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New user/Project help

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dfn

New Member
First line is just to hi from a new user.

Its been a while since I did electronics (Army/Signals TeleTech Sys) and have forgotten most of it, so I would be greatful for any assistance.

I'm looking to put together a faily simple circuit:-

Electro-magnet, timer, switch, sound module on a 12v supply.

Position 1 of the switch should cause the magnet to be live, position 2 should start the timer sequence and end with cutting the supply. During the count down sequence I would like the sound module to say a couple of words (recording) and have 3 beeps before the magnet goes dead, the whole sequence should last about 5 seconds.

Hope this all makes sence and I would appreciate for any help.
 
I would do it with a microcontroller myself. But you would need a programmer and software to program it, but it would be simple.

The speaking part will add some cost to the project. Is it required? Have a microcontroller, a relay, a momentary switch, LED, beeper.

Push button once (magnet/relay and LED on), push button again and timer starts (blink the LED) when the at 4 seconds beep, 5 seconds drop the magnet/relay and turn out the LED.
 
Thanks mramos1. Yes the speaking part is required. The project is for a BMX home practice start-gate, so needs to be cheap and cheerful.

Next question, microcontroller, programmer and software to program it.

Thanks
 
Do you have a laptop? And does it have a parallel print port. You can do all this on a laptop. Program will be pretty simple, and less parts, just a $1500 computer is required. waitfor a key out to printer port to lock gate waitfor a key pause 4000 playwavfile (1 sec wav file) out to printer to release magnet. On the microcontroller, you can get a programmer cheap and there are a couple free programming programs on the forum. Use mikcrobasic to write he code (simple and free trial version)
 
Yes I have a laptop, but I think it will be safer if I put it in a box. I fall off too many times for the laptop to be safe.:( Though the gate is really for my son :eek:
 
It was a quick solution.. I would use a microcontroller (12F675). Maybe google for a "pic voice record and playback circuit" to start, then pic relay driver and pic led interface. All the parts are out there. If was not so busy, I would draw it up and write the code. But I have a lot of projects today. Do you have the magnet part on the gate already? Where are you located?
 
Once again mramos1 thank you. I have had a look at the code and as you suggested it should not be too difficult. No I do not have a magnet as yet and I am in the UK (near Manchester). You have done all but draw the circuit for me and I appreciate your time and help. Just have to give myself a headache for the next couple of days trying to remember all the things I learned about 15 years ago.
 
Things have changed and you will love the PIC chips. Probaby think of many other projects.

You probably do not need the LED since you will have speech, the quality will vary based on the way you go. The relay part will be a resistor to a transistor to drive the coil (and a diode to block the spike), so it is not too hard a project.

Nigel Goodwin posted a good link a few days ago, you can search for it. Lots of pic projects (I think at microe.com). But do not get locked into the 16F84, they are old. The 12F675 is an 8 pin low power PIC.

You can build a programmer for 20-30 US.. I have an old P16PRO40, but they are many on the internet. Nigel also has free programming software on his website. Oh, duh, you can start learning there and get most of what you need.
 
I was thinking of using something like the ISD2532P 32-sec Record/Playback IC. Thanks for the links
 
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