XOR at 12V and a few amps.

George Herold · Sep 25, 2012

First off this question is of academic interest only.

So I needed to hook up the a 4 wire trailer connector onto our Toyota
van. (previously we had a Ford van.) My brother warned me that the
foreign cars use a 5 wire lamp indicator system. (There are separate
bulbs for the brake and turn signal. The trailer uses only one bulb
for both brake and turn.)
I first thought I could just put the two (brake, turn) lines together
with diodes. But I then realized this wouldn’t work with both the
brake and the turn signal on.
What I needed was a XOR connection between the lines.
both off, bulb off
one on, bulb on
both on, bulb off
So is there a way to do this with some diodes, transistors,
resistors?
I’ve been unable to see the way to an answer. (I haven’t tried
google, that’s too easy and this is more fun.)

Any ideas?

Oh, I solved the problem by going to carquest and buying a wiring
harness for ~$50. But say I’m stuck on a desert island with only my
parts box.

George H.

Tom Biasi · Sep 25, 2012

First off this question is of academic interest only.

So I needed to hook up the a 4 wire trailer connector onto our Toyota
van. (previously we had a Ford van.) My brother warned me that the
foreign cars use a 5 wire lamp indicator system. (There are separate
bulbs for the brake and turn signal. The trailer uses only one bulb
for both brake and turn.)
I first thought I could just put the two (brake, turn) lines together
with diodes. But I then realized this wouldn’t work with both the
brake and the turn signal on.
What I needed was a XOR connection between the lines.
both off, bulb off
one on, bulb on
both on, bulb off
So is there a way to do this with some diodes, transistors,
resistors?
I’ve been unable to see the way to an answer. (I haven’t tried
google, that’s too easy and this is more fun.)

Any ideas?

Oh, I solved the problem by going to carquest and buying a wiring
harness for ~$50. But say I’m stuck on a desert island with only my
parts box.

George H.

You can make an XOR with relays. I'm not sure this is how to do your job
though.
I could show you a diagram but that would be the same as you going to
Google.

Tom

George Herold · Sep 25, 2012

You can make an XOR with relays. I'm not sure this is how to do your job
though.
I could show you a diagram but that would be the same as you going to
Google.

Tom- Hide quoted text -

- Show quoted text -

OK thanks Tom, I'll google xor with relays. But yes I was thinking
about power transistor. (I've got lots of them)

George H.

George Herold · Sep 25, 2012

If you're stuck on that proverbial desert island, then there won't be
anyone there to see your brake lights. So just don't plug the wiring in.

--
Tim Wescott
Control system and signal processing consultingwww.wescottdesign.com- Hide quoted text -

- Show quoted text -

Yeah and very few roads to boot.
(there's one in every crowd :^)

George H.

George Herold · Sep 25, 2012

There are some designs online, you must include the word schematic to
find them.

Several ideas, probably more complex than needed:http://www.designnews.com/document.asp?doc_id=217805&dfpPParams=htid_...

A patent listing with schematic:http://www.google.com/patents/US6232722- Hide quoted text -

- Show quoted text -

Thanks, I was hoping for something without relays.

The patent looks like there is a separate 12V power line coming in to
power the transistors. (But I didn't read it.)

George H.

petrus bitbyter · Sep 25, 2012

"George Herold" <[email protected]> schreef in bericht
First off this question is of academic interest only.

So I needed to hook up the a 4 wire trailer connector onto our Toyota
van. (previously we had a Ford van.) My brother warned me that the
foreign cars use a 5 wire lamp indicator system. (There are separate
bulbs for the brake and turn signal. The trailer uses only one bulb
for both brake and turn.)
I first thought I could just put the two (brake, turn) lines together
with diodes. But I then realized this wouldn’t work with both the
brake and the turn signal on.
What I needed was a XOR connection between the lines.
both off, bulb off
one on, bulb on
both on, bulb off
So is there a way to do this with some diodes, transistors,
resistors?
I’ve been unable to see the way to an answer. (I haven’t tried
google, that’s too easy and this is more fun.)

Any ideas?

