Need help with intermittent circuit failures - JK Flip Flops

[petrus bitbyter]

OK, try this site: http://www.jason3712.zoomshare.com/

I might post some photos on there too if I have time, so that you get the
idea of my project. But for now, I have only included the schematic. Let
me know if it's successful or not =)

Jason.

Jason,

Found the schematic. Do you really switch the power for the 555 with that
reed switch? If so it explains the problem very well. As the 555 may not be
stable immediately after power on, the 555 may miss an incoming pulse from
time to time. When switched off, the bounce of the reed contact will shake
the timer which may produce some false pulses, sometimes called spikes, to
the 4089. C5 will mask this behaviour to some extend.

I see you switch the relay and the motor using the same signal. As the
transistor is much faster then the relay, the motor will get current before
the relay has switched, but as the relay is much faster then the motor I
doubt you will see it move into the wrong direction. Nevertheless it may
produce disturbances and I advise to delay the signal to Q1 for some ms. A
couple of 4069 inverters along with an RC combination will do the trick.

Why should the monostable be triggered at power on? At power on the motor
will start to turn anyway so sooner or later you will meet the magnet.

petrus bitbyter

 

[John Fields]

OK, try this site: http://www.jason3712.zoomshare.com/

I might post some photos on there too if I have time, so that you get the
idea of my project. But for now, I have only included the schematic. Let
me know if it's successful or not =)

---
1. A 4059 is a programmable counter, not an inverter.

2. The reed switch should _not_ be used to supply power to the 555.
The 555 should be connected across the power rails and the reed
switch should only be used to do the triggering.

3. Your triggering polarity is wrong. It should be a short
negative-going spike. Here's how the 555 should be wired:
(View in Courier)


+12V-+---------+---+----+-------+------+
| | | | |8 |
[10K] [10K] +->[POT] +---+---+ |
| | | 2|_ Vcc _|4 |
+-[0.1µF]-+--------|--O|T R|O-+
| | 6| |3
| O +---|TH OUT|------
| O | 7|_ |5
SW1| +--O|D VC|----+
| +| | GND | |
| [10µF] +---+---+ [0.1µF]
| | |1 |
GND>-+------------------+-------+--------+


3. The motor drive logic is bad because when the 555 times out its
output will go low, driving U2-2 high. This will toggle the JK
and send power to the motor at the same time. Unfortunately,
power will be sent to the motor before the direction relay has a
chance to toggle, so the motor will be starting to spin up
when the relay opens, cutting off power to the motor and then,
when it closes on the other set of contacts, plugging the motor.
OUCH!

To keep that from happening, what you need to do is cut power to
the motor first, when the reed relay triggers the 555, then, when
the motor stops spinning, toggle the relay, and then reapply
power to the motor, like this:

|-->T1<--|
____ _______ _ _ ____ ________ _ _
U3-3 |________| |________|
_______ _ _ _____________
u3-1 _____________| |________ _ _


|<---T2--->|
__________ __________
U1-3 ____| |_____ _ _ ____| |______ _ _
____ _____ _ _ ____ ______ _ _
U2-2 |__________| |__________|



The trick here is to make sure that T1 doesn't go high until the
motor stops turning and to make sure T2 lasts long enough so that
RL1 changes state and all contact bouncing has ceased before U2-2
goes high and sends power to the motor.

Arguably the easiest way to do that with what you have so far is to
add another 555, like this:


+12V-+---------+---+----+-------+------+
| | | | U1 |8 |
[10K] [10K] +->[1MR] +---+---+ |
| | | 2|_ Vcc _|4 |
+-[0.1µF]-+-+------|--O|T R|O-+ U2
| | | 6| |3 1| \ 2
| O | +---|TH OUT|-----O| >---> TO U3-3
| O | | 7|_ |5 | /
SW1| | +--O|D VC|----+
| | +| | GND | |
| | [1.2µF] +---+---+ [0.1µF]
| | | |1 |
GND>-+-----------|------+-------+--------+
|
|
|
|
+12v>------------|------+-------+------+
| | U4 | |
| [1MR] +---+---+ |
| | |_ Vcc _|4 |
+------|--O|T R|O-+
| | |3 | \
+---|TH 0UT|-----O| >---> TO R2
| |_ | | /
+--O|D VC|----+
+| | GND | |
[1.5µF]+---+---+ [0.1µF]
| | |
GND>--------------------+-------+--------+

Also, to keep any kickback from the motor from hurting Q1, you could
connect two 15V Zener diodes in series opposition across the motor.

