Counter/ Timer Circuit

I=92m a baseball coach at a high school and when we use our pitching machine our players want to hit more balls than they should. I would like for an alarm to go off after a pre-determined amount of pitches. The machine has an arm connected to a wheel that rotates. Each full revolution equals one ball pitched. I would like to count each revolution (pulse) of the wheel either by a limit switch or even a reed switch with a magnet on the wheel. Maximum pitches would be somewhere around 10. There is 110 vac at the machine so I can run most any dc voltage through a transformer to run a circuit. I have played around with the 4017 counter/divider and the 555 timer but I don=92t seem to be getting anywhere. What would be the correct type of circuit to use for this type of application? I=92m not real experienced with electronics but I can follow a schematic and build a circuit. I would have to have a complete schematic in order for me to do this. I=92m not sure how much time it would take to make a schematic of this sort but any information would greatly be appreciated.

Thank You for Your Time Dave

I would be incined to point you to one of the easy microcontrollers - the PICAXE. It's programmed in a dialect of BASIC, so you may already have been exposed to it. If not, the chip is aimed at education (late elementary and up) in the UK.

The big advantage would be the ease of changng the number of cycles allowed (via a Sony IR remote control) and the ease of changing the type of sensor: mechanical switch, optical switch, magnetic switch (including the Hall effect chips).

The startup expense would be under $50.

I can almost guarantee that you will find "bells and whistles" to add to the design once you have the basics working.

The home site is here:

There are several US suppliers:

They have a VERY active support forum:

I'm in Georgia, near Atlanta. If you're close by, I can work with you on getting a design that works. Working from pictures and approximate measurements may not work as well...

John

Thank You for Your Time Dave

Hello Dave,

You could use the 555 as a "one shot" oscillator, one pulse per revolution and the 4017 to divide down the to the right count. I've just experimented with the 4017 and I think the Q9 output will give you a count of 10. That output could be used to trigger another 555 as a time delay for the alarm( time on). Then a transistor and an alarm of some sort.

Shaun

Allelectronics sells a LED chaser kit that has 10 LEDs, a 555 and a 4017 plus a few other components for < $7.00. You could easily modify that for your application. Either eliminate the 555 entirely and use a switch + debounce circuit to clock the 4017, or reconfigure the 555 to a one shot and trigger it from the switch. (Essentially, that uses the 555 as the debounce circuit.)

You'll most likely want to connect the 4017 output to a transistor and use the transistor to drive the alarm. Post details on the alarm you intend to use - if you have access to ABSE a schematic can be posted there.

As already pointed out, a PICAXE (or a PIC or other microcontroller) would give you greater flexibility, but you have to contend with the learning phase and initial cost for a programmer. If you have the time and the interest, learning to use a PICAXE/PIC/whatever is worthwhile.

Ed