Oh, I solved the problem by going to carquest and buying a wiring
harness for ~$50. But say I’m stuck on a desert island with only my
parts box.

George H.

Well, guess you have right, left and brake. Assuming right and left
blinking, for the right bulb you get:

B R L | Rb
------|---
0 0 0 | 0
0 0 1 | 0
0 1 0 | 1
0 1 1 | -
1 0 0 | 1
1 0 1 | 1
1 1 0 | 0
1 1 1 | -

If you can have both right and left on, blinking "alarm" in Europe, you get
for both bulbs:

B R L | Rb Lb
------|------
0 0 0 | 0 0
0 0 1 | 0 1
0 1 0 | 1 0
0 1 1 | 1 1
1 0 0 | 1 1
1 0 1 | 1 0
1 1 0 | 0 1
1 1 1 | 0 0

This way you will get B xor L for the left bulb and B xor R for the other,
just as advertised.

So I suppose the schematic below will do the trick. Although I do not seem
to remember I saw it before, I'm sure not to be the first one that drew it.
Think I do not have to explain it for this public

brake -->|-------------+
Schottky |
left -->|-------------+
|
right -->|-------------+
|
.-.
( X ) Lb
'-'
|
+------+------------------+
| |
| |
___ |/ ___ |/
brake--|___|-----+---| left---|___|-----+---|
| |> | |>
| | | |
| | | |
___ |/ | ___ |/ |
left---|___|---| | brake--|___|---| |
|> | |> |
| | | |
| | | |
| | | |
GND-----------+-----+-------------------+-----+
created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de

petrus bitbyter

George Herold · Sep 25, 2012

"George Herold" <[email protected]> schreef in berichtFirst off this question is of academic interest only.

So I needed to hook up the a 4 wire trailer connector onto our Toyota
van. (previously we had a Ford van.) My brother warned me that the
foreign cars use a 5 wire lamp indicator system. (There are separate
bulbs for the brake and turn signal. The trailer uses only one bulb
for both brake and turn.)
I first thought I could just put the two (brake, turn) lines together
with diodes. But I then realized this wouldn’t work with both the
brake and the turn signal on.
What I needed was a XOR connection between the lines.
both off, bulb off
one on, bulb on
both on, bulb off
So is there a way to do this with some diodes, transistors,
resistors?
I’ve been unable to see the way to an answer. (I haven’t tried
google, that’s too easy and this is more fun.)

Any ideas?

Oh, I solved the problem by going to carquest and buying a wiring
harness for ~$50. But say I’m stuck on a desert island with only my
parts box.

George H.

Well, guess you have right, left and brake. Assuming right and left
blinking, for the right bulb you get:

B R L | Rb
------|---
0 0 0 | 0
0 0 1 | 0
0 1 0 | 1
0 1 1 | -
1 0 0 | 1
1 0 1 | 1
1 1 0 | 0
1 1 1 | -

If you can have both right and left on, blinking "alarm" in Europe, you get
for both bulbs:

B R L | Rb Lb
------|------
0 0 0 | 0 0
0 0 1 | 0 1
0 1 0 | 1 0
0 1 1 | 1 1
1 0 0 | 1 1
1 0 1 | 1 0
1 1 0 | 0 1
1 1 1 | 0 0

This way you will get B xor L for the left bulb and B xor R for the other,
just as advertised.

So I suppose the schematic below will do the trick. Although I do not seem
to remember I saw it before, I'm sure not to be the first one that drew it.
Think I do not have to explain it for this public

brake -->|-------------+
Schottky |
left -->|-------------+
|
right -->|-------------+
|
.-.
( X ) Lb
'-'
|
+------+------------------+
| |
| |
___ |/ ___ |/
brake--|___|-----+---| left---|___|-----+---|
| |> | |>
| | | |
| | | |
___ |/ | ___ |/ |
left---|___|---| | brake--|___|---| |
|> | |> |
| | | |
| | | |
| | | |
GND-----------+-----+-------------------+-----+
created by Andy´s ASCII-Circuit v1.24.140803 Betawww.tech-chat.de

petrus bitbyter

Excellent! Thanks.
Just one thing. Why do you have the right tied in at the top through
the schottky? This doesn't seem to hurt anything.
But doesn't help either. (that I can see.)