The timing for the monostable 555 is:


T = 1.4RC,


so for U1, which controls the changeover relay, you'd want a timeout
longer than the spin-down speed of the motor, say 1-1/2 seconds.
Using a 1 Megohm resistor for timing means the capacitor would have
to be:

T 1.5s
C = ------ = ------------ ~ 1.07µF
1.4R 1.4 * 1E6R

If you use an electrolytic with a tolerance of +/-10% and a resistor
with a 5% tolerance the whole thing could be off by 15% on the low
side, so to keep that from happening you'll need to increase the
capacitance by 10% and the resistance by 5% or make the cap large
enough to swamp out the whole thing. A standard capacitance value
is 1.2µF, which should do it. Checking:


T = 1.4RC = 1.4 * 1E6R * (0.9 * 1.2E-6F) = 1.512s

So that works. if you need a longer timeout increase the value of
either R or the C.

The same thing goes for U4, except that you'll want to make its
timeout longer in order to let the relay get stable before you send
power to the motor. I've set a time constant of about 2 seconds
using 1.5µF.

So that's it, except for an annoying little detail which just hit
me, and that's that the reed switch is going to bounce when it's
released. That'll confuse the circuit by making it think that it
got a valid switch closure, and may be part of the problem you're
having now. In any case, I'll post this now and a solution for the
bounce problem later on today or tomorrow.

 

[John Fields]

1. A 4059 is a programmable counter, not an inverter.

 

[John Fields]

So that's it, except for an annoying little detail which just hit
me, and that's that the reed switch is going to bounce when it's
released. That'll confuse the circuit by making it think that it
got a valid switch closure, and may be part of the problem you're
having now. In any case, I'll post this now and a solution for the
bounce problem later on today or tomorrow.

---
Here ya go. Since you had half of the JK left over, and some
inverters as well, I made a debouncer out of the JK and split the
drivers into two sections; one for the relay and one for motor
power. Make sure you disconnect R2 from U2-2 and/or U3-3 if you use
my circuit. Following the schematic is a partly fleshed out LTSPICE
simulation. Enough to see that the logic and the noise filter /
debouncer works. Enjoy!


+12V>-+-------+
| | U3B
O [0.1µF] 4027
| | 9+-------+15
SW1| <--O--+------|S1 Q1|--[1MR]--+
| 13| |12 |
[10K] +--|>1 R1|---------+
| |10| | |
GND +--|J1 | [2.2µF]
|11| _ |14 |
+--|K1 Q1|---+ GND
| +-------+ |
GND |
|
+12V>--+--[10K]--+-----[0.1µF]---+
| |
+---------|------+-------+------+
| | | U1 |8 |
[1N4148] | [1MR] +---+---+ |
| | | 2|_ Vcc _|4 |
+---------+------|--O|T R|O-+ U2
| | 6| |3 1| \ 2
| +---|TH OUT|-----O| >---> TO U3-3
| | 7|_ |5 | /
| +--O|D VC|----+
| +| | GND | |
| [1.2µF] +---+---+ [0.1µF]
| | |1 |
GND>-------------|------+-------+--------+
|
|
|
|
+12v>------------|------+-------+------+
| | U4 | |
| [1MR] +---+---+ |
| | |_ Vcc _|4 |
+------|--O|T R|O-+ U2
| | |3 | \
+---|TH 0UT|-----O| >---> TO R2
| |_ | | /
+--O|D VC|----+
+| | GND | |
[1.5µF]+---+---+ [0.1µF]
| | |
GND---------------------+-------+--------+



