¦  Topic: my wine cooler ¦  Replies: 10 ¦  Views: 941

millis() is driven by an interrupt so delay() shouldn't be an issue. The simplest delay is a series of tight loops which the timer will periodically interrupt. Be sure to let us know if you get better timer results.

Edit: Egads, I just found an issue with the code I posted. I'll fix it.

 by riden ¦  Thu Feb 25, 2010 1:54 pm ¦  Forum: SparkFun Product Questions ¦  Topic: simple vibration/impact switch ¦  Replies: 3 ¦  Views: 1823

The following sensor works very well in these types of applications and would be preferable to a mercury switch (mercury is a toxic heavy metal). You could also roll your own sensor like lyndon suggested.

http://www.signalquest.com/sq-sen-200.htm

 by riden ¦  Thu Feb 25, 2010 12:00 pm ¦  Forum: SparkFun Product Questions ¦  Topic: 3.5mm Audio Jack -- shorts the inputs when plug is inserted ¦  Replies: 29 ¦  Views: 4912

I think that we can conclude that the problem is caused when both outputs of the device are momentarily connected to each other, the ring is momentarily connected to the shield (shorting one channel to ground), or a combination of both conditions. The MAX4410 has short circuit protection. My guess i...

 by riden ¦  Thu Feb 25, 2010 7:53 am ¦  Forum: SparkFun Product Questions ¦  Topic: 3.5mm Audio Jack -- shorts the inputs when plug is inserted ¦  Replies: 29 ¦  Views: 4912

The problem in my project is not audio quality, but rather that when inserting the headphones plug, the shorting of the left and right channel inputs causes a brown out condition. I have a few questions: 1) If you have the power off, plug in the headphones, and turn the power on, does it work as ex...

 by riden ¦  Thu Feb 25, 2010 7:15 am ¦  Forum: SparkFun Product Questions ¦  Topic: some weird effect of Telephone DTMF MT8870CE !!! ¦  Replies: 8 ¦  Views: 1145

vinodquilon wrote:Not INH pin, but PWDN pin of 8870 should be used for enabling 8870 after off-hook. INH only inhibits the detection of alphabet characters.
Thanks for the correction. I confess that I didn't consult the datasheet and assumed that it inhibited the detection. :oops:

 by riden ¦  Wed Feb 24, 2010 9:47 pm ¦  Forum: SparkFun Product Questions ¦  Topic: 3.5mm Audio Jack -- shorts the inputs when plug is inserted ¦  Replies: 29 ¦  Views: 4912

I checked continuity between pins 2 and 5. When no plug was inserted, the resistance was infinite (humor me). When I inserted the plug into the jack, there was a point when pin 2 was shorted to pin 5 -- the resistance dropped to 1 (one) ohm -- then went back to infinity after insertion was complete...

 by riden ¦  Wed Feb 24, 2010 8:45 pm ¦  Forum: SparkFun Product Questions ¦  Topic: 3.5mm Audio Jack -- shorts the inputs when plug is inserted ¦  Replies: 29 ¦  Views: 4912

After following this thread for a bit, I decided to take one of these connectors and make some measurements. Referencing the data sheet that the OP provided, I can confirm the following information: 1) Ground (sleeve) is pin 1 2) Tip is pin 5 3) Ring is pin 2 These are exactly as described in the da...

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