George H.
(

petrus bitbyter · Sep 25, 2012

"George Herold" <[email protected]> schreef in bericht

"George Herold" <[email protected]> schreef in
berichtFirst off this question is of academic interest only.

So I needed to hook up the a 4 wire trailer connector onto our Toyota
van. (previously we had a Ford van.) My brother warned me that the
foreign cars use a 5 wire lamp indicator system. (There are separate
bulbs for the brake and turn signal. The trailer uses only one bulb
for both brake and turn.)
I first thought I could just put the two (brake, turn) lines together
with diodes. But I then realized this wouldn’t work with both the
brake and the turn signal on.
What I needed was a XOR connection between the lines.
both off, bulb off
one on, bulb on
both on, bulb off
So is there a way to do this with some diodes, transistors,
resistors?
I’ve been unable to see the way to an answer. (I haven’t tried
google, that’s too easy and this is more fun.)

Any ideas?

Oh, I solved the problem by going to carquest and buying a wiring
harness for ~$50. But say I’m stuck on a desert island with only my
parts box.

George H.

Well, guess you have right, left and brake. Assuming right and left
blinking, for the right bulb you get:

B R L | Rb
------|---
0 0 0 | 0
0 0 1 | 0
0 1 0 | 1
0 1 1 | -
1 0 0 | 1
1 0 1 | 1
1 1 0 | 0
1 1 1 | -

If you can have both right and left on, blinking "alarm" in Europe, you
get
for both bulbs:

B R L | Rb Lb
------|------
0 0 0 | 0 0
0 0 1 | 0 1
0 1 0 | 1 0
0 1 1 | 1 1
1 0 0 | 1 1
1 0 1 | 1 0
1 1 0 | 0 1
1 1 1 | 0 0

This way you will get B xor L for the left bulb and B xor R for the other,
just as advertised.

So I suppose the schematic below will do the trick. Although I do not seem
to remember I saw it before, I'm sure not to be the first one that drew
it.
Think I do not have to explain it for this public

brake -->|-------------+
Schottky |
left -->|-------------+
|
right -->|-------------+
|
.-.
( X ) Lb
'-'
|
+------+------------------+
| |
| |
___ |/ ___ |/
brake--|___|-----+---| left---|___|-----+---|
| |> | |>
| | | |
| | | |
___ |/ | ___ |/ |
left---|___|---| | brake--|___|---| |
|> | |> |
| | | |
| | | |
| | | |
GND-----------+-----+-------------------+-----+
created by Andy´s ASCII-Circuit v1.24.140803 Betawww.tech-chat.de

petrus bitbyter

Excellent! Thanks.
Just one thing. Why do you have the right tied in at the top through
the schottky? This doesn't seem to hurt anything.
But doesn't help either. (that I can see.)

George H.
(

So you can use the "power" for the right bulb as well.

petrus bitbyter

petrus bitbyter · Sep 25, 2012

Maybe. If so you can solve that problem I suppose

petrus bitbyter

George Herold · Sep 25, 2012

Oops. That's right. No worries this gives me a circuit to start
with.

I think I can jsut flip the whole thing over, use pnp's and get rid of
the
schottky. Or p-channel Fets?

George H.

petrus bitbyter · Sep 25, 2012

John Fields said:
---
Maybe.

I seem to recall from the stony ages that a bimetallic flasher was
turned on when the directional switch was energized, and the lamp
which was flashed was the one the switch pointed to.

How is it done now?

Suppose it depends on the age of the vehicle. Older ones may stil use
bimetallics, newer for sure use electronics. But does it matter? Especially
when one side of the bulb is hard-grounded the other side gets a pulsing
voltage from the turn and a constant voltage from the brake. Originally
meant for two different bulbs but to be combined by the circuit for one
bulb.

petrus bitbyter

George Herold · Sep 26, 2012

I did turn signals with power bipolar back in the mid-60's... figure a
10X surge when the bulb turns on. (*)

Or retrofit your trailer with LED's ;-)

(*) I even resorted to a pre-warm current technique before giving up
and going to SCR's... in the sequential T-bird lighting.