Version 4
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FLAG -1280 592 0
FLAG 160 -192 0
FLAG 272 -192 0
SYMBOL Misc\\NE555 96 256 R0
SYMATTR InstName U1
SYMBOL voltage -1072 384 R0
WINDOW 3 24 104 Invisible 0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR Value PULSE(0 5 1 1e-6 1e-6 1 0 1)
SYMATTR InstName V1
SYMBOL voltage -1280 384 R0
WINDOW 123 0 0 Left 0
WINDOW 3 24 104 Invisible 0
SYMATTR Value 5
SYMATTR SpiceLine Rser=0
SYMATTR InstName V2
SYMBOL res 320 176 R0
SYMATTR InstName R2
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SYMBOL cap 320 352 R0
SYMATTR InstName C1
SYMATTR Value 1.2e-6
SYMBOL Misc\\NE555 768 256 R0
SYMATTR InstName U2
SYMBOL res 992 176 R0
SYMATTR InstName R4
SYMATTR Value 1e6
SYMBOL cap 992 352 R0
SYMATTR InstName C2
SYMATTR Value 1.5e-6
SYMBOL cap -400 208 R90
WINDOW 0 0 32 VBottom 0
WINDOW 3 32 32 VTop 0
SYMATTR InstName C6
SYMATTR Value .1e-6
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SYMATTR InstName R6
SYMATTR Value 10k
SYMBOL diode -368 112 R180
WINDOW 0 43 30 Left 0
WINDOW 3 25 -6 Left 0
SYMATTR InstName D2
SYMATTR Value 1N4148
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SYMATTR InstName R7
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SYMATTR InstName A1
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WINDOW 123 0 0 Left 0
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WINDOW 0 36 34 Left 0
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SYMATTR InstName C5
SYMATTR Value 1E-7
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WINDOW 0 -53 35 Left 0
WINDOW 3 -67 62 Left 0
SYMATTR InstName R1
SYMATTR Value 100K
TEXT -1178 -160 Left 0 !.tran 0 3s 0
TEXT -1184 -128 Left 0 !.model MYSW SW(Ron=1 Roff=1Meg Vt=.5 Vh=-.4)

 

[John Fields]

On Fri, 09 Jun 2006 17:19:06 -0500, John Fields


+12V>-+-------+
| | U3B
O [0.1µF] 4027
| | 9+-------+15
SW1| <--O--+------|S1 Q1|--[1MR]--+
| 13| |12 |
[10K] +--|>1 R1|---------+
| |10| | |
GND +--|J1 | [2.2µF]
|11| _ |14 |
+--|K1 Q1|---+ GND
| +-------+ |
GND |
|
+12V>--+--[10K]--+-----[0.1µF]---+
| |
+---------|------+-------+------+
|K | | U1 |8 |
[1N4148] | [1MR] +---+---+ |
| | | 2|_ Vcc _|4 |
+---------+------|--O|T R|O-+ U2
| | 6| |3 1| \ 2
| +---|TH OUT|-----O| >---> TO U3-3
| | 7|_ |5 | /
| +--O|D VC|----+
| +| | GND | |
| [1.2µF] +---+---+ [0.1µF]
| | |1 |
GND>-------------|------+-------+--------+
|
|
|
|
+12v>------------|------+-------+------+
| | U4 | |
| [1MR] +---+---+ |
| | |_ Vcc _|4 |
+------|--O|T R|O-+ U2
| | |3 | \
+---|TH 0UT|-----O| >---> TO R2
| |_ | | /
+--O|D VC|----+
+| | GND | |
[1.5µF]+---+---+ [0.1µF]
| | |
GND---------------------+-------+--------+

 

[ehsjr]

I can't find it either.
Ed

 

[ehsjr]

OK, try this site: http://www.jason3712.zoomshare.com/

I might post some photos on there too if I have time, so that you get the
idea of my project. But for now, I have only included the schematic. Let
me know if it's successful or not =)

Jason.

In addition to John's reply, another change is needed:
you're not driving Q1 hard enough. Lower the value
of R2 from 10K to 1K.

Ed

 

[Jason S]

In addition to John's reply, another change is needed:
you're not driving Q1 hard enough. Lower the value
of R2 from 10K to 1K.

Ed

Noted. Thanks Ed =)

 

[Jason S]

Thanks guys heaps. You been a great help.
I haven't had a chance yet to try your schematic John (Petrus and ehsjr, I
have noted your observations and advice as well), but I'll let you know as
soon as I've totally rewired my breadboard...ugh.

However, do I really need to add another IC to my board (the 2nd 555)? This
board has to be as small as possible... I didn't think I'd need so much
electronics to do this simple task. Maybe 1x 556 (dual 555 IC) instead of
2x 555 would save a little more space??

