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need help Building a replacement timer for a coin op machine

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kjmann

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I have an Arcade Machine that had an electronic Timer in it that I need to replace. The Time sets 5 Minutes for every Coin inserted and shows the countdown on a 3 digit LED Display. if you insert a coin in the middle of a countdown, it just adds another 5 minutes to the time that is left.

When the time is counting down it turns on a relay to make a single connection for a signal to the controls. when the timer is at zero. the relay is off.

I need help to build something like this. Can Anyone Give me an Idea? I'm not a great Electronics person so there are some things that I just don't know how to do. =)

Sal
 
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So how do you know the timer is bad and not something else?
 
That timer function is somewhat complex and not easily done with discrete components, so it's probably best done with a microprocessor. But, of course, you would need to learn some programming skills. The easiest way, I believe, is a microprocessor that uses the Basic language, such as one of the Stamp units from Parallax, which have built-in Basic interpretors. They can be readily programmed by connecting the module to your computer.
 
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Say you're aiming at up to 3 digits...what happens if I put in 3 coins,
or 2 coins when I still have time left. Does it "max" to 9:59?? Does it
just max the minutes (e.g. to 9:23 if I had 2:23 remaining). Since
you're doing what sounds like a whole board replacement, is the
display on that board? If the display isn't can it's board be altered to
accommodate 4 digits? Must it display as minutes and seconds, or
would 300 seconds per quarter do???

Why? I'm thinking about the idea of 2 counters (mm:ss). In this
format, you'll need to monitor the binary codes from the counters
for each segment of the timer, through a multiple or sets of OR
gates (so when they are all low <out of time>, the output will be a
low <presuming the relay is grounded and has it's positive turned
on/off>). The counters would have to be up/down (only the minutes
would if the seconds stay the same <re utilizing 4 digits [who would
put 20 quarters in at once?], and if only 3 digits <re maxing at
9:59> both counters would have to be up/down (MUCH more
complex to max the seconds to 59!!!). If it has to stay 3 digits, how
about keeping the seconds the same and ripping off the patron? (if
they have 7:01 left a quarted would raise it to 9:01...).

One circuit would be the :59 countdown, that when it reaches
zero, if the minutes timer is zero, it would stop and trip the relay. If
the minutes weren't zero, it would count one down on that timer.
Since you would also be using the minute counter to add time, the
up/down control on it would need to always be down. But, when a
coin is inserted, the up/down would need to go to up, and a circuit
would send 3 clock pulses in (to add three minutes) and then turn
the minute counter back to down.

So, you're looking at three aspects...a second counter that if at
zero, will continually monitor the minutes counter (if it's
zero, hold the relay on, but if not will not hold the relay on and will
start counting down from 59, which will also trip the minutes
counter to count down one (whenever the seconds go from :00 to
:59). The clock input is disabled by the ORs that monitor ALL digits.
The second aspect is the minutes counter, it's down controlled as
previously specified, and it's up controlled by the quarter circuit.

This is quite complex, but if you give details re my questions re
how it is desired to operate (rollup of the seconds - yuk!, maximized
count, etc.) and the limitations of your display board, I (and/or
someone else) might be able to help you out. Of course, this is if
you can solder, make protoboards and most importantly,
understand clocks, binary code, LED drivers & general electronics...
 
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Say you're aiming at up to 3 digits...what happens if I put in 3 coins,
or 2 coins when I still have time left. Does it "max" to 9:59?? Does it
just max the minutes (e.g. to 9:23 if I had 2:23 remaining). Since
you're doing what sounds like a whole board replacement, is the
display on that board? If the display isn't can it's board be altered to
accommodate 4 digits? Must it display as minutes and seconds, or
would 300 seconds per quarter do???

