Timer baseball feeder circuit

[DaveK]

I have a 3v dc motor that turns at a slow rpm. It has a rubber wheel
that comes in contact with a baseball. This allows the baseball to be
pushed in to a pitching machine. The ball waits in line to be driven
by the motor. I would like to be able to turn the motor on but have a
time delay of approximately 15 sec before it runs continuously. I will
have a limit switch to turn off the motor after the last ball has been
pitched. What type of circuit would be needed to produce this? I know
this is pretty basic but I’m very new to this. I can read schematics,
build circuits and have experience with electronic components but
having the proper circuit would make things very easy for me. Can some
one make a schematic that I can use to accomplish this? Any
information would greatly be appreciated. Thank you in advance for
your time.

Dave K

 

[DaveK]

The timer is a CMOS 555, and if you can tell us how much current the
motor draws, one of us can select an appropriate MOSFET for Q1.

                                              ____
.        | <--O--+-----+-------+-------+-----+--O  O--+
.        |       |     |       |       |     |K  S2   |
.3V>-----O S1    |     |      8|       |  [1N4001][MOTOR]
.             [100K] [1M]  +---+---+   |     |        |
.                |     |  2|_ Vcc _|4  |    +--------+
.                +-----|--O|T     R|O--+     |
.                |     |  6|       |   |     D
.                |     +---|TH  OUT|---|---G NCH
.                |     |  7|_      |3  |     S Q1
.             [100nF]  +--O|D  7555|   |     |
.                |    +|   |  GND  | [10K]  |
.                |  [10µf] +---+---+   |     |
.                |     |      1|       |    |
.GND>------------+-----+-------+-------+-----+

---
Aaarghhh!!!

Jumped the gun on that one, sorry...

This one's right, I think.  

S1 is the motor ON switch and S2 is the motor's limit switch, assuming
it's normally closed while the motor's running.

.     | <--O--+-----+-------+-------+---+----+            
.     |       |     |       |       |   |   |          
.3V>--O S1    |     |      8|       |   |    |            
.          [100K] [1M]  +---+---+   | [10k]  |            
.             |     |  2|_ Vcc _|4  |   |    |            
.             +-----|--O|T     R|O--+   |    |
.             |     |  6|       |   |   |   S
.             |     +---|TH  OUT|---|---+--G PCH
.             |     |  7|_      |3  |        D Q1
.          [100nF]  +--O|D  7555|   |        |  ____
.             |    +|   |  GND  | [10K]      +--O  O--+
.             |  [10µf] +---+---+   |        |K S2   |
.             |     |      1|       |    [1N4001]  [MOTOR]
.             |     |       |       |       |        |
.GND>---------+-----+-------+-------+--------+--------+

The way it works is that as soon as S1 is made, the timer will output
a 15 second high-going pulse which will keep Q1 turned off.

Then, if S2 is made when the timer times out and pulls the gate of Q1
low, Q1 will switch on and allow charge to flow through the motor
until S2 opens.

When that happens, you'll need to open S1 before you load more balls
into the machine and override the limit switch.

Then, after the balls are loaded, to start the cycle anew, just turn
S1 ON.

About 15 seconds later it should start spitting out balls again.

JF- Hide quoted text -

- Show quoted text -

JF,

Thank you so much for you response. There is nothing on the motor
indicating amp draw. It has many gears to deliver high torque which I
think lower the amp draw. The transformer puts out 3vdc at 500ma. I
hope that is enough info to pick out the correct MOSFET.

I took your schematic into WORD and used "courier new" because for
some reason plain courier was not an option, so in-turn the schematic
looks just like the one on this page. I have used schematics that were
sent to me awhile back and they worked out great in WORD. I must have
had the option of using courier instead of courier new.

I believed I could figure something out one way or another, unless you
have any suggestions. The way it is now I’m just not smart enough to
decipher it totally.

Thanks again for your prompt response