By the way - in relation to the way I configured the monostable.... is it
still a bad thing to want to be able to trigger the monostable at power on
(ignoring the reed switch for arguments sake)? Assume pins 1 and 8 were
connected directly to the supply rails... so when power is turned on, the
monostable triggers automatically (due to C2). I understand the correct
method of triggering pin 2 with a negative pulse, but then I would need a
separate circuit to achieve that as well - the negative pulse. That is the
only reason why I connected the reed relay the way I did - When the magnet
comes into contact with the reed, it triggers the 555, doesn't matter how
long the reed is in contact with the magnet for. In my circuit, if I made
it so that the reed switch triggers pin 2, the 555 would freeze (on 'high')
because the motor would have turned off and stopped right in front of the
magnet indefinately. I was just wondering that's all.

The two 15V zener diodes across the motor opposite each other is critical
yeah? Is my Q1 transistor overheating because these are absent? Or because
of the motor reactivating too soon before the relay switches over??? The Q1
is rated 0.8A.

P.S: John, I really appreciate your schematics... makes it a lot easier to
understand what you are talking about =).

Ta
Jason.

 

[Jason S]

Thanks guys heaps. You been a great help.
I haven't had a chance yet to try your schematic John (Petrus and ehsjr, I
have noted your observations and advice as well), but I'll let you know as
soon as I've totally rewired my breadboard...ugh.

However, do I really need to add another IC to my board (the 2nd 555)?
This board has to be as small as possible... I didn't think I'd need so
much electronics to do this simple task. Maybe 1x 556 (dual 555 IC)
instead of 2x 555 would save a little more space??

By the way - in relation to the way I configured the monostable.... is it
still a bad thing to want to be able to trigger the monostable at power on
(ignoring the reed switch for arguments sake)? Assume pins 1 and 8 were
connected directly to the supply rails... so when power is turned on, the
monostable triggers automatically (due to C2). I understand the correct
method of triggering pin 2 with a negative pulse, but then I would need a
separate circuit to achieve that as well - the negative pulse. That is
the only reason why I connected the reed relay the way I did - When the
magnet comes into contact with the reed, it triggers the 555, doesn't
matter how long the reed is in contact with the magnet for. In my
circuit, if I made it so that the reed switch triggers pin 2, the 555
would freeze (on 'high') because the motor would have turned off and
stopped right in front of the magnet indefinately. I was just wondering
that's all.

The two 15V zener diodes across the motor opposite each other is critical
yeah? Is my Q1 transistor overheating because these are absent? Or
because of the motor reactivating too soon before the relay switches
over??? The Q1 is rated 0.8A.

P.S: John, I really appreciate your schematics... makes it a lot easier
to understand what you are talking about =).

Ta
Jason.

*** Further to this, I have redone my schematic. Please check if everything
is correct as I may have missed something or misunderstood a bit here n
there.

Try this direct link :
http://www.jason3712.zoomshare.com/...pe_editable.css&css=/lib/style/type_album.css

.... or find it manually by going to http://www.jason3712.zoomshare.com/
then clicking 'PHOTOS', 'Electronics', and clicking top (most recent) image,
"schemtaic_SL_v2".

I am yet to rewire my breadboard.

Regards,

Jason.

 

[Alan B]

True, and not yet.

But, on Windows, Paint Shop Pro can convert image formats, and on Linux,
The Gimp, so it's not all that hard.
http://www.abiengr.com/~sysop/Share/PSP412.EXE - it's shareware, but very
old, but very good for what it does.

Irfan V. 3.80 for Windows does the trick nicely. I don't like the newer
versions. And, um, thanks for the info about .gif vs. .jpg. Now it's off
to the forest to take some photos of hot babes!

 

[John Fields]

Thanks guys heaps. You been a great help.
I haven't had a chance yet to try your schematic John (Petrus and ehsjr, I
have noted your observations and advice as well), but I'll let you know as
soon as I've totally rewired my breadboard...ugh.

However, do I really need to add another IC to my board (the 2nd 555)? This
board has to be as small as possible... I didn't think I'd need so much
electronics to do this simple task. Maybe 1x 556 (dual 555 IC) instead of
2x 555 would save a little more space??

---
The second 555 isn't necessary. After thinking about it for a
while, Petrus' suggestion to use unused gates to get the delay
turned out to be a good one, so that's what I did. I've posted a
new schematic for you on abse which has that change (as well as
others) on it. After looking the schematic over, if you need a
circuit description I'll be happy to post one here.
---

By the way - in relation to the way I configured the monostable.... is it
still a bad thing to want to be able to trigger the monostable at power on
(ignoring the reed switch for arguments sake)? Assume pins 1 and 8 were
connected directly to the supply rails... so when power is turned on, the
monostable triggers automatically (due to C2).

