Cant see any rationale in such design, but why not to meditate about 555?

The goals are intended to bring out the structural choices people make in building practical circuits. The stated constraints (versions) are to create a context that forces those choices along certain lines but not according to method of doing it.

I am not sure I understand the actual constraints, if there are any.

I think you missed:

There are no unstated constraints.

Whichever direction the designer chooses is completely permissible. The explicit constraints include the given BoM, the circuit's function, and the versions of each circuit (e.g.: minimum parts count).

It is precisely how people choose to approach it that is of interest. The circuits have no hidden problems to solve, and clever hacks are not required. Instead, it's intended to see how people on AAC choose to build thing.

All of this said, it appears to be an abject failure. Useless save for the lesson that it didn't work as hoped (which is worth something).

 

Well, my first and foremost "design philosophy" is never constrain myself to unsuitable requirements.

And like a lot of people won't spend time trying to make something work that can be made much easier with just a few adjustments.

So, you have learned something about my "design philosophy" without my taking the challenge.

 

All of this said, it appears to be an abject failure.

If the LED was a red type which would allow the parameters of each circuit to be practical might have made a difference.

 

If the LED was a red type which would allow the parameters of each circuit to be practical might have made a difference.

if that actually makes a material difference to anyone, it’s fine to use.

Here’s an alternative. Note that \(\mathsf{ I_f }\) is only 1mA.

 

If the LED was a red type which would allow the parameters of each circuit to be practical might have made a difference.

I totally agree, the blue LED makes the design process very tricky, and it's not a fun or elegant problem to solve.
Nothing interesting happens trying to boost 2.7 Volts to 3.2 Volts, it's just a pain. The best solutions might revolve around LED driver chipset solutions that will be very specific and esoteric.

 

If I had a 3V battery, and needed an indicator - I wouldn't choose a blue LED. I'd use a red one, so it would run from the battery.
And if I wanted to light up a blue LED, I'd use three 1.5V cells.

 

I’m afraid that the point of this challenge has been completely lost.

However, if it causes anyone to choose to participate, and the intended value, I have added a candidate LED in a post above.

It is a very high efficiency red LED with \(\mathsf{ V_f }\) of 1.7V at a \(\mathsf{ I_f }\) of 1mA. It has a max average \(\mathsf{ I_f }\) of 20mA, and peak of 300mA.

 

I’m afraid that the point of this challenge has been completely lost.

Not on everyone, just a lot it would seem. Does the designer jump to a low pin count micro, or do it with a 555. Do they stick to the hard 10mA provided to the led, or interpret the spirit of it and make a circuit to limit current, but keep the apparent brightness above 50%. Does the designer choose discreet components, or do most prefer a monolithic solution. Or, in what would seem to happen here, pick all the nits in a request for design until you're nitted right out of the contract.
The customer wants a blue led to indicate and powered by a battery cell. Design the circuit the customer wants.

 

The customer wants a blue led to indicate and powered by a battery cell. Design the circuit the customer wants.

. . .and tell him the cost implications, and tell him that a red LED would cost considerably less, and let him choose.

 

The goals are intended to bring out the structural choices people make in building practical circuits. The stated constraints (versions) are to create a context that forces those choices along certain lines but not according to method of doing it.



I think you missed:



Whichever direction the designer chooses is completely permissible. The explicit constraints include the given BoM, the circuit's function, and the versions of each circuit (e.g.: minimum parts count).

It is precisely how people choose to approach it that is of interest. The circuits have no hidden problems to solve, and clever hacks are not required. Instead, it's intended to see how people on AAC choose to build thing.

All of this said, it appears to be an abject failure. Useless save for the lesson that it didn't work as hoped (which is worth something).

Hi,

Oh ok thanks.

So then would it be acceptable to throw a (probably 8 pin) microcontroller at these designs?

If there is a need to boost the voltage, that can be done with the uC and a few other small passive parts, and of course the reason I chose this solution is because it is cheap and very, very flexible in how the LED (or LEDs) can be controlled, even by an optional external control. An interesting example might be to make a "flickering candle" with one or more LEDs using a short section of code for a pseudo random number generator.
To take it a little further, one or more of the input pins could be used to select the LED activity from a group of pre-programmed solutions.