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon athttp://www.analog-innovations.com| 1962 |

I love to cook with wine. Sometimes I even put it in the food.- Hide quoted text -

- Show quoted text -

Thanks Jim... this is just of academic interest.... I was wondering
how to make an XOR function out of a few parts. JF's link and
petrus's circuit have 'shown me the way'.

George H.

petrus bitbyter · Sep 28, 2012

"George Herold" <[email protected]> schreef in bericht

Oops. That's right. No worries this gives me a circuit to start
with.

I think I can jsut flip the whole thing over, use pnp's and get rid of
the
schottky. Or p-channel Fets?

George H.
"I think I can jsut flip the whole thing over, use pnp's and get rid of
the schottky. Or p-channel Fets?"

Nope. An open contact does not sink current. Right, left and brake can only
source current.

petrus bitbyter

George Herold · Sep 28, 2012

"George Herold" <[email protected]> schreef in bericht
Oops. That's right. No worries this gives me a circuit to start
with.

I think I can jsut flip the whole thing over, use pnp's and get rid of
the
schottky. Or p-channel Fets?

George H.

"I think I can jsut flip the whole thing over, use pnp's and get rid of
the schottky. Or p-channel Fets?"

Nope. An open contact does not sink current. Right, left and brake can only
source current.

petrus bitbyter- Hide quoted text -

- Show quoted text -

Ouch, that's right.
'scratch, scratch'
guess I better look at that patent circuit again.

George H.

petrus bitbyter · Sep 28, 2012

"George Herold" <[email protected]> schreef in bericht

"George Herold" <[email protected]> schreef in
bericht
Oops. That's right. No worries this gives me a circuit to start
with.

I think I can jsut flip the whole thing over, use pnp's and get rid of
the
schottky. Or p-channel Fets?

George H.

"I think I can jsut flip the whole thing over, use pnp's and get rid of
the schottky. Or p-channel Fets?"

Nope. An open contact does not sink current. Right, left and brake can
only
source current.

petrus bitbyter- Hide quoted text -

- Show quoted text -

Ouch, that's right.
'scratch, scratch'
guess I better look at that patent circuit again.

George H.

Nope once more. Guess the circuit below will do the trick as well. But, as
others stated already, the power transistor needs to be a real heavy duty
type as the inrush current of those bulbs can easily be five to ten times
the nominal current.

brake -->|-------------+
Schottky |
left -->|-------------+
|
right -->|-------------+
|
|
___ |<
+--|___|-----|
| |\
| |
+-------------------+-----+ |
| | |
| | |
___ |/ ___ |/ |
brake--|___|-----+---| left---|___|-----+---| .-.
| |> | |> ( X )
| | | | '-'
| | | | |
___ |/ | ___ |/ | |
left---|___|---| | brake--|___|---| | |
|> | |> | |
| | | | |
| | | | |
| | | | |
GND-----------+-----+-------------------+-----+--------+
created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de

petrus bitbyter

petrus bitbyter · Sep 28, 2012

petrus bitbyter said:
"George Herold" <[email protected]> schreef in bericht

Ouch, that's right.
'scratch, scratch'
guess I better look at that patent circuit again.

George H.

Nope once more. Guess the circuit below will do the trick as well. But, as
others stated already, the power transistor needs to be a real heavy duty
type as the inrush current of those bulbs can easily be five to ten times
the nominal current.

brake -->|-------------+
Schottky |
left -->|-------------+
|
right -->|-------------+
|
|
___ |<
+--|___|-----|
| |\
| |
+-------------------+-----+ |
| | |
| | |
___ |/ ___ |/ |
brake--|___|-----+---| left---|___|-----+---| .-.
| |> | |> ( X )
| | | | '-'
| | | | |
___ |/ | ___ |/ | |
left---|___|---| | brake--|___|---| | |
|> | |> | |
| | | | |
| | | | |
| | | | |
GND-----------+-----+-------------------+-----+--------+
created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de

petrus bitbyter

If you want to go for relays, you will not need a patented circuit I
suppose. See below.