---
And _stays_ triggered, so its output can never go low, U2-2 can
never go high, and the motor will never be able to turn!

For a 555 to operate properly, the signal on pin 2 must go more
negative than 1/3Vcc and then go more positive than 2/3Vcc before
the the output timeout period elapses.
---

I understand the correct
method of triggering pin 2 with a negative pulse, but then I would need a
separate circuit to achieve that as well - the negative pulse.

---
No, you wouldn't, all that would need to happen is that the circuit
be reconfigured. See my schematic.
---

That is the
only reason why I connected the reed relay the way I did - When the magnet
comes into contact with the reed, it triggers the 555, doesn't matter how
long the reed is in contact with the magnet for. In my circuit, if I made
it so that the reed switch triggers pin 2, the 555 would freeze (on 'high')
because the motor would have turned off and stopped right in front of the
magnet indefinately.

---
That's not true. Assuming a normally open reed switch, the way you
have it wired now keeps the 555's input low, which keeps its output
high until the magnet makes the switch, then the switch closes and
forces the outout of the 555 low until a switch bounce cause it to
start timing out again. That's one of the reasons for the source of
your problems.
---

I was just wondering that's all.

---
Maybe not critical, but you need them in there to clamp any
transients caused by a change of current in the inductance of the
motor.
---

Is my Q1 transistor overheating because these are absent? Or because
of the motor reactivating too soon before the relay switches over??? The Q1
is rated 0.8A.

---
More than likely because you're not providing enough base current to
drive the transistor into saturation. That's why Ed suggested that
you change R2 to 1K. The problem you may have with that is that
4000 series CMOS can't supply much current without going out of
rail-to-rail. I've paralleled three of the 4069's inverters in
order to circumvent that, and you should be able to drive the
transistor nicely with that "buffer"
---

 

[Jason S]

---
The second 555 isn't necessary. After thinking about it for a
while, Petrus' suggestion to use unused gates to get the delay
turned out to be a good one, so that's what I did. I've posted a
new schematic for you on abse which has that change (as well as
others) on it. After looking the schematic over, if you need a
circuit description I'll be happy to post one here.
---

--------- Hi John, I don't see the new schematic on adse =( Remember how
you couldn't see mine? Looks like the same thing is happening. Please, I
would like to see it =)
If I could get away without the need for an additional IC, I'd be happy.
But if I need it I need it... but I'll probably end up somehow wiring up a
556 rather than two separate 555's. That'd be alright wouldn't it?

---
Maybe not critical, but you need them in there to clamp any
transients caused by a change of current in the inductance of the
motor.
---

John, please confirm the correct wiring of these zeners on my schematic if
your new schematic doesn't include this section of the circuit. I'm not
100% if I understood what you meant by, "connect two 15V Zener diodes in
series opposition across the motor".

Jason.

 

[John Fields]

--------- Hi John, I don't see the new schematic on adse =( Remember how
you couldn't see mine? Looks like the same thing is happening. Please, I
would like to see it =)

---
OK, I've emailed it to you.

If you don't have access to abse it's probably because your ISP
doesn't carry abse. If you want it, let them know and maybe they'll
start carrying it.

BTW, I'm working on a version of the circuit with _no_ 555s which
looks pretty good. I'll post it to abse and email you a schematic
when I'm done. Sometime today, I think.

 

[John Fields]

---
OK, I've emailed it to you.

If you don't have access to abse it's probably because your ISP
doesn't carry abse. If you want it, let them know and maybe they'll
start carrying it.

BTW, I'm working on a version of the circuit with _no_ 555s which
looks pretty good. I'll post it to abse and email you a schematic
when I'm done. Sometime today, I think.

---
Better than that, an LTSPICE simulation follows that uses only two
chips for the logic, a "D" type flip-flop and a NOR. I used a
MOSFET bridge instead of a relay for the motor rotation reversal,
but if you want to use a relay you can hook it up like you've shown
on your schematic. Same thing for the power ON-OFF to the motor.


Version 4
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[Jason S]

---
OK, I've emailed it to you.

If you don't have access to abse it's probably because your ISP
doesn't carry abse. If you want it, let them know and maybe they'll
start carrying it.

BTW, I'm working on a version of the circuit with _no_ 555s which
looks pretty good. I'll post it to abse and email you a schematic
when I'm done. Sometime today, I think.

