Is Arduino good for me?

Hi

I would like to buy an Arduino board but first I want to be sure that I can use it for my purpose :slight_smile:

I need a fast booting device (fast, talking about being online in less than a second) that can handle input/output devices and can be completely controlled over network - no USB. In an ideal world I would be able to save my input data to SRAM and there would be a batterybackup so it can detect events even when 'off'.

What do you think, could I use it for these things?

Thanks!

Most likely. Can't talk about the networking stuff but the rest sounds resonable. Research your SRAM requirements carefully as it is a limited resource for most harvard type microprocessors.

Lefty

Close... I took my UNO with the Arduino Ethernet Shield about 3 seconds to come up from a cold start and begine to serve a web page. The ethernet shield has status leds that were all on after about 3 seconds.

Battery backed up sram could be done with a added chip, I don't know if it could be done with the uP. From what I have read Arduino's don't like to sleep. Can only be woken up with a reset... As far as handling i/o I'm sure you would be up for that in the one second range or less.

Kevin

Stijn, could you tell us more about what the application should do, what your expectations are ?

The 1280 chip on the Mega has the ability to address external memory and the pins are brought out to the headers. So in theory it's possible to address as much SRAM as you like.


Rob

"From what I have read Arduino's don't like to sleep. Can only be woken up with a reset... "
That is flat out wrong. You shouldn't post misinformation like that.
I have a remote control that puts itself to sleep after transmitting a button press, then wakes via external interrupt on any keypress to send that key out. Was pretty easy to do once I realized that I was missing interrupt.h at the top of the sketch.

Thank you all for your replies.

The problem I'm facing with IO boards on my PC is when I'm running heavy software my PC is missing input signals because of its load. The signals are less than 100ms and the software (.NET) is skipping some.

I'd like to create a device which will perform all IO handling for me, e.g.: if I send (via network) the command that it should send 1000 pulses from 100ms to a certain output it should do it. If power goes down while sending, it should recover and send the remaining part. On the other hand if it gets input signals, it should count them and tell me afterward over the network (TCP IP stack present, not just a webserver?) how many pulses it received from which input.

As I understand it you need a gadget that will

a) Accept commands that tell it to produce X pulses on Y output(s).
b) Record the number of pulses on Z input(s) and report the values when asked.
c) Pick up where it left off if there is a power failure.

Is that the case?

Next question, why would there be a power failure? And why can't the gadget just have a battery backup?

It's not trivial to recover from a power failure and I doubt the Arduino could do it alone as you need to detect the failure and have enough time to do some house keeping before the lights go out. Doable but not I would think without some external circuitry.

Then you need to have some non-volatile storage, you can use the EEPROM but it has a limited endurance so that depends on how often you send the commands and how often you receive pulses. Otherwise there are various non-volatile options external to the Arduino.


Rob

Graynomad,

Your list is correct.

About the battery backup, this would be perfect if possible. The problem is not that the power could get lost, if it is lost it should still read pulses and remember/save them. (think about security switches on a locker, even without power they still have to be able to remember that someone opened the door when there was no power). Is a batterypack easy to implement and if so, can it detect when running on power or when on battery?

It does need to save stuff, mainly integers. Ideally the device that gets connected to it over network would say hey I'm new, tell me what I need to know here.

Thanks

Thanks CrossRoads for the correction on the sleep mode. Something I read online, didn't try for my self.

What I read is like a great deal of information on these forums, to be taken with a grain of salt.

Regards,
Kevin

What I read is like a great deal of information on these forums, to be taken with a grain of salt.

Unless I post it where you should use the whole shaker of salt, sea salt works best by the way. :wink:

Lefty

Stijn,
You should look into battery charger chips. Maxim-ic.com makes a bunch, you can install a couple of Li batteries (7.4V for example) and hook up a charge control/monitor chip that will keep it topped off, then switch to it for power if the main power is lost.
How many mAH of battery you hook up will determine how long it will keep running while main powe is lost.

Ok gents, thanks for all information! I'll try to work my way through it!

Great to see how eager people are to help here!