VCC
Left +
| |
| o
_|_ \ left
|_/_|- \
| o \o
| | |
| + +
| \ /
=== X
GND / \
+ +
| |
Brake | |
| o /o
_|_ /
|_/_|- / brake
| o
| |
| .-.
| ( X )Lb
=== '-'
GND |
|
===
GND
created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de

For Vcc you can use the three Schottkys but keep in mind that they need to
be able to handle the inrush current. Otherwise you will need a wire from
the dashboards fuse panel.

petrus bitbyter

Tom Biasi · Sep 28, 2012

Snip..

If you want to go for relays, you will not need a patented circuit I
suppose.

petrus bitbyter

Go for automotive relays. They are proven for temps and environment.

Jasen Betts · Sep 29, 2012

First off this question is of academic interest only.

So I needed to hook up the a 4 wire trailer connector onto our Toyota
van. (previously we had a Ford van.) My brother warned me that the
foreign cars use a 5 wire lamp indicator system. (There are separate
bulbs for the brake and turn signal. The trailer uses only one bulb
for both brake and turn.)
I first thought I could just put the two (brake, turn) lines together
with diodes. But I then realized this wouldnâ€™t work with both the
brake and the turn signal on.
What I needed was a XOR connection between the lines.
both off, bulb off
one on, bulb on
both on, bulb off
So is there a way to do this with some diodes, transistors,
resistors?
Iâ€™ve been unable to see the way to an answer. (I havenâ€™t tried
google, thatâ€™s too easy and this is more fun.)

Any ideas?

Oh, I solved the problem by going to carquest and buying a wiring
harness for ~$50. But say Iâ€™m stuck on a desert island with only my
parts box.

a couple of form b relays each wired to disconnect the other circuit...

if you can read ascii ladder logic.

---|BRK|-+----( A )-------------
|
`----|/B|---+--(OUT)---
|
.----|/A|---'
|
---|IND|-+----( B )-------------

you'll want two of those, one for each side.

Jasen Betts · Sep 29, 2012

if you can read ascii ladder logic.

---|BRK|-+----( A )-------------
|
`----|/B|---+--(OUT)---
|
.----|/A|---'
|
---|IND|-+----( B )-------------

you'll want two of those, one for each side.

there's a simpler way if you have a +12 supply at the point where you
want to put the circuit just one relat is enough, coil wired between
the INDicator and BRaKe lines contacts switching +12V to the trailer.

Jamie · Sep 29, 2012

Jim said:
On Sat, 29 Sep 2012 14:16:54 -0500, John Fields

[snip]

Since Toyota's have been described as "5-wire", I presume that's...

Brake Left Brake Right
Turn Left Turn Right
Ground

So each side is independent and "Turn" (flashing) trumps "Brake"
(steady).

...Jim Thompson

---
Mine works like that and provides hazard mode flash as well, with
three relays instead of four:

. +12
.BRAKE---+ |
. | O K1
. [COIL]. . ./
. | O->/ <-O
. GND | NC |
. | |
. | +----|--[LLAMP]--+
.LFLASH>-+ | | | |
. | | O K2 | GND
. [COIL].|. . .\ |
. | O-> \<-O
. GND | NO |
. | |
. | +----|--[RLAMP]--+
.RFLASH>-+ | | | |
. | | O K3 | GND
. [COIL].|. . .\ |
. | O-> \<-O
. GND NO

Are both "Brake" lamp circuits wired together? I have a wiring
diagram for my Q45... I guess I should open the manual and see how
Infiniti does it.

...Jim Thompson

Booboos. We fret over brake and turn, but what about tail/running
lights?

...Jim Thompson

Click to expand...

Around her, in Arizona-land, you're required to have at least one
"running" light or a "flag" ;-)

I'm wondering if "5-wire" isn't actually...

Running
Brake
Left Turn
Right Turn
Ground

...Jim Thompson

Click to expand...

I found this...

http://tinyurl.com/44m6pmu

...Jim Thompson

Right, something I stated way back at the start of this tread and I
took that from memory.

So, it is true then, if it's on the internet it must be true
otherwise beware of information coming elsewhere.

Jamie

Moore's Lobby Podcast

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