Interesting side line here is not that long ago I was trouble shooting a fuel pump relay that had been manufactured in or around 1998, maybe earlier, and it had a lot of components on it. 99 percent of them could be replaced with one 8 pin microcontroller, even the cheapest $1 USD microcontroller part.

I was hooked on these things a long time ago. Before they became popular, I designed my own PCB microcontroller. It was of course not as simple as the ones we have today though taking up an entire PC board.

 

Hi,

Oh ok thanks.

So then would it be acceptable to throw a (probably 8 pin) microcontroller at these designs?

If there is a need to boost the voltage, that can be done with the uC and a few other small passive parts, and of course the reason I chose this solution is because it is cheap and very, very flexible in how the LED (or LEDs) can be controlled, even by an optional external control. An interesting example might be to make a "flickering candle" with one or more LEDs using a short section of code for a pseudo random number generator.
To take it a little further, one or more of the input pins could be used to select the LED activity from a group of pre-programmed solutions.

Interesting side line here is not that long ago I was trouble shooting a fuel pump relay that had been manufactured in or around 1998, maybe earlier, and it had a lot of components on it. 99 percent of them could be replaced with one 8 pin microcontroller, even the cheapest $1 USD microcontroller part.

I was hooked on these things a long time ago. Before they became popular, I designed my own PCB microcontroller. It was of course not as simple as the ones we have today though taking up an entire PC board.

In fact, for at least most of the variationa *I* would expect an 8-pin MCU, but they could also be done with discrete logic, 555s, and even purely analog circuits. I want to get an idea which direction people choose to go in.

 

You could have done that with a simple poll.

 

You could have done that with a simple poll.

Not really. There is a lot more information in circuit design, and a poll needs to have constrained answers.

Anyway, it was a failed effort and I can at least learn from that.

 

The goals are intended to bring out the structural choices people make in building practical circuits. The stated constraints (versions) are to create a context that forces those choices along certain lines but not according to method of doing it.

As a general rule. Ease of design into existing designs are my primary circuit design choices today.
For this project I needed 5vdc for an encoder on a 3.3 volt 32-bit controller board.
https://forum.allaboutcircuits.com/...tter-for-this-application.193257/post-1823831

This was the choice for that voltage.It's from a quality parts OEM that I trust from years of experience using their parts.
https://www.murata.com/products/productdata/8809985572894/MYRBP-B-W.pdf?1604930424000
https://www.mouser.com/ProductDetai...YRBP500080B21RE?qs=hd1VzrDQEGi2HKFlO8%2BP9Q==

 

Not really. There is a lot more information in circuit design, and a poll needs to have constrained answers.

Anyway, it was a failed effort and I can at least learn from that.

Ok, perhaps a questionnaire instead of a poll.

I don't know how much information you were expecting to glean from a single example, I doubt if a one-off project can really be a good indicator of a person's "design philosophy".

I might choose one method on Monday and a different method on Friday.

 

What are the part numbers of the baseline parts?
Descreat parts only or can we use IC's?

 

What are the part numbers of the baseline parts?
Descreat parts only or can we use IC's?

There are datasheets in the TS post, and the LED alternative is in this one.

There are no hidden constraints, as is stated in the first post and clarified in the thread. Other than the BoM comprises the given parts, you are free to use any additional components or approach you want based on how you would choose to solve the problems presented.

I'll add that you can include any parts that aren't required to make your circuit operate for your own practical reason (e.g.: adding a switch to turn the circuit off, if you decide to try to physically build it, is no problem at all and does no harm to the intent of the exercise which is focusing on which of several directions you choose to reach the goal.

Thanks for considering participating. If you do, I hope you have some fun with it, and maybe learn something.

 

Not a single "design" yet?
Arghhh.

 

Not a single "design" yet?
Arghhh.

It's a blinker, something that IMO is seldom designed in isolation from a serious main project past the total beginner/teaching stage. With even a simple 8-bit controller, the additional inclusion of a blinker is usually trivial, one led, one resistor and a few bytes of code.

 

Perhaps the TS would consider laying out an example demonstrating their own design process, just to get things rolling?