Why? I'm thinking about the idea of 2 counters (mm:ss). In this
format, you'll need to monitor the binary codes from the counters
for each segment of the timer, through a multiple or sets of OR
gates (so when they are all low <out of time>, the output will be a
low <presuming the relay is grounded and has it's positive turned
on/off>). The counters would have to be up/down (only the minutes
would if the seconds stay the same <re utilizing 4 digits [who would
put 20 quarters in at once?], and if only 3 digits <re maxing at
9:59> both counters would have to be up/down (MUCH more
complex to max the seconds to 59!!!). If it has to stay 3 digits, how
about keeping the seconds the same and ripping off the patron? (if
they have 7:01 left a quarted would raise it to 9:01...).

One circuit would be the :59 countdown, that when it reaches
zero, if the minutes timer is zero, it would stop and trip the relay. If
the minutes weren't zero, it would count one down on that timer.
Since you would also be using the minute counter to add time, the
up/down control on it would need to always be down. But, when a
coin is inserted, the up/down would need to go to up, and a circuit
would send 3 clock pulses in (to add three minutes) and then turn
the minute counter back to down.

So, you're looking at three aspects...a second counter that if at
zero, will continually monitor the minutes counter (if it's
zero, hold the relay on, but if not will not hold the relay on and will
start counting down from 59, which will also trip the minutes
counter to count down one (whenever the seconds go from :00 to
:59). The clock input is disabled by the ORs that monitor ALL digits.
The second aspect is the minutes counter, it's down controlled as
previously specified, and it's up controlled by the quarter circuit.

This is quite complex, but if you give details re my questions re
how it is desired to operate (rollup of the seconds - yuk!, maximized
count, etc.) and the limitations of your display board, I (and/or
someone else) might be able to help you out. Of course, this is if
you can solder, make protoboards and most importantly,
understand clocks, binary code, LED drivers & general electronics...

Well, The Clock Can Be 4 Digits if one wanted. It needs to have an ability to beep when the counter gets to 20 seconds. Every quarter should give the Timer 5 Minutes, even if the time has not run out yet.
 
It's 5 minutes and I started writing about 3 minutes, but I still
have a "Q" (or 2) I didn't get answered. "Every quarter should
give the timer 5 minutes", means it adds 5 minutes to the
exisiting count, or accelerates the timer up to 5 minutes and/or
the next 5 minute multiple up from current time remaining?
"Every quarter should give the timer 5 minutes" sounds like
the timer never goes beyond 5 minutes...Do you mean every
quarter should ADD five minutes? Beeping is just another
little circuit, maybe also with flashing the display? Must the
display show MM:SS or could it simply do seconds only (a full
decimal count) which would make the circuit even easier (and
if the timer maxes at 300 might not be a big deal to the patron)?
 
It's 5 minutes and I started writing about 3 minutes, but I still
have a "Q" (or 2) I didn't get answered. "Every quarter should
give the timer 5 minutes", means it adds 5 minutes to the
exisiting count, or accelerates the timer up to 5 minutes and/or
the next 5 minute multiple up from current time remaining?
"Every quarter should give the timer 5 minutes" sounds like
the timer never goes beyond 5 minutes...Do you mean every
quarter should ADD five minutes? Beeping is just another
little circuit, maybe also with flashing the display? Must the
display show MM:SS or could it simply do seconds only (a full
decimal count) which would make the circuit even easier (and
if the timer maxes at 300 might not be a big deal to the patron)?

Every Quarter ADDS 5 minutes to the Existing count no matter where the count is at that moment.

the display can show just Seconds only (full decimal Count is Fine)

the timer should max at 9999 (using 4 digits display) or 999 (using 3 digit display)
 
Three 4-bit counters would give you a maximum count of 4095. The circuit would require a 1 second clock, three 4-bit up/down counters with preset (jam) inputs, three 4-bit adders, and three binary to 7-segment display drivers. One of the adder inputs would be the output from the counters and the other would be a fixed binary value of 300 (to add 5 minutes to whatever the count is). The output of the adder would go to the counter preset inputs. Thus a coin would trigger the circuit to cause the counter preset inputs to be enabled for one clock and add 300 seconds to the count. If the preset inputs are asynchronous (not clocked) then clocked latch buffers would need to be added to the preset inputs to avoid a race condition.
 
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