View Full Version : PLC/Programmable chip suggestions

26-03-2011, 07:36 PM
I've got a couple projects coming up that will need programmable electronics to do what I need them to.
The main features I'm looking for are-
Memory to store data, even if power is lost (can be built into the chip, or onto a memory card)
Ability to communicate via I2C bus (will be using an accurate timing chip which transmits a triggered time via I2C)
Ability to communicate to a computer for downloading data (won't really be needed if using some form of memory card)
6 digital inputs, and 4 digital outputs in addition to the above.

At the moment, for simplicity, I'm thinking CuBloc, but are there any other easy to programme/not stupidly expensive options I should be looking at?
I have used PICs in the past, but CuBlocs seem to be a bit easier to programme/implement.

Also, any suggestions for electronic forums for getting help?

26-03-2011, 08:21 PM
I think a PIC is a good option. I've used the internal EEPROM which is easy enough, and something like a PIC18F2550 has the I/O you need including USB, or serial which would be much easier to implement. If you need more memory then you can put an external EEPROM in.

There's a couple of BASIC compilers you might want to try that make programming them much easier. Still programming them in C is better.

What are the projects if you don't mind me asking?

26-03-2011, 09:09 PM
Main reason I was trying to avoid PIC was the need for a dedicated programmer and external clock signal, but a quick scan of the datasheet for the 18F2550 shows that that's not needed anymore, and they still come in good old fashioned DIP packaging (I'd rather not venture into surface mount at the moment!). I'll have a good read through the current PIC manuals during the week.

First project is a bmx/mtb start gate. I need something to control lights/beeper, switch solenoids, generate a random time delay between final ready beep and the final beep/gate release, and store the exact time the gate was released (this is where the external timing chip comes in - when gate gets triggered, so does the external timing chip, which outputs the time it was released for storage into memory/transmission to a computer).

Second project, is a lap timer with a break beam.
Third project is finish line timing to go with the first project.

To start with, and to save time/cost (need the first bit built and tested before the middle of may, although timing might be skipped for now), everything will be getting done on strip boards. If it works, I'll look at getting proper circuit boards made.

26-03-2011, 09:23 PM
Second project, is a lap timer with a break beam.

Coincidence - I started making a lap counting system with coil on model car with a big coil lying across the track. Each car has different frequency through coil allowing band pass filters to be used on the track coil to distinguish between cars and increment a counter.

I'll look at getting proper circuit boards made.

Use CNC router to make them yourself!

26-03-2011, 11:50 PM
There are quite a few RF tag systems around, but they're not needed for the type of events this is for.

I'd need a CNC router first!

27-03-2011, 08:30 PM
I've got a couple projects coming up that will need programmable electronics to do what I need them to....

...Also, any suggestions for electronic forums for getting help?

I was going to suggest CubLoc, but you said it first. Forum is somewhat underpopulated.

Could I also add: Arduino - a vast user base, very easy to program, does not prevent you from using the full power of C if necessary; (standard) AVR - though the forum is less receptive to beginner questions; finally PicAxe - very cheap, but somewhat slow. Also, there is Basic Stamp, about which I know nothing other than it exsts.

27-03-2011, 09:02 PM
Arduino looks interesting, and a quick scan of the website ticks the required boxes.

Looks like I need to decide between Arduino, CuBloc, or PIC :-/

01-04-2011, 10:42 PM
Have you looked at these:
I've used the VM1 with a touch screen for a lot of commercial machinery (which we sell them but have 27 running here that have been running 24/7 for the last 5 years, never been switched off), never had one fail, they are as capable as a PC and very easy to program (software is free and is a kind of object basic). 8000 lines of code compile to about 20kb and will interface to any thing. The controller on it's own is 57. Has ethernet capability and SD cards, RTC, I2C, encoder inputs, multi tasking etc etc. Even seen one hosting a web site! Bit more Expensive but extremely capable.

02-04-2011, 12:31 AM
I meant to update this thread to say I've ordered an Arduino starter kit, which got delivered this morning, and I'm now currently trying it for the first time!

Tom, I'll add that one to the list for any future projects that need more computing power.

02-04-2011, 04:40 PM
There a bit overkill for you're application but a lot of fun to play with. Hoping to get hold of a VM2 soon for future developments. Tom