Document this 555 / 4017 on/off circuit

ThomsCircuit · Apr 26, 2020

eTech said:
The current design produces a single pulse if the button is held down. If your touch switch produces a pulse, the pulse would need to be longer than the pulse incorporated in the design. Can you confirm how your touch plate output works in both latch and pulse modes?

eT

I can offer this file. I can configure it any way necessary.

Some of my switches are on snap action roller type like shown. I have NOT ordered these yet. But this switch triggers a light for a door that is opened and closed. If you know of a switch that I could use in its place that works with your circuit that would be great.

I apologize if I'm being difficult. I will do everything possible to make this work.

ThomsCircuit · Apr 26, 2020

eTech said:
This design works the same as before except I replaced all the mosfets with a single TBD62003A "MOSFET Array" chip.

This is what I found. Can you verify from this image that this is correct?

eTech · Apr 26, 2020

ThomsCircuit said:
I can offer this file. I can configure it any way necessary.

Some of my switches are on snap action roller type like shown. I have NOT ordered these yet. But this switch triggers a light for a door that is opened and closed. If you know of a switch that I could use in its place that works with your circuit that would be great.

I reviewed your images.

PCB appears to have two settings.
If i understand correctly, you will need to set:
1. Active high.
Output is 0v and changes to 5v when the input is activated.

2. Momentary
Output is active as long as input is active

But rather than me trying to choose your switch, the design's input spec:
1. Input voltage is same as supply voltage.
2. Input triggers on rising edge of input signal.

So...
If the touch switch output remains high as long as a finger has it pressed....that will work.
If the touch switch output remain high only for a moment...that will also work...as long as it remains high for a few milliseconds.

I apologize if I'm being difficult. I will do everything possible to make this work.

No worries.

eTech · Apr 26, 2020

ThomsCircuit said:
This is what I found. Can you verify from this image that this is correct?

Yes. That looks correct.

ThomsCircuit · Apr 26, 2020

Ok fabulous! I mean it too. This thingy works with a pulse or a latch. I'm speechless. It's got a lot of chips and resistors but it works and just wow!

ThomsCircuit · Apr 27, 2020

Looking at your new drawing. Noticed that you have the relay labeled at 30ma. It just might be a mistake in labeling as the 30ma is the buzzers current. The relay is 70ma

eTech · Apr 27, 2020

ThomsCircuit said:
Looking at your new drawing. Noticed that you have the relay labeled at 30ma. It just might be a mistake in labeling as the 30ma is the buzzers current. The relay is 70ma

Hi

No worries...there is plenty of drive capacity.
I changed the current draw of the relay. No change in design.
I've updated the drawing.

ThomsCircuit · Apr 27, 2020

I do not see this as an issue but my led is a dual color with a common cathode. Would I just connect the anode of each lead to pins 12 & 14 of the 62003? I could also share the resistor on the cathode if that's ok.

eTech · Apr 27, 2020

ThomsCircuit said:
I do not see this as an issue but my led is a dual color with a common cathode. Would I just connect the anode of each lead to pins 12 & 14 of the 62003? I could also share the resistor on the cathode if that's ok.

The mosfets inside the array are NMOS transistors and short to ground when they turn on. So common cathode LED's won't work.
They have to be common anode or separate LEDs. They also should not share a resistor and each should have their own limiting resistor.

eT

ThomsCircuit · Apr 27, 2020

eTech said:
They have to be common anode or separate LEDs. They also should not share a resistor and each should have their own limiting resistor.

Not a problem. I'll order a dozen. Only $1.50

ThomsCircuit · Apr 30, 2020

I've put this circuit board layout together for two reasons. So you can see how it fits on the two 80x20mm circuit boards and that I comprehend your schematic. If I have any mistakes I'll edit the file. I added an led so I can see that the trigger has been pressed. I'd like to add one to also show that the relay has been triggered. But that's after I have got this documented well. Thanks in advance for taking a look.

eTech · Apr 30, 2020

ThomsCircuit said:
I've put this circuit board layout together for two reasons. So you can see how it fits on the two 80x20mm circuit boards and that I comprehend your schematic. If I have any mistakes I'll edit the file.

