I'm back - a new circuit for the mini-golf course

Lance, is there more to this circuit than one sensor? How does the system discern between the ball going in on the hole on the 2nd, 3rd or further strokes? Is there a sensor at the tee-off area of the final hole which is high and then rest of the circuit is live? (i.e. - first stroke would be taken from the tee off area, sensor plate? circuit would be momentarily complete letting the rest of the circuit go live such that if the ball would pass the IR sensor while the person was still standing in the tee off area = hole in one)

 

There's no problem with detecting a short pulse. You can use any kind of latch or flip-flop. You can make one from two transistors (Google bistable multivibrator), logic gates (Google SR latch or SR flip-flop) or an IC such as the CD4013, CD4027, or 74(HC)74.

The voltage on your white wire should go all the way up to 5V when the light is blocked from the sensor. If it's only going up to 0.6V there must be something wrong - perhaps the light is too bright and isn't being fully blocked. If that's the voltage you measure on a multimeter when you drop a ball through the pipe, it's probably not the actual "high" voltage on the white wire; the multimeter does not respond to the peak value of a very short pulse. Try holding the ball in the pipe instead of dropping it through.

And as chopnhack says, AFAIK you'll need some way to detect whether the ball is a hole-in-one.

 

I suspect that the 19th hole allows you only one shot. It either goes in the hole, or goes away somewhere else, ending your game.

Bob

 

Do you have a pic of the original boards? I'm curious as to what's on them.

I 2nd the suggestion for a SR (aka bistable) flip flop. Another option is a relay wired to latch itself: have the 5V pulse from the sensor energize a relay, and then the relay contacts themselves keep the relay (and buzzer) on. A normally-closed pushbutton would break the circuit to deactivate the alarm.

If you go the relay route, you'll need a transistor to amplify the current since you'll only get a couple mA from the phototransistor. If you go the flip-flop route, use a comparator or Schmitt trigger buffer to condition the signal and make it more logic-friendly. A simple RC filter would help with noise immunity--you don't want the alarm going on everytime the air conditioner cycles on or off. How far away are the 19th hole sensors from the clubhouse where the alarms are?

Also, does he want a single alarm for both holes or a separate one for each?

If the circuit used a 12V power supply, and you're expecting 5V at your sensors, you'll need to use a 5V regulator (especially if you're going to use logic ICs), or you could increase the value of your current limiting resistors to use a 12V circuit with transistors/relay.

 

A relay with a 12v coil and SPST or SPDT contacts is fine. It doesn't have to be heavy duty or anything, just enough to power the buzzer and the relay coil, so even a small relay with 1 amp contacts will be plenty.

 

It's possible that the phototransistor circuit won't have enough current to energize the relay by itself (looking at your other thread, it has a 10k resistor). You'll probably need a transistor to amplify the current at the clubhouse end. I'll be out all day but can post a schematic later, or someone else here will.

 

BASIC Stamp..OMG! That was the first microcontroller I ever played with. I have one of those development boards kicking around.

For what the circuit does, it's huge overkill (unless it does other things besides just sound a buzzer when someone sinks a hole on the 19th). A latching relay will do the same thing without requiring firmware.

What's that ELK-800 amplifier used for? An amplifier for the "buzzer"?

 

Here's a quick schematic I drew up. It's not the neatest but it gets the point across.

Q1 amplifies the signal from the phototransistor and energizes the relay. Once it's energized, the contacts ground out the circuit so that the buzzer and LED stay lit until momentary normally-closed button SW1 is pressed.

R3 adds additional current limiting for the IR LED in the hole, since it'll be seeing 12v instead of 5V. Alternatively, increase the 220 ohm resistor in the hole to something higher like 470 or 680 ohms.

D1 is a flyback diode to protect the transistor from back EMF when the relay turns on/off. R2 limits current through the LED. I marked Wht, Grn, and Red for the wires going to the hole sensor.

If the buzzer is an electromechanical one (I prefer piezo buzzers), put another diode across the buzzer terminals with the cathode toward the 12V side, like the one on the relay.

There's no filtering in this circuit, a capacitor or two in a few places may help reduce noise or false triggers.

 

It's hard to know how old the setup is, as BASIC Stamps have existed since the 1990s are are still made today.

So, it could be 20 years old, or just a few years. But the added music and lights at the hole explains why they used a microcontroller in the first place. The flashing lights and music are probably generated in firmware (written in a dialect of Basic) and the chip plays the sequence when the hole sensor is triggered.