Digital I/O and Relay board - DR51

[Treetop]

http://www.industrologic.com/dr51prod.htm

The Industrologic DR51 is a specialized single board computer that is easy to program and easy to connect to external signals. Its two 10 amp relays, eight logic level I/O signals (with keypad connector), and serial port make it an ideal interface for many industrial control, access control, and home automation applications. It can even be used as a universal keypad encoder and key to RS-232 converter.

Price: $69

I have yet to use anything like this, so I guess my question is; thoughts? Price?

 

[Treetop]

Quoted from miked @ proximis forums:

Got the controller in the mail today, and had a chance to play around with it. Overall, I'm very pleased! It's a solid little unit.

There's only one somewhat minor downside, and that is that the Tiny Basic programming language is more limited than I had thought. The instructions say that you're limited to variables A,B,C,D,E,F,G, and that's well enough. But then they give you some examples on conditionals:

IF A<>B 20 ;go to 20 if a does not equal b
IF A=1 30 ;go to 30 if a equals 1

So, I just naturally assumed that other variable conditionals would work, too, like:

IF B=1 20

Or

IF C<>B 30

But no go. The If statement is really an "IF A" statement, as the variable A has to be your first operand. The second operand can only be a number, a string, or the variable B. So no "IF A=C", for instance.

What this does is force you to reserve the variables A and B as sort of registers (which I imagine is exactly what they are -- direct mappings of registers of the proc to BASIC variables). In my application, I am constantly switching out variables C and D for A, so that I can test these variables.

That is, there is no dynamic memory in the controller -- you get a bit of flash mem, for the program, and the 7 registers of the proc, mapped to variables A->G.

So, my only big concern is that, although there's plenty of memory for what I need to do with a single controller, in terms of program size, I may run out of variables to store the status of things, because you really only have five variables, since A and B have to basically be reserved. I've already "used up" C and D, so I have 3 left, E, F, and G. What I will have to do after that is to start using flash mem for the variables, but that adds another layer of complexity.

In all, it's a great little controller -- I just wish it had a *bit* of DRAM!

 

[electron]

thanks for sharing, that's pretty interesting.

 

[Tim]

I have personally used the Kit74, which can be purchased at many sites online. The kit cost me $33 and had 8 (I think) relays. One site I know sells them is http://www.kitsrus.com and for software I run FFHC, which was designed for the Halloween use, Frightmare Forest Haunt Controller it stands for, however it can be used for anything. I did an animated Christmas display with it last year, using 2 kits and for inputs I used jumpers, no input circuits as the webpage of the software writer shows. I was in on the beta testing of the original, so I'm somewhat biased, but it works well and is easy for beginners to program and use. Check http://halloween.sitenation.com/site/view/article/1018551761 for more information on the software, and Kit74's.