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1  Community / Bar Sport / Re: ARM Cortex-M7 on: Today at 03:34:53 pm
If I want more from an AVR, I think that the 1284P or the AT90USB1286 (because full speed USB) would be choice.
None of that is up to the full scale of what you outline.

But AVR's are like a white led in daylight compared to a Due or like.
I'm not comparing a Cortex to a PC. I get a rise comparing them to AVR's.
If I want to compare to a PC, I'd at least look at a Galileo.

Still I'm helping someone with software that uses a GSM shield... is there a phone in that? Any more phones can be PC's so I guess that'd be cheating. It does net. Does and ethernet shield get you there?

To keep perspective I think of the task and remember when PC's weren't up to what AVR's aren't up to.
That helps me know that my toys aren't just toys and that lets me appreciate them enough to feel a bit of awe.
2  Community / Gigs and Collaborations / Re: Inserting Start bit and Stop Bit in a serial communicatiom on: Today at 09:52:02 am
I was curious. X-10 is not real cheap.
3  Community / Bar Sport / Re: ARM Cortex-M7 on: September 30, 2014, 06:30:49 pm
I've always been puzzled why there is so little RAM on micro-controllers, I suppose there is a technical reason rather than just marketing.

I think it's mostly the range of niches that AVR's tend to fill, which is pretty wide.

Arduino is meant to be simple to get into. I haven't read the book but from what I've seen the idea is to fulfill the Wiring side of "Processing and Wiring".  Or at least that seems to have been the idea in 2008.

4  Community / Bar Sport / Re: ARM Cortex-M7 on: September 30, 2014, 06:24:40 pm

I see. And for those kind of things you seem to be right.
But people do use and sell internet shields and even run tiny servers on them.

Instead of packing loads of RAM in the MCU perhaps the answer is to run out a memory bus?

Rugged Circuits sells plug-in direct address external RAM  boards for the Mega2560. I have one, it was $25.

For what you describe, aren't those things serial in nature, driven by ports?
You see, the controller has a certain amount of RAM but unlimited data can be streamed, bandwidth is the limit.
I wonder how far SPI RAM would go in certain apps? Or how big SPI RAM chips get and if they can chain?
Is 48MHz fast enough to keep up? That's a Teensy 3.1 on slow speed.

5  Community / Gigs and Collaborations / Re: Inserting Start bit and Stop Bit in a serial communicatiom on: September 30, 2014, 01:09:47 pm
OP acts like a boss or client.

"What is wrong with you people?".

Maybe we've been fired or didn't pass the audition.
6  Using Arduino / Project Guidance / Re: Measuring the weight of a beehive on: September 30, 2014, 12:42:10 am
Microswitches do tend to wear out
a magnet and a reed switch would do the job nicely.

A reed switch will trip over a range of distance, much less tunable than capacitance or piezo touch.
Capacitance is still not as good as physical touch or light interrupt can be.
Piezo can tell how hard is the touch.

I am a fan of piezo disks after experimenting with them. There are cheap ones that work just fine as buttons.
They don't need debounce, give pressure data and can take a good bang. I got 100 for just over $10.
Downside is they need other components to work as I did. I used diodes, transistors and resistors.
7  Using Arduino / Project Guidance / Re: Measuring the weight of a beehive on: September 29, 2014, 10:52:58 pm
Microswitches do tend to wear out, I have a collection of dead computer mice to attest the fact.

You might take a look at light interrupt though a led as light source has a finite life even only lit during measure.
You might take a look at piezo disks as touch sensors, the sensitivity can be varied and the life is very long.
You might look into some form of capacitance sensor also with a very long lifetime and can be made really cheap.

I had mentioned putting the hive on a counter balance just to reduce the load cell required, months ago.
It's nice to see some physics used to engineer the parts needs down but running a motor will up power requirements.
8  Using Arduino / Project Guidance / Re: Simple water level indicator with input and output project on: September 27, 2014, 06:13:20 am
Big +1 on using the internal pullups!

Roy, the chip on an UNO has built-in resistors for each pin you can use so you don't have to wire your own.

You can read a pin with the pullup enabled and if it's not grounded it will be HIGH. If it's grounded it will be LOW. The pullup supplies the pin itself 5V at very low, easily drained, chip safe current. You can make a switch just by plugging a wire into a pin hole and grounding it. I've done it. I ground jumpers on that silver box the USB plugs into just because it's easier than pushing the end into a GND pin hole. Hey, I'm old and I need a magnifier to even find the damn hole!

There's down sides to hanging wires with bare ends in some places. The board becomes open to static and other power sources. If that water shorts an AC line then your Arduino may not alert you to anything. You might want to check your contacts (bare wire ends) for corrosion once in a while too, but that can be rubbed off.

