Search found 380 matches

by macegr
Wed Jul 11, 2012 12:06 pm
Forum: SparkFun Product Questions
Topic: DS3234 is gaining about 2 seconds a day
Replies: 5
Views: 988

Re: DS3234 is gaining about 2 seconds a day

I don't think this will solve your problem, but you're actually enabling battery-backed square wave output. It's pretty unlikely that you really want to do that, as it will increase the power drain of the device when it's off.
by macegr
Thu Jun 28, 2012 5:23 pm
Forum: PCB Design Questions
Topic: Eagle "net overlaps pin"(or:"i am now homicidal...look out")
Replies: 4
Views: 2551

Re: Eagle "net overlaps pin"(or:"i am now homicidal...look o

I have been using Eagle for nearly 12 years and have never seen that particular error.
by macegr
Tue May 29, 2012 3:09 pm
Forum: New Product Ideas
Topic: FT-X breakout boards
Replies: 3
Views: 2245

Re: FT-X breakout boards

I can at least verify that the FT230X works beautifully for an Arduino bootloader on a 3.3V system, since avrdude now pulses both DTR and RTS for reset.
by macegr
Tue May 29, 2012 3:00 pm
Forum: PCB Design Questions
Topic: Custom step-up circuit?!
Replies: 6
Views: 1245

Re: Custom step-up circuit?!

Do you know for a fact that your 1400mAH battery can handle 7A+ output current without tripping the current limit?
by macegr
Mon May 21, 2012 11:56 pm
Forum: SparkFun Product Questions
Topic: CNC machine vacuum table won't hold single sided PCB. Ideas?
Replies: 29
Views: 4451

Re: CNC machine vacuum table won't hold single sided PCB. Id

You don't actually need holes going to the top side of the MDF at all. You can mill a grid of channels in one sheet of MDF, leaving support structures between the channels. Paint lightly with wood glue to seal it, then let dry. Next, take a sheet of 1/4" MDF and mill both sides just a tiny bit, enou...
by macegr
Wed May 02, 2012 1:23 am
Forum: SparkFun Product Questions
Topic: TX/RX Level Shifting with LED
Replies: 20
Views: 1700

Re: TX/RX Level Shifting with LED

In my experience, that circuit doesn't work well at all for any amount of load on either side of the converter. It's primarily useful for communications between CMOS chips.
by macegr
Thu Apr 05, 2012 8:55 pm
Forum: PCB Design Questions
Topic: Choosing the right Tantalum Cap?
Replies: 12
Views: 1951

Re: Choosing the right Tantalum Cap?

I refuse to use tantalums if at all possible. They're expensive and their typical failure mode is to burn up. I'd derate them massively for an unproven application. They're especially bad across things like high amperage power supplies or batteries...the high current spike can cause them to fail aft...
by macegr
Wed Apr 04, 2012 3:35 pm
Forum: PCB Design Questions
Topic: Short checklist compiled from these posts
Replies: 4
Views: 1070

Re: Short checklist compiled from these posts

I've never exactly understood why 90 degrees angles are a bad idea. Can anybody explain this a bit? It's mainly just acid traps, really, unless you're designing a circuit over 30GHz. Vias are an example of an extreme right angle and they don't affect radiated emissions at the operating frequencies ...
by macegr
Tue Apr 03, 2012 5:02 pm
Forum: PCB Design Questions
Topic: Eagle SMD pad soldermask size?
Replies: 16
Views: 14615

Re: Eagle SMD pad soldermask size?

It is normal for many fine-pitch devices to have no soldermask between the pins. The soldermask process is not usually as accurate as the PCB process, and if the paste is applied correctly the feature size relative to surface tension and volume of solder makes it less likely for a solder bridge to f...
by macegr
Sat Feb 04, 2012 12:18 am
Forum: SparkFun Product Questions
Topic: Integrating an USB car charger
Replies: 4
Views: 543

Re: Integrating an USB car charger

You can get tiny switching USB 5V regulators that plug into a cig socket already. Just splice on some wires, add some heatshrink, drill a hole where you want the plug, and glue it in place as is. Already shaped like a panel-mount socket. Examples: http://www.dealextreme.com/p/designer-s-car-cigarett...
by macegr
Fri Feb 03, 2012 3:07 pm
Forum: SparkFun Site Questions/Comments
Topic: Simple parts inventory program? (free or opensource)
Replies: 21
Views: 38881

Re: Simple parts inventory program? (free or opensource)

Excel spreadsheets are very commonly used for BOM management in industry. You can specify as many parameters about a part as you like, you can do on the fly calculations for cost estimates, you can put in the sizes and pad counts for manufacturing estimates, you can insert notes, you can assign hype...
by macegr
Tue Jan 31, 2012 12:20 am
Forum: Arduino
Topic: Spinning clock for theatre
Replies: 6
Views: 1531

Re: Spinning clock for theatre

If the audience is not going to see the clocks moving, then having someone physically walk up and move the hands would probably be the most fail-safe method. The stepper motor doesn't care if it gets yelled at for not doing its job ;)
by macegr
Sun Jan 22, 2012 11:34 am
Forum: PCB Design Questions
Topic: USB on PCB
Replies: 6
Views: 1110

Re: USB on PCB

Not going to download something from Mediafire. Your image was probably way too big, resize it. You can also use handy upload services like Imgur or Flickr and include the image right in your post. But try to keep it less than 600 pixels wide. Learning how to upload images to the internet will be a ...
by macegr
Fri Jan 20, 2012 10:38 pm
Forum: SparkFun Product Questions
Topic: What are wrong with my soldering skills?
Replies: 14
Views: 1708

Re: What are wrong with my soldering skills?

It has to be the solder. Throw it away and buy this stuff: http://www.sparkfun.com/products/10243 I've never used it (still whittling down my 5 pound stash of Multicore and Alpha Metals) but I will trust Sparkfun on it. With lead-free solder, make sure to get everything set up, get in, get out, don'...
by macegr
Mon Jan 16, 2012 3:07 pm
Forum: SparkFun Product Questions
Topic: Arduino or Rasberry Pi?
Replies: 11
Views: 1243

Re: Arduino or Rasberry Pi?

I think the PR around the Pi is a little damaging, honestly. The Arduino is a perfect introduction to basic concepts of integrating firmware and hardware. As simple as it is, a lot of people new to the field have plenty of difficulty grasping simple electronic concepts and learning C. The Raspberry ...