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16  Community / Bar Sport / Re: Has Atmel significantly raised 8-bit MCU prices recently or is this Digikey? on: April 14, 2014, 01:11:47 pm
USA price (used whichever cheaper, mouser or digikey, Newark was never the best deal.)
2/17/2012 Mouser 100 ATMEGA328P-PU for $290 $2.9/each
10/15/2012 Digikey 112 same chip for $202, $1.8/each
5/12/2013 Mouser 112 same chip for $202, $1.8/each
3/3/2014 Mouser 112 same chip for $304, $2.7/each

Yes, the price has gone up but I can't help it. Have to have many of those suckers for my kits and builds. I have less than 100 left. Will take a vacation so please keep me posted on the price. I really should have dumped $200 towards the end of last year on more chips. Now I wasted about $100 extra. You never run out of ideas where to put them on a new design or build existing ones.

Plus, please buy multiples of 14 (14/tube) so they don't have to cut a tube. smiley-wink
17  Using Arduino / Project Guidance / Re: Arduino for this? Or something else? on: April 14, 2014, 01:01:50 pm
Very nice of you to get a project going with your dad. Good for you!

As for hardware, neither arduino nor raspberry pi is required for a simple trigger. You can get this following module and hook the opto output to one of the trigger pins. You may want to add some small caps to smooth the rise of the signal so it doesn't trigger too many times. If you are unsatisfied with the result , get a small arduino clone on ebay, such as arduino nano, and program a debounce code and add a guard so when the sound is triggered, it will not be triggered again for a fixed time. Make sure it's long enough so subsequent cars don't all trigger the sound as they pass, unless that's your intention.

I don't have personal experience with this module but one of my clients vouches for it.
18  Using Arduino / Project Guidance / Re: how to drive robot straight... on: April 14, 2014, 12:29:44 pm
You have two identical wheels and do the same things to both, but the path isn't straight? Welcome to the real world!

The frictional condition on the ground varies between the wheels so they will never go straight even with encoders saying they've spun the same amounts. When you started your motors, did you apply full power right on, or did you ramp up power from low to high? Same goes with stopping. Also you should slow down overall speed to make sure you always have traction. If you can do the above, you will get straighter. To get it really straight, you need external feedback on the straightness of the path or smart grid in space to tell you where you are at and which way you head.

Ever seen GPS-controlled combines working fields? Me not, but I know they go very straight smiley-wink
Ever driven a car along a straight stretch of highway? Me, a lot, and I know I always need to keep my hands on the steering wheel and eyes on the road (follow straight lines).

Those were examples of external feedback (road lines) and smart grid (GPS). Many robots can follow lines drawn on the floor, FYI.
19  Using Arduino / Project Guidance / Re: Count 18 lines and pause. on: April 14, 2014, 12:22:53 pm
No, at the moment, your main problem is that you're not showing us all the code.

Plus, not following any tutorial I posted, about "for loop".

OP, if you don't follow that tutorial or find out more about for loop, you're wasting your time. Get FOR loop LEARNT!
20  Community / Website and Forum / IE token problem forum not loading on: April 14, 2014, 11:38:41 am
This is what I sometimes get browsing the forum on desktop version of win8 IE:

The token changes from time to time but no page will load. Strangely enough, the metro version IE works fine.
21  Development / Other Hardware Development / Re: Arduino shield pins and ICSP header mismatched height on: April 14, 2014, 11:32:05 am

Honestly, how many shields have pass-thru headers? I count mine, and which else (I think one of the adafruit or sparkfun shields).

According to arduino team's product stock photo, none of their shields have pass-thru headers:

Here is mine:

I might just bite the bullet and add SD card and xbee support stuff on this shield, going with surface mount ATMEGA328P-AU, and forget about stacking. At least for one project it will eliminate the official arduino wireless (xbee) shield.
22  Using Arduino / Project Guidance / Re: Count 18 lines and pause. on: April 14, 2014, 12:37:40 am
Can you provide an example of what you're trying to achieve?

I thought OP just wants to print 18 lines of random numbers and pause for input. I posted how to use for loop. Can't be easier than that, since 18 is a fixed magic number.
23  Development / Other Hardware Development / Arduino shield pins and ICSP header mismatched height on: April 14, 2014, 12:20:29 am
I have noticed that arduino official shields, such as wifi and wireless shields, have mismatched ISCP header height with male pins. Both point down, but the male pins are 2mm or 0.1" longer.

My first picture shows me holding a PCB over a MEGA, showing that the female headers and at the same height as the ICSP male header on arduino.

My second picture shows three shields, from left to right, official wifi shield, official wireless shield, and a third-party Ethernet shield. As you can see, both official shields have male pins about  2mm or maybe 0.1" longer than the female ICSP header so the female header is not touch the table top. On the other hand, the third-party shield have same height.