Your IDE has example sketches to help you learn basics. Click File then Examples then choose a category to get at the examples. The Arduino site has a page for each with further explanation and pictures. If you go through sections 1, 2, 3 and 5 (please, skip 4 so you don't have to unlearn C++ Strings if you ever want to do much) and not even all the examples in 1, 2 and 3 then you will should have much less Fear than now and be able to approach projects knowing first level tools like arrays and loops as well as if and else. You will see how to read one thing and use the result of that to do another. You will be able to ask questions and get answers that will help you more.

Personally, I'd put a magnet on a float in the sump and have a cheap (50 cents) security sensor detect when it rises. That might require the float being in a piece of PVC pipe and occasional checks to see if anything is growing in it. Dirt won't affect that unless the float gets held down and the whole rig can be guarded against static and shorts. Also look into a piezo buzzer for a final stage alarm as those are harder to ignore than leds.
9  Community / Bar Sport / Re: ARM Cortex-M7 on: September 27, 2014, 05:30:09 am
I ran 4 MHz S-100 8085's with 32K at work in 1980-1983.
The cheap 6502 machines ran at 1 MHz and had 5K, 16K, 32K and up to 128K that I remember.
Throughout the 80's, especially from 86 on the hardware got faster. The XT's became AT's. C64, Amiga.
But basic business, production and productivity really didn't change. We just ran faster computing.

Honest, *most* of the programs and packages I wrote back then could have been rearranged to run on an UNO with SD, terminal and printer reasonably fast. Files are not that different from RAM, the CPU only works with so many bytes at a time and in terms of registers AVR easily beats those old CPU's, especially 6502.

Loads of RAM is nice but not necessary except to some apps like fast graphics. When I learned design, one lesson was that while high tolerances and special materials could be used it was smarter to engineer away from such needs. I took that into programming when that became part of my job, and then all. I started out on the job doing useful work on programmable TI calculators. I got the chance and a copy of BASIC BASIC because I had so much of that and knew production, and I made it work. A TI-56 has 100 20-digit memory registers and a magcard unit. having done what I did with that, I have no fear with 2K bytes of RAM and an SD card in reasonable time.

What kinds of things don't we do with AVR's? What gets shot down pretty quickly in Project Guidance?

I look at these Cortex boards and suddenly the ballpark is much bigger even with Cortex M0 and M1. Even knowing what I don't have to have, these things get me excited just because of the possibilities. Seeing the M7 and now learning that some have FPU's just does something to me.

One of those articles gave the size of a core at .1mm. I'm staggered.
10  Community / Bar Sport / Re: ARM Cortex-M7 on: September 26, 2014, 07:36:45 pm
My MEGA has 8 banks of 56K direct address external RAM on 1 card. 
But mostly for small business AR/AP/GL/PR you don't need much RAM if you have half decently fast mass storage.

If the total turn-around on what you sell is days then buying an expensive showpiece to turn a once-per 1 hour task into 5 minutes is kind of silly unless you can find other work for it. The same money in extra printers or other tools may make far more sense.
11  Community / Gigs and Collaborations / Re: Inserting Start bit and Stop Bit in a serial communicatiom on: September 26, 2014, 04:16:19 pm
You're right Nick. That is one of the standard ploys I've seen here.
I guess I'm just not used to seeing it handled properly. Good move!
12  Community / Bar Sport / Re: ARM Cortex-M7 on: September 26, 2014, 03:49:24 pm
Hobbyists? I wrote and fixed code that a few small businesses ran on back throughout the 80's on less powerful hardware. To do the same with AVR's and external parts would have to be arranged differently but still more than capable. We didn't have SD. When I started, 'we' didn't have hard drives and our 360K 5 1/4 floppies were ahead of mainstream floppies but we still ran production, did business and met payroll. AVR's are more than enough for that.
13  Community / Gigs and Collaborations / Re: Inserting Start bit and Stop Bit in a serial communicatiom on: September 26, 2014, 07:17:05 am
Hey Nick, there's nothing in radio module code about noise sources but a room with sparking gaps will affect the rate at which radio communications can be achieved. I only mention line noise because he is transmitting on power lines and those are subject to noise, sometimes a lot of noise like when heavy motors are connected directly to them.
14  Community / Gigs and Collaborations / Re: Inserting Start bit and Stop Bit in a serial communicatiom on: September 26, 2014, 07:10:37 am
You could put a band pass filter on the mains input of those two devices to remove the noise. It would have to be a passive LC filter and the components rated for mains. But you need to know the modulating frequencies used for that.

As long as you don't filter out the signal as well.
15  Community / Gigs and Collaborations / Re: Inserting Start bit and Stop Bit in a serial communicatiom on: September 25, 2014, 07:02:22 pm
How clean the power in the line itself should make a difference as to what kind of speed can be achieved. Back in the day I'd gotten industrial customers to buy Tripplite line conditioners to keep their equipment safe and stable. My UPS conditions my PC power which helps. Where I am the stuff out of the wall is spiky "dirty" as over and under VAC.

Laying signal on top of the power sine waves to pick it up elsewhere, the cleanest power will give the best results. If you don't get what you should out of those PLC's then check your power, you can do something about that.
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