Electronics Factory Bells

I have been asked to investigate a soloution for automaticall ringing a bell at break times in a factory. My first approach was looking at dedicated soloutions, with built in atomic clocks and lcds displaying the date and time. These are an expensive and overkill soloution. This got me thinking about relay cards.

I have never really explored this area and this seems like a fun way to start.

Could somebody reccomend a hardware/software soloution that would enable me to connect upto 4 bells to a serial/com/usb port and enable them at certain times of the day.

I was thinking about something like this one at
http://www.audon.co.uk/som1.html

But not being familiar with the software don't know how easy it would be to schedule the bells.

I would greatly appreciate any help or pointers you can provide.

Cheers

 

Hi Hackstar,
The link you were referring to is a commercial unit, I'm not to fimilar with it, but I would guess that would be what you are looking for.

What I have is a diy solution using the parallel port. Most of the ideas are from here:

http://www.epanorama.net/circuits/parallel_output.html

See under the title:
Compact 8 channel output driver
and you'll find a simple example circuit using the ULN2803 chip. Subsitute the
LEDs for relays and then link each of the bells to a relay.

For software, see under the title:
Ready made control software
I use KemoM125 kit (Relais Timer). It's a simple software where you can program when each relay turns on and for how long.

Hope this helps.
ARM

 

I can offer a few solutions to this, but I need to have an idea of the budget you have to spend. Personally I would try to avoid using a PC for this task.

 

I agree. Think about it, any cheap digital-clocked central heating controller can switch on twice a day to the second, some four times a day. It's easy to rig switch-on to a timed bell. How many breaks are there?

 

if you have a PC with a free parallel port nearby this is easy as hell..

take a look here though if ya wanna go USB:

http://www.electronickits.com/kit/complete/data/vek8055.htm

buffer those ouputs and whack a relay on each one and you got yourself a answer...

 

One timer relay with presettable 1-10 second delay on power on.
One electronic timer with 24 hour clock, days of the week and program points at least double the break ammount (on and off for each break)

Or if you can find one, a 24 hour/7 day timer as above, but that can program seconds.

 

use a sprinkler timer. I have one that cost me $30, and can be set for intervals as little as 1 minute, 4 times a day.

 

A 1 minute long signal would be kind of annoying thou...

 

A 555 one-shot would cut that time down for another $ or 2. One would be needed with most (cheap) commercial timer methods.

Nice links, though, ARM

 

but hey! its cheap, and prebuilt. Also, it can handle power outages (got a battery), and runs on 24 VAC, which is perfect for the bell.

 

Thanks Arm

I have decided to give the circuit a try, just finishing it off now. I think this is the easiest soloution.

Just out of interest why do people reccomend avoiding a PC for this?

 

I doubt you'd find a commercially available atomic clock, which would be slightly overkill.
Then again I doubt that's what you meant.

Avoiding a PC seems like the best idea, unless you're also using the PC for something else that means it's left on all day.

 

The workforce will be really peed off if there's a BSOD just before snaptime.

 

it dosen't make sense to use a computer that costs £50+ to do something that electronics can do for £5 with change.

 

But if you have a room ful of servers, one of wich happens to be a time and attendance Server, then surely this is the answer coupled with the £1.50 circuit posted above.

 

You use a server instead of a timeclock?

 

I work in industrial automation and I woudn't use the PC for this task. I would use a cheap PLC (Programable Logic Contrtoller) and sychronise its clock to the servers clock over a RS232 or ethernet connection. The key point in industrial applications is that the system is relaible and simple to modify. A basic PLC will start around £100.

A PLC system would use a industry standard programming lanuage like ladder logic that any conrol engineer could modify at at later date. Whereas a bespoke system on a PC would require a software specialst to modify it.

In the short term a PLC may apper to be more expenive but it has long term benefits.

 

I would have a look at the Telemecanique Zelio range of smart relays. These are relatively cheap simple PLCs. They have inbuilt clocks and the programming software (ladder logic ) is free to download from thier website.

Have a look at this link to the Zelio smart relay web site, on this you will find out everything you need to know about one.

http://www.telemecanique.com/WEBKITS/Automation/ZELIOLOG/ENUS/index.htm