Search found 356 matches

by Blackfin
Sun Jun 23, 2013 3:36 pm
Forum: PCB Design Questions
Topic: Protel PCB layout package?
Replies: 10
Views: 5463

Re: Protel PCB layout package?

OP: It sounds like your "senior" design engineer is an old graybeard who walks around grumbling and mumbling to himself about " ...in the old days we used to lay out boards with tape and markers... " How can anyone with any CAD experience in schematic capture and PCB layout -- assuming the old fart ...
by Blackfin
Thu Jun 13, 2013 10:30 am
Forum: SparkFun Product Questions
Topic: Use serial lcd to view coordinates of a potentiometer
Replies: 9
Views: 1129

Re: Use serial lcd to view coordinates of a potentiometer

What are you actually seeing on the LCD?
by Blackfin
Sat May 25, 2013 5:51 pm
Forum: SparkFun Product Questions
Topic: Transistor Turn Signal Circuit (Incandescent)
Replies: 20
Views: 2815

Re: Transistor Turn Signal Circuit (Incandescent)

FWIW, the technique of driving the 3055 with a second transistor is fine but it's a discrete implementation of a Darlington transistor, which puts both transistors in one package. IOW, you'll need a series resistor, a couple of pull-down resistors and two transistors to do discretely what you could ...
by Blackfin
Sat May 25, 2013 2:30 pm
Forum: SparkFun Product Questions
Topic: Transistor Turn Signal Circuit (Incandescent)
Replies: 20
Views: 2815

Re: Transistor Turn Signal Circuit (Incandescent)

Yes, a schematic would definitely be helpful. The datasheet for the TIP3055 shows that it has a minimum hfe of 20 at 4A collector current. At 10A it's just 5. This means that you'd need a base current of 4/20 or 200mA to properly conduct 4A and you'd need 10/5 or 2A of base current for 10A of collec...
by Blackfin
Sun May 19, 2013 6:45 am
Forum: SparkFun Product Questions
Topic: Looking for an Arduino but not an Arduino
Replies: 4
Views: 739

Re: Looking for an Arduino but not an Arduino

Why not just use the processor that was on the Arduino board? An Atmel Atmega328...
by Blackfin
Fri May 17, 2013 5:30 pm
Forum: SparkFun Product Questions
Topic: Problem getting LCD-09053 3.3V display working
Replies: 9
Views: 1103

Re: Problem getting LCD-09053 3.3V display working

I definitely don't think Vo should be grounded. Put a pot on it.

Hook up the analyzer or scope again and verify all of your signals and timing.
by Blackfin
Thu May 16, 2013 5:38 pm
Forum: SparkFun Product Questions
Topic: Problem getting LCD-09053 3.3V display working
Replies: 9
Views: 1103

Re: Problem getting LCD-09053 3.3V display working

Good question. Check some of the comments on the product page at Sparkfun. It appears you're not the only one to see some issues running at 3.3V.

Are you sure you have the contrast setting correct?
by Blackfin
Wed May 15, 2013 10:42 am
Forum: SparkFun Product Questions
Topic: Problem getting LCD-09053 3.3V display working
Replies: 9
Views: 1103

Re: Problem getting LCD-09053 3.3V display working

Assuming you've got the control signals and databus correctly connected you might re-visit the datasheet for the LCD controller. For example, in the datasheet linked to on the product page: http://www.sparkfun.com/datasheets/LCD/st7066.pdf the 4-bit initialization sequence contains three writes to t...
by Blackfin
Tue May 07, 2013 4:06 am
Forum: SparkFun Product Questions
Topic: on/off 220v Fan driven by arduino
Replies: 5
Views: 1982

Re: on/off 220v Fan driven by arduino

The first relay could be made to work, in theory, if you used a 2N3904 (e.g.) transistor to switch the coil current and had a 12V source to work with on the control board. Whether or not the relay itself is up to the task of conducting sufficient current for your fan/blower depends on the load prese...
by Blackfin
Mon Apr 08, 2013 9:54 am
Forum: SparkFun Product Questions
Topic: LM358 Op Amp Gain
Replies: 3
Views: 1420

Re: LM358 Op Amp Gain

A few thoughts: a) You might try a different op-amp, one that has a rail-to-rail rating. b) Add some bypass caps to pin 8, close to the device. b) You might also try changing the connections at pins 5 and 6 so that one is tied to 5V. With both tied to ground the op-amp may be oscillating like crazy....
by Blackfin
Thu Apr 04, 2013 4:50 pm
Forum: PCB Design Questions
Topic: Insulate and protect PCB
Replies: 4
Views: 1261

Re: Insulate and protect PCB

Generally speaking, a two-part, 5-minute epoxy works pretty well for holding down "fly wires." Put a blob where it connects to the board and a blob every inch or so along its length. Use a bit of tape to hold the wire down until the epoxy sets. A conformal coat is a good idea. Make sure you clean th...
by Blackfin
Sat Feb 23, 2013 4:45 pm
Forum: SparkFun Product Questions
Topic: Attaching SMT to a prototype board is driving me Crazy...
Replies: 5
Views: 1326

Re: Attaching SMT to a prototype board is driving me Crazy..

A good soldering station with a proper SMT tip: http://www.blackandco.com/govtsales/prod_images/ok_international_metcal_SP200.jpg plus some fine wire solder (making sure yout iron's tip/temperature, the board finish and the component legs are compatible with your choice of solder (e.g. lead-free or ...
by Blackfin
Sat Dec 29, 2012 11:03 am
Forum: SparkFun Product Questions
Topic: Inter-processor communication for robotic arm
Replies: 9
Views: 761

Re: Inter-processor communication for robotic arm

You might also consider I2C in your list of candidates.
by Blackfin
Wed Dec 19, 2012 5:14 am
Forum: SparkFun Product Questions
Topic: I2C Address question
Replies: 1
Views: 316

Re: I2C Address question

I don't think so since the I2C protocol uses ACKs from the slaves back to the master. Wouldn't be prudent to have them all doing it at the same time.
by Blackfin
Fri Nov 09, 2012 10:37 am
Forum: SparkFun Product Questions
Topic: Selling DIY electronics and legalities or regulations
Replies: 1
Views: 902

Re: Selling DIY electronics and legalities or regulations

If you talk to any test authority (UL, CSA, TUV etc) they will likely tell you that any "system" whose end-use configuration is mains-connected should be tested against the relevant standards like UL60950-1. If you use a power supply that carries a UL Listed mark and also includes an LPS (limited po...