How long are the interconnecting wires?

I also recommend using a schematic capture and PCB layout program to create your board. It will greatly help keep the schematic and board layout "in sync" with each other. There are various good free programs available.

I added an led so I can see that the trigger has been pressed. I'd like to add one to also show that the relay has been triggered. But that's after I have got this documented well. Thanks in advance for taking a look.

As currently designed:
1. The Green led will be lit when the relay is energized.
2. The Red led will be lit when the system is "ready".
3. The Yellow led will be lit when the timer is running (New- I'll add this at the timer output).

Is this OK? Or did you want another led for the relay?
I think adding another led for the relay isn't really needed, but its up to you.

I would add a power indicator LED.

I also recommend the following colors (but again, its up to you):
Red - PWR ON
Yellow - TIMER ON
Green - READY
Blue - RLY ON

I'll update the schematic after your reply.

ThomsCircuit · Apr 30, 2020

If you could suggest a program (free)
All those led updates are great. I have all those colors too. LEDs are 2v .20ma
The two circuit boards are an inch from each other. One is atop the other seperated with 12mm stand offs. I do hope I got the layout right.
Thank you

eTech · Apr 30, 2020

ThomsCircuit said:
If you could suggest a program (free)

Look on this forum. There are many discussions and many opinions

All those led updates are great. I have all those colors too. LEDs are 2v .20ma

OK...You may have to adjust the values of the limiting resistor for each color to get the desired brightness.
BTW- I'll plan to use the last open channel of the mosfet array to drive the Timer LED.

The two circuit boards are an inch from each other. One is atop the other seperated with 12mm stand offs. I do hope I got the layout right.
Thank you

OK....then that will be fine.

If you need a project box, there are some good ones available at Hammond:

Small Enclosures

Length Width Height Units inchmm

www.hammfg.com

Be aware that you need to decide on an enclosure before laying out the PCB because the enclosure may affect the shape and size, and mounting hole locations on the PCB. Some even have molded standoffs for mounting a PCB.

I'll update the schematic shortly.

eTech · Apr 30, 2020

ThomsCircuit said:
All those led updates are great. I have all those colors too. LEDs are 2v .20ma

I just noticed this.
Is this a typo and should be 20mA or are they really 200uA each?

ThomsCircuit · Apr 30, 2020

18-20mA not 200uA

eTech · Apr 30, 2020

Updated schematic.

ThomsCircuit · Apr 30, 2020

Thank you for the update. The parts will take forever to arrive so if the thread goes quiet for awhile it's because of the shipping delay.

I did look at "design spark" for a pcb layout software.

About the project boxes. I have constructed a large 9x9x5 box. It holds the power supply, volt & amp meters, fuse protection, fan and power rails. There's plenty of room for 8 of these completed circuits. What's not in the box it the touch sensor. Its located near each light. You dont see it. You touch a metal plate that's attached by a 6-10" wire to the sensor. The trigger out of the sensor is sent to the circuits (SIG IN). That wire is anywhere from 5 to 12 feet away. I've tested all this on a breadboard and the voltage loss is less than 1 volt. That's why the SIG IN is 4volts.

eTech · Apr 30, 2020

ThomsCircuit said:
I did look at "design spark" for a pcb layout software.

I use DesignSpark PCB and have used it for a few years. It is excellent software.

Do you intend to make a thru hole PCB or surface mount PCB?

About the project boxes. I have constructed a large 9x9x5 box. It holds the power supply, volt & amp meters, fuse protection, fan and power rails. There's plenty of room for 8 of these completed circuits. What's not in the box it the touch sensor. Its located near each light. You dont see it. You touch a metal plate that's attached by a 6-10" wire to the sensor. The trigger out of the sensor is sent to the circuits (SIG IN). That wire is anywhere from 5 to 12 feet away. I've tested all this on a breadboard and the voltage loss is less than 1 volt. That's why the SIG