Getting started with a timing project

[ashleyhollister]

I am a film effects technician. I have, for many years, done the timing of my high-speed events with individual digital timers. It has been in my mind for some time to try to build a multi-event programmable timer, but I have never had a good idea for this, since I am an electronics moron. I recently spoke with a friend far more learned than I about this, in the context of trying to make something using a parallel cable, and I was dismissed in a way that was barely civil. My friend said that I should be using an Aduino. I went home and looked it up on Wikipedia. La la la... here I am. What I need is advise on these questions:

Which Aduino do I need?
What else do I need?
What do I need to know?
Where will I learn that?

What I hope to be able to do is to input time-parameters in milliseconds, take signal trigger inputs, and have outputs that are of sufficient strength (perhaps 100 ma?) to trigger relays. I'd like to have about 3 input channels and about 10 output channels.
Any suggestions?

[zenwebb]

Which Aduino do I need?

There are many, many different types of Arduino boards, but the most-used, officially-support board is the Uno: https://www.adafruit.com/products/50

What else do I need?

Without knowing more about your project, I wouldn't feel too comfortable giving you a list of anything to buy at this point. I would highly recommend figuring out more details about your project before thinking about hardware or things to buy. For example, how do you plan to interface with your cameras? Is there a standard plug or connection, or are you hacking your cameras in some way? Do you know how digital camera timers work, or if there already exists a programmable timer that you can just buy for this purpose?

What do I need to know? / Where will I learn that?

See above.

Based on your last paragraph, my intuition tells me you could use an LCD and a couple of buttons to increase or decrease the 'time-parameters' visually. Then, you can connect some switching circuitry (depends on how much current you need to switch) to your cameras' interfaces. Not being a photographer, I don't know what 'signal trigger inputs' are, but you can easily take analog or digital measurements with the Arduino and utilize those values in your code.

Can you explain your project a little more, and maybe provide some relevant examples so we know what we're talking about? Also, could you tell us a little bit about your experience level, and how much electronics experience you have?

[ashleyhollister]

Well, lets see. There really is no camera interface. I use timers to control the events that the camera is shooting. All I need in terms of output is enough 5v to throw a relay. The rest is easy. I do use off-the-shelf digital timers, but I am hoping to organize things into a more structured system. I believe that you are right that I will need an LCD and a few buttons. How hard will that all be? By "signal trigger inputs" I only mean that I need to start timers by closing switches. As for explaining the project, it needs to be as flexible as possible. Every day the project is different, and what I really need is a modular timing devise.
My experience with running projects to ground is pretty high, but my experience with electronics is very low. It is quite possible that this will prove to be beyond my skill set, but that won't necessarily stop me from trying it. I' good with failure. What I really need harware-wise is enough channels.

[adafruit_support_bill]

I have, for many years, done the timing of my high-speed events with individual digital timers.

I think the first thing you need to define here is what your real-time constraints are. "high-speed" can mean different things in different domains.

All I need in terms of output is enough 5v to throw a relay.

That implies that your time constraints are more on the order of multiple-milliseconds than microseconds. That is not difficult at all with an Arduino.

What I hope to be able to do is to input time-parameters in milliseconds,

How do you need to input these parameters? Is this a device you want to write programs for, or do you need some sort of simple user interface?

take signal trigger inputs

What kinds of trigger inputs? Switches? Photoelectric sensors?

and have outputs that are of sufficient strength (perhaps 100 ma?) to trigger relays

This is pretty straightforward to do with a transistor on each output.

[ashleyhollister]

My time events are usually between 1 and 200 milliseconds, stepped in single milliseconds. I do not need microseconds. I don't have time to write programs on the set. I will need to quickly change parameters through, as you rightly call it, a "simple user interface". This should probably involve an LED and a few knobs and buttons.. Yes, switches, photoelectric sensors, hall effect sensors, noise sensors, it all changes every day. Today I was working with a laser switching a photoelectric sensor. The key for me is flexibility, because there are always new variable. Now a simple question which will reveal the depths of my ignorance. Does "14 I/O Pins (of which 6 provide PWM output) mean that I could have any combination of input and output within those numbers, or are there other constraints on this?

[adafruit_support_bill]

Does "14 I/O Pins (of which 6 provide PWM output) mean that I could have any combination of input and output within those numbers, or are there other constraints on this?

Assuming that all of your I/O is digital in nature (reading switches or other on/off type sensors and activating relays are all digital). You can use these pins any way you want. There are also 6 analog pins which can also be used for digital i/o, giving you a total of 20.

However, your user interface is going to require some pins too. You should give some thought to the design of that so you know how many pins it will take.