Separate Brake Light From Turn Signal

[eTech]

Interesting. Well, without getting to complex is that an issue with this circuit? Would that prevent me from synchronizing the trailer circuit?

The trailer circuit needs to be "tuned" to the "on time" of the blinker signal. So, as long as the square wave test signal faithfully reproduces the blinker signal, the trailer circuit can be tuned and should work.

You mean at pin 3 of the 555 output? If so perhaps adding a transistor to increase the output so it can drive the trailer circuit. If that's the concern.

Yes pin 3, but the trailer circuit inputs draw very little current (~1mA), so not really a concern.

 

[ThomsCircuit]

I added test points, that I believe I have in the correct place (pot pins 2 & 3), to measure the resistance. I am also assuming that I just need one turn signal on to test then adjust that pot until output led goes off then its done. just set the other pot to match.

 

[eTech]

I added test points, that I believe I have in the correct place (pot pins 2 & 3), to measure the resistance. I am also assuming that I just need one turn signal on to test then adjust that pot until output led goes off then its done.

Yes.

just set the other pot to match.

Well...we hope its that easy.

 

[shokjok]

No.
If one side is blinking and the brake is applied, then that side remains blinking and the other side goes on steady with the brake.
The brake does not cancel the blinking.

I had this issue with my bike trailer taillight interface in 1987. I worked out an X-OR circuit using analog relays or DPDT switches on the handlebar. My brake switch input feeds both NC relay contacts, the flasher output feeds both NO relay contacts, while the relay arms feed the tail lights. The relay coils are fed from SPST switches in a block assembly on the handlebar. Both the brake switch and the handlebar switch blocks are separately fed from the battery positive terminal; the negative terminal connects to the frame via a perforated strip connected to battery negative terminal clamp. It's been working for more than thirty years now; photos sent on demand.

 

[ThomsCircuit]

I had this issue with my bike trailer taillight interface in 1987. I worked out an X-OR circuit using analog relays or DPDT switches on the handlebar. My brake switch input feeds both NC relay contacts, the flasher output feeds both NO relay contacts, while the relay arms feed the tail lights. The relay coils are fed from SPST switches in a block assembly on the handlebar. Both the brake switch and the handlebar switch blocks are separately fed from the battery positive terminal; the negative terminal connects to the frame via a perforated strip connected to battery negative terminal clamp. It's been working for more than thirty years now; photos sent on demand.

Neat-O. Sure love to see your work. I was just working on a turn signal/ brake light simulator so I can test the circuit on the bench rather than from the truck. It's basically 6 push buttons to simulate each scenario.

 

[eTech]

Neat-O. Sure love to see your work. I was just working on a turn signal/ brake light simulator so I can test the circuit on the bench rather than from the truck. It's basically 6 push buttons to simulate each scenario.

View attachment 146890

D2 is backwards

 

[ThomsCircuit]

D2 is backwards

Thank you.

 

[ThomsCircuit]

D2 is backwards

I had the relay connected wrong. The coil has a fixed polarity

 

[shokjok]

You could be lazy and do what is done on the Conch Tour Train.
On this:-

https://flic.kr/p/jzbeSm

the centre brake light just came on when either side stop/tail light came on. That meant that the centre light flashed when either turn signal was working, unless braking when it came on steadily whether a turn signal was on or not.
You could use two diodes or a relay to do that.

There's something similar like this, on a smaller scale in my city, known as multi-user pedicabs: "Grab and Go".
Needing only tail lights and a safety triangle - they're pedal powered, not motorized - these pedicabs can take up to eight riders ( four per side) down the city streets while the operator controls a steering wheel and brake pedal. The riders also determine their speed and route; only operating during summer months. Photos on a lost cellphone.