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Re: ok we have 3d printers now what

 by itikhonov ¦  Fri Jul 29, 2011 5:29 am ¦  Forum: SparkFun Product Questions ¦  Topic: ok we have 3d printers now what ¦  Replies: 6 ¦  Views: 855

Re: Arduino Powered Door Lock Item Question?

 by itikhonov ¦  Tue Jun 28, 2011 4:11 am ¦  Forum: SparkFun Product Questions ¦  Topic: Arduino Powered Door Lock Item Question? ¦  Replies: 2 ¦  Views: 531

This board provide only 1.2mA at 12V (because of 10k resistors).

So you need a mosfet http://www.sparkfun.com/products/10213 in addition to optoisolator. But this mosfet can only have 10V max at gate so you'll need something like a resistor to lower voltage before feeding it to gate.

Re: Mosfet with low Gate Source voltage?

 by itikhonov ¦  Fri Jun 17, 2011 2:25 am ¦  Forum: SparkFun Product Questions ¦  Topic: Mosfet with low Gate Source voltage? ¦  Replies: 5 ¦  Views: 2477

use digikey parametric search: http://search.digikey.com/scripts/DkSea ... at=1376381

Or use BJT.

Or may be p-channel mosfet will better suite your needs.

Or may be JFET.

Re: use a diode to ground ADC when not in use

 by itikhonov ¦  Tue Jun 14, 2011 2:10 am ¦  Forum: SparkFun Product Questions ¦  Topic: use a diode to ground ADC when not in use ¦  Replies: 7 ¦  Views: 1080

for the 22.2 v to the ADC i am using a voltage divider. I currently have this working with a 3s pack as i do not have a 6s to test with. One of the problems i am running into is i didn't realize was that resistors are not as close to there stated value as compared to what they actually provide. The...

Re: use a diode to ground ADC when not in use

 by itikhonov ¦  Mon Jun 13, 2011 9:26 am ¦  Forum: SparkFun Product Questions ¦  Topic: use a diode to ground ADC when not in use ¦  Replies: 7 ¦  Views: 1080

Use a resistor, 2 to 5k Ohm should work. I vote for something like 50k just in case. so would a diode be a better choice ? Or am i completely off on how a diode works. Well guys will correct me if i am wrong but that's how i see it: For atmega32u4 diode to ground circuit will look like this: | Vcc/...

Re: use a diode to ground ADC when not in use

 by itikhonov ¦  Mon Jun 13, 2011 7:12 am ¦  Forum: SparkFun Product Questions ¦  Topic: use a diode to ground ADC when not in use ¦  Replies: 7 ¦  Views: 1080

waltr wrote:Use a resistor, 2 to 5k Ohm should work.
I vote for something like 50k just in case.

Re: Small hobby generator

 by itikhonov ¦  Sun Jun 12, 2011 7:15 am ¦  Forum: SparkFun Product Questions ¦  Topic: Small hobby generator ¦  Replies: 8 ¦  Views: 4292

May be step down transformer with van de graaff generator?

Re: Simple audio gate circuit

 by itikhonov ¦  Fri Jun 10, 2011 8:07 am ¦  Forum: SparkFun Product Questions ¦  Topic: Simple audio gate circuit ¦  Replies: 4 ¦  Views: 1075

Ahh thanks, for some reason I thought that simply switching an analog signal with no kind of transformation could be done without a dedicated IC, but then again most things end up being a bit more complicated than I expected :> Well you can do that with single fet but i dunno about quality but look...

Re: Simple audio gate circuit

 by itikhonov ¦  Fri Jun 10, 2011 7:33 am ¦  Forum: SparkFun Product Questions ¦  Topic: Simple audio gate circuit ¦  Replies: 4 ¦  Views: 1075

There is a plenty from tons of manufacturers.

Here is onsemi for example: http://www.onsemi.com/PowerSolutions/pa ... .do?id=968

Here is maxim: http://www.maxim-ic.com/products/switches/audio/

Re: Control circuitry for a smoker

 by itikhonov ¦  Thu Jun 09, 2011 6:23 am ¦  Forum: SparkFun Product Questions ¦  Topic: Control circuitry for a smoker ¦  Replies: 7 ¦  Views: 954

apendleton wrote:
itikhonov wrote:smoker like "fog machine" or smoker like cooking?
The cooking kind.
DS18B20 is +125C max but looks like smoking is done at above 160C.

Re: Control circuitry for a smoker

 by itikhonov ¦  Thu Jun 09, 2011 12:04 am ¦  Forum: SparkFun Product Questions ¦  Topic: Control circuitry for a smoker ¦  Replies: 7 ¦  Views: 954

smoker like "fog machine" or smoker like cooking?

Re: Elevator floor level prediction using an accelerometer

 by itikhonov ¦  Wed Jun 08, 2011 10:19 am ¦  Forum: SparkFun Product Questions ¦  Topic: Elevator floor level prediction using an accelerometer ¦  Replies: 17 ¦  Views: 2656

NitroxDM wrote:Is there anything in the existing system you can tie into.
Probably one needs quite cool and expensive license to do anything with elevator or shaft.

Re: Elevator floor level prediction using an accelerometer

 by itikhonov ¦  Wed Jun 08, 2011 10:17 am ¦  Forum: SparkFun Product Questions ¦  Topic: Elevator floor level prediction using an accelerometer ¦  Replies: 17 ¦  Views: 2656

installed in the car. May be it's worth adding rfid on each floor so when doors open you can be sure which one they open at. You will still need to use your "guessing" method with accelerometer to display floors in-between because probably there is no reception in this metallic horror box. But you ...

Re: sweeping a Laser electronically

 by itikhonov ¦  Wed Jun 08, 2011 9:01 am ¦  Forum: SparkFun Product Questions ¦  Topic: sweeping a Laser electronically ¦  Replies: 14 ¦  Views: 1436

Also check this: http://spt06.chez-alice.fr/00/lasers.htm

don't miss links on the left there are two more pages on topic. although they all use some sort of mechanical components.

Re: usb host shield - 5v regulator getting very hot.

 by itikhonov ¦  Wed Jun 08, 2011 3:05 am ¦  Forum: SparkFun Product Questions ¦  Topic: usb host shield - 5v regulator getting very hot. ¦  Replies: 3 ¦  Views: 496

LM1117 regulator has internal current limiting and thermal protection but you are asking trouble anyway. If you don't scared of doing some math read LM1117 datasheet section 5.0 and calculate wherever you have problems or not. Or you can measure temperature of regulator and if it's beyond or near 12...

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