Help with (assuming) 555 Circuit Designs

Thread Starter

burrism

Joined May 20, 2018
5
Good afternoon. I am a mechanical engineer who likes to dabble in electronic design, especially when it comes to upgrades and gadgets for classic cars. I was looking for an automated headlight circuit to turn the lights on/off based on the ambient light. During my research, I came across a former Painless Performance product (#63040) that not only filled my headlight needs, but it also provided several additional options that I would like to use. Unfortunately, the product has not been produced for over 5 years so there are none available.

  • Dome Light Delay and Dimming- The delay feature will delay the dome light from turning off for 20 seconds after a door is closed (switch to ground) or until the ignition is turned to the “ON” position. Once the dome light is “commanded” to turn off, it will slowly dim over 5 seconds.
  • Radio Delay- After the ignition is turned off, the Radio will remain powered for 15 minutes or until a door is opened.
  • Headlight Delay- Headlight delay will keep the headlights turned on for 30 seconds after the vehicle’s ignition has been turned off. This will only operate if the headlights were on before the ignition was turned off.
  • Headlight Chime- The Chime will sound if the headlight switch is left in the headlights “ON” or park lights “ON” position and a door is opened.
  • Automatic Headlights - Using a light sensor, this feature will automatically turn your headlights On and Off according to the light conditions the sensor reads for 10 seconds. When the headlights are on, the sensor must see bright enough light levels for 5 minutes before the headlights are turned back off. The factory headlight switch will still be operational.
  • Turn Signal Alert- The Chime will sound if the turn signal has been left on for 90 seconds.

Based on my limited knowledge of the 555 IC, I feel this would be the best route to pursue for these circuits although I am not knowledgeable enough to know how to design the circuits around them. I am hoping someone in this group can help me with designing the circuit(s) so I can build a board for my '59 Impala.

Thanks for your help and happy thanksgiving.
 

Wolframore

Joined Jan 21, 2019
2,317
Sounds more like a job for a microcontroller, too many different circuits and logic, it can be done with CMOS/555 but it would be much easier and more efficient to control them via codes. It’s a considerable amount of work in either case.
 

Thread Starter

burrism

Joined May 20, 2018
5
Thanks for the feedback. I was hoping for an easier solution. :(
Maybe I will download a program and learn how to program a PIC. or better yet, someone will volunteer to help. I am hoping to be wrong but I think the PIC coding will be final answer.

Thanks again!
 

Wolframore

Joined Jan 21, 2019
2,317
PIC or an Arduino. There’s a lot going on as well as all the circuit and wiring involved, it’s interesting. The CMOS / 555 method would be a lot more work and higher current draw. The circuit and power supply needs to survive spikes and dumps in automotive system. Onset it’s easy concept but there are challenges. Can be done. Do it one step at a time.
 

Thread Starter

burrism

Joined May 20, 2018
5
Have you messed with Arduinos? They’re pretty easy to get going
I have not but just downloaded the software. I have a week or so of quarantine/isolation coming up so I guess I will learn how to use it. Any recommendations on which Arduino board I should purchase?
 

Wolframore

Joined Jan 21, 2019
2,317
Any cheap one will do. I have actual ones and clones, only issue with clones is the FTDI chip requires you to update the driver. Instructions can be found online. Start with the blink and get to work. What you’re doing except for light measurements is pretty much a blink code. Just do simple stuff and don’t over complicate it at first. You’ll need to find better ways to blink layer as your requirements will grow with your project. There’s a lot going on.
 

AnalogKid

Joined Aug 1, 2013
9,286
To be clear, there is nothing preventing implementing each of the functions independently with 555's or other timer/logic circuits. But the original product almost certainly was based on a uC.

ak
 

Papabravo

Joined Feb 24, 2006
16,472
As a ME you are no doubt familiar with mechanical systems and their differential equations. Passive circuit components are governed by differential equations of the same form with solutions that are also identical in form. All of the 555 circuits you will ever see, besides all the ones you won't, revolve around the charging and discharging of a capacitor. Just like in those mechanical systems the solutions are exponential functions of time.
 
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