This may create loose connection issues when you press the shield against another shield with pass-thru ICSP headers, which are thin pins, not square pins found on arduino. The additional 0.1" travel on the female header makes the connection so much more trust-worthy. I have some issues with some shields I designed and built with wifi shields. I don't know if it was caused by this "feature". From what I understand, all pins should make perfect contact, not some doing it while others have ways to go.
What is your opinion?

To remedy this, I made a tool, by pulling all the pins in a row of female header, indicated in the third picture. Then I slip it over the male headers, and I just have to trip the protruding portion of the male header in half, effectively removing about 2mm length.
24  Development / Other Hardware Development / Re: List of tools for surface mount work on: April 14, 2014, 12:09:15 am
OK, I added your recommendations to my list. Unfortunately my weller solder pencil or station is needing repair. Its temperature sensor is on the verge of breaking. See picture of "NO temperature" and correct temperature. Very disappointed with $350 of investment. May get a hakko instead with the grant. This weller is for home business.

CR, so if I do get a rework station, and a proper nozzle, all I have to do is to add solder paste to the pads, place MCU, attach proper nozzle, and heat up, right? That sounds easier than soldering every pin or even drag soldering. I have a chiseled tip that I think should work for drag soldering. Just need flux.
25  Development / Other Hardware Development / Re: List of tools for surface mount work on: April 13, 2014, 11:49:19 pm
Really sorry I left the post a couple days. Been busy changing passwords all over, due to the heartbleed security issues. Still have too many more sites to go.
26  Development / Other Hardware Development / Re: Info post: Seeedstudio PCB pricing matrix on: April 13, 2014, 11:45:44 pm
And they are still shipping with desiccants. I don't know if that's good or not for transportation. Seeed says that's not allowed by their mail carriers. Anyway, it's good to know the boards are dry.
27  Using Arduino / Storage / Re: SD card create new file on: April 09, 2014, 11:27:31 am
I want create many files in SD card after some interval for the same code. now i can create only one file which function i have to add in this program.

You should ask the original poster to share updated code. As you can see, the original code DOES NOT work, which is why it was posted here for help.
28  Development / Other Hardware Development / List of tools for surface mount work on: April 09, 2014, 10:44:24 am
I am putting together a list for prototyping designs with surface mount parts, mainly for myself. But it will help anyone else with the same question.

I've never done surface mount before and only got one design on PCB with surface mount parts so far. I've not soldered parts on the board yet. I am trying to figure out what tools I need to do the job. I received some grant and the work is open source and for teaching. So I can afford some nicer tools. Here is my very short list of tools:

1. [EDIT] This German iron just crapped out on me. Got to get hold of repair service (seems only one person for whole USA). "Nice" solder iron with micro/mini tips. I got that. Weller WD1001 and a micro tip. The set already includes a small tip.
2. Fume extraction from OK electronics
3. Vacuum pickup pen for MCU
4. Tweezers ESD Adafruit and sparkfun both sell them. I might get the angled nose one and a pair of straight one
5. 0.022" diameter solder (lead-free) RadioShack has them for $8 3oz, or search the web to find cheaper ones. I just hang a few spools of different sizes with hook-loop straps on my fume extractor. Grab the end and solder away!
6. Some magnifiers (for me?!)
7. I found a couple of multimeters for surface components around $25 at sparkfun and adafruit. Would be nice to know what you're soldering before doing the job.
8. Maybe I will get a rework station instead of oven. I don't know how that will work out with the business office. When I was in school I bought a pair of noise cancelling head sets, so I can hear people talk while working in super noisy environment (we tend to yell and get in bad temper in that noisy lab). But school paper pusher decided this thing can play music, so no reimbursement.
9. Solder paste
10. Squeegee? What is that, precious? If I don't have stencil, say for prototyping, what tool is best for spreading?
11.  What else do you use specifically for surface mount?

FYI, I will only have may be up to 3 IC (including ATMEGA328P-AU) that are surface mount and one SD card slot, and 0603 chip resistors and caps.

So what do you think I am missing? I am interested in very small production runs say 20 units etc. I don't think I'll get reflow oven etc.

Thanks for your input!
29  Using Arduino / Project Guidance / Re: Count 18 lines and pause. on: April 09, 2014, 10:24:01 am
OK, set the button press requirement aside, and try just taking a character from the serial port for simplicity so you can understand how to get the counter to work.

The way you set it up, the variable counter is not doing anything. If you always print 18 lines of 6 numbers, you should use a for loop.

The above example code shows how to do something 256 times. You can use this as a template. Then at the end of your loop() function, before you close the "}", add while(1){} to stop the execution. You will see 18 lines and then stop. This is your step one, get 18 lines and stop.

Your next step is to replace the while(1){} with something that can make the code run again for 18 lines.
Replace it with

30  Using Arduino / Project Guidance / Re: ideas for using exterior light fixture to power Arduino, fishing for ideas. on: April 09, 2014, 12:18:56 am
Your idea seems pretty sound to me. I don't see why you can't just do it  smiley-surprise
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