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.

 

[shokjok]

View attachment 145809

Found This. I understand most of this. The input is on the right, output on the left. I have all but the darlington 2N6388. Could I use a TIP122 & 142? It's what I have.

Thank you in advance.
T.B.

I saw this circuit in a past issue of Radio-Electronics magazine. the idea behind my bike trailer design, and part of my challenges to patent applications using microcontrollers and tilt switches ( obsolescence and successor units). My design uses relays and switches; modified for a handlebar unit to eliminate the PCB entirely.
I repaired Duraspark electronic voltage regulators by installing a TIP125 or TIP127 Darlington transistor that feeds the alternator FIELD input, to great results. The 1.5-volt drop in the Darlingtons results in an amber-glowing bulb.

 

[ThomsCircuit]

I saw this circuit in a past issue of Radio-Electronics magazine

I have been so busy working on another project. Last night we were hit pretty hard by Helene but have restored power and cleaned up most of the mess. I am still a novice and i attempted to make ETech's version on a breadboard but it did not work. I'm convinced I did not interpret the schematic correctly so tonight I'm going to remake it with a fresh pot of coffee.

 

[shokjok]

This is my original circuit. Several years ago, I replaced the transistors and resistors with a relay, wired similar to the tail light wiring, after the reverse lights glowed yellow or orange from reduced voltage ( <10V). Since its inception in 1987, my tail light circuit on a wallet-sized PCB has flawlessly worked in all weather conditions. I don't use it below -10C/ 14F.
The 1A fuse to the 2.5W monaural radio was upgraded to a 4A fuse for a 12W stereo radio.

 

[EvanDuke]

This is my original circuit. Several years ago, I replaced the transistors and resistors with a relay, wired similar to the tail light wiring, after the reverse lights glowed yellow or orange form reduced voltage feed. Since its inception in 1987, my tail light circuit on a wallet-sized PCB has flawlessly worked in all weather conditions.
The 1A fuse to the 2.5W monaural radio was upgraded to a 4A fuse for a 12W stereo radio.
View attachment 147233

Are 1A fuses still in use?

 

[shokjok]

No. 1A fuses kept blowing, replaced with suitable fuses for each circuit.

 

[ThomsCircuit]

Been trying to bread board and test the schematic from post #92. with no success. When I power it up and provide 12v to both left and right inputs and i get 11.6v from the drain on (pin2) of irf5305. But within a few seconds the drain drops slowly to zero. if I touch/bend, even just graze, the jumper cable connected to pin 3 of MC14538 and pin 6 of 4048, the output returns to 12v until I let go then it slowly returns to zero again. I've changed the jumper but the condition continues. Each time I graze the wire the process takes 5-6 seconds to go from 12v to zero. Oddly enough, the condition is consistent. Now with 12V at both inputs the drain should be 12v and remain at 12v. The only other condition that will cause the drain to go high is if both inputs flash.

I actually believe i have the bread board correct but i do need help solving this condition so I can move on. How its supposed to function is the drain should be at 12v when both inputs get a steady 12v or both flash. Any other condition the drain should be zero.
I appreciate any help solving this.

T.B

 

[eTech]

Check all +12V and ground connections with a voltmeter. Make sure they are all connected.

 

[ThomsCircuit]

Check all +12V and ground connections with a voltmeter. Make sure they are all connected.

Thank you. I believed it had to be that. Even though I have checked and double checked and then checked again I will add additional grounds, and especially more local, close grounds (pin to ground rail) instead of daisy chain grounds and minimize grounds using the long jumper wires.

I must say this has been the most challenging schematic to breadboard.

 

[ThomsCircuit]

Check all +12V and ground connections with a voltmeter

I have made changes and slightly improved things (MC14538) was reading 11.65v now 12 but the issue still exists. I also notice it happens between pin (MC14538 pin13 - 4048 pin13) as well as (MC14538 pin3 - 4048 pin6)

If i hold either of the two connection wires mentioned above the output (pin2 @ irf5305) stays on @ 11.70v. once i let go the light goes out after 6 seconds.

I'm not all that sure if I am reading the drain correctly. if the led is off it reads 10.40v. if I make the led turn on it reads 11.70v. I have the negative probe on the drain and positive on the 12+ rail

I have also changed the power supply and checked continuity in many areas. I added additional jumpers wires to improve ground connections and connected IC chips directly to 12V instead of from the cathode of 5818.
EDIT: 4048 IS POWERED AFTER 5818.

I want to add that your schematic did not have pin numbers on MC14538 so I may have interpreted them incorrectly on mine Post 98.

I have both var resistors set at 240k
-------------------------------------------------------------------------------------------
Some voltage readings

 

[eTech]

I have made changes and slightly improved things (MC14538) was reading 11.65v now 12 but the issue still exists. I also notice it happens between pin (MC14538 pin13 - 4048 pin13) as well as (MC14538 pin3 - 4048 pin6)

If i hold either of the two connection wires mentioned above the output (pin2 @ irf5305) stays on @ 11.70v. once i let go the light goes out after 6 seconds.

I'm not all that sure if I am reading the drain correctly. if the led is off it reads 10.40v. if I make the led turn on it reads 11.70v. I have the negative probe on the drain and positive on the 12+ rail

I have also changed the power supply and checked continuity in many areas. I added additional jumpers wires to improve ground connections and connected IC chips directly to 12V instead of from the cathode of 5818.
EDIT: 4048 IS POWERED AFTER 5818.

I want to add that your schematic did not have pin numbers on MC14538 so I may have interpreted them incorrectly on mine Post 98.

I have both var resistors set at 240k
-------------------------------------------------------------------------------------------
Some voltage readings
View attachment 147284

View attachment 147285

Looks like U1A/B pin numbers are incorrect on your schematic(s).

I've added the pin numbers to my schematic in post #92.

 

[ThomsCircuit]

Looks like U1A/B pin numbers are incorrect on your schematic(s).

Hmm, I wonder what a difference that might make? I'll get that squared away this evening.