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Creating a timer that performs an action

by dunar21
Tags: action, creating, performs, timer
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Apr21-11, 10:55 PM
P: 3
Hello, I am not even a novice at electrical engineering. I am a web designer and a programmer (Actionscript 3.0 and PHP - also MySQL for my websites' databases-). Anyway, I am attempting to create a series of circuits that count items moving on a conveyor belt with an IR sensor, and runs a motor in one direction after a certain count and then in the opposite direction after a repeat of that count. So, say for every five items, once the fifth item breaks the IR connection and sends the fifth pulse to the counter, I need the counter to run a motor in one direction(and to switch directions after every 5th count) and begin counting the next item as number 1. I have an IR circuit that sends pulses to this counting circuit kit I bought at an electronics store: (This kit uses the IC described on the datasheet at How would I arrange the circuit to run a motor (about 9V to the motor) after every 5 counts. I would need it to start the next count at 1 instead of using a count to reset and then the following count set to 1. So, as the 5th count runs the motor that same connection would have to reset the clock instead of the 6th count resetting it. It would be nice to have a switch that allows me to switch between a 5 or a 6 count, but once I see how to do one, it shouldn't be that difficult to make a switch that runs a similar process at a different count. Any help or advice would be greatly appreciated. Thank you in advance.
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Apr22-11, 12:51 PM
P: 595
Without getting too deep into this...

It sounds like you've got your sensor figured out, but you need a simple micro-controller to do the counting and motor control. There's hobbyist sorts of things like the Basic Stamp and Arduino, or you can spend a few months becoming an embedded engineer and use a MicroChip PIC or many others.

The main problem is running your motor in both directions. For this you need an "H-bridge" driver, which could lead to another few months of electronic engineering degree study. There are commercial boards and motor controllers for automation and such, e.g., I have used these guys products:
Evil Bunny
Apr22-11, 01:24 PM
P: 237
Swapping the leads on a dc motor reverses the direction of rotation. So if you didn't want to get into the H bridge thing, you could either:

1. Wire up two seperate batteries (with the leads wired opposite each other at the input) to a transfer switch (if such a thing exists on this scale) or...

2. Wire up two different motors to the same conveyor. Each would run the opposite way.

You'd still need the microcontroller to do the counting and send the appropriate output signalling, of course

Apr22-11, 01:37 PM
P: 2,536
Creating a timer that performs an action

Quote Quote by Evil Bunny View Post
Swapping the leads on a dc motor reverses the direction of rotation.
Not necessarily. This is true only on a motor with permanent magnet fields.
Evil Bunny
Apr22-11, 01:53 PM
P: 237
good point... I think most smaller motors will work this way. You should check first.
Apr23-11, 01:54 PM
P: 3
Thanks for your help guys. It seems that the circuit I linked to is programmed in a specific way and the software is proprietary, so there is no real way to modify that particular circuit to suit my needs. There have to be many IC circuits, though, that will allow me to send a series of pulses and then to simply have current flow after a certain amount of pulses, reset and repeat. I'm google hunting for the solution now. Thanks again for the assistance.

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