---
Better than that, an LTSPICE simulation follows that uses only two
chips for the logic, a "D" type flip-flop and a NOR. I used a
MOSFET bridge instead of a relay for the motor rotation reversal,
but if you want to use a relay you can hook it up like you've shown
on your schematic. Same thing for the power ON-OFF to the motor.
[snip]
John Fields
Professional Circuit Designer

Hi again John,
Thanks, I received your email with your PDF attachment. I have also added
this to my website so everybody else can see what you have posted to me, if
that's ok.

Click this link to view the schematic John Fields emailed to me :
http://www.jason3712.zoomshare.com/...pe_editable.css&css=/lib/style/type_album.css).

I rewired my breadboard and the attached circuit works quite well, although
I couldn't hook up the gearhead motor because I broke one of its terminals
=S ... I'll have to pull it apart and resolder it. Besides, I don't have
any 15V zeners on me at the moment, so I don't want to pop another BC338!
But at least I can tell what is happening by the 3 LED's, "Motor On",
"Direction A" and "Direction B". So it appears now there is that extra
delay before the motor turns back on.

I've noticed a potential problem though!!! You know how this thing pans 180
degrees and then changes direction shortly after the reed switch is
magnetized? This thing would break on me if it was left the way it is (not
the circuit, but the outer structure because it's not designed to spin
beyond 180 degrees).

- I'll give you an example:
Imagine the motor is turning in Direction "A", and the reed switch just made
contact with the magnet. Then I shut down the whole circuit intentionally
(at this stage, it has already panned 180 degrees, which is the max). If
you then turn the circuit back on, *sometimes* the motor starts to spin in
the same direction (A) it was before - when it should be turning the
opposite direction (B) straight away. So somehow the circuit will need to
know that it reached the end from the previous time and should be turning in
the correct direction. I'm not sure how this will need to be hooked up, but
maybe a second reed switch is needed (one for each direction)???

Other than that it seems to be working fine. I can't wait to see your next
version John.... no 555!

Regards
Jason.

 

[John Fields]

I've noticed a potential problem though!!! You know how this thing pans 180
degrees and then changes direction shortly after the reed switch is
magnetized? This thing would break on me if it was left the way it is (not
the circuit, but the outer structure because it's not designed to spin
beyond 180 degrees).

- I'll give you an example:
Imagine the motor is turning in Direction "A", and the reed switch just made
contact with the magnet. Then I shut down the whole circuit intentionally
(at this stage, it has already panned 180 degrees, which is the max). If
you then turn the circuit back on, *sometimes* the motor starts to spin in
the same direction (A) it was before - when it should be turning the
opposite direction (B) straight away. So somehow the circuit will need to
know that it reached the end from the previous time and should be turning in
the correct direction. I'm not sure how this will need to be hooked up, but
maybe a second reed switch is needed (one for each direction)???

 

[Jason S]

John!
Thanks for the once-again modified schematic.
Fantastic to see less IC's ... from three down to only one single IC now,
the 74HC02 NOR gate! As you know, IC's take a lot of room on a board, and
my board needs to be as small as possible.
I haven't got some of the parts readily available to modify my breadboard
prototype, but when I get my hands on them (within the next couple of days)
I will try it out and see what happens! I'll get back to you to let you
know how I went. Fingers crossed it won't need any more mods =)

I will include your mod on my website incase anyone wants to see it (for
those who can't access it via ABSE like I can't).

Thanks
Jason.

 

[Jason S]

Hi John,

I built your latest schematic on my breadboard. Works really well, except
for one thing.... There is no 1 sec delay for the motor before the relay
switches over. So what it's doing is turning off the motor and switching
relay contacts at the same time, then half a second later the motor turns
back on.

Regards
Jason.

 

[John Fields]

Hi John,

I built your latest schematic on my breadboard. Works really well, except
for one thing.... There is no 1 sec delay for the motor before the relay
switches over. So what it's doing is turning off the motor and switching
relay contacts at the same time, then half a second later the motor turns
back on.

---
Good!, that's how it's supposed to work.

The reason the relay switches over when the motor stops is because
there's no reason for it not to and it saves a timer.

Think about it... once power to the motor is cut off, all you need
is the delay for the motor to stop turning before you supply power
to the motor again, so when the direction-reversing relay switches
over is immaterial.

If you need some extra time before power is again applied to the
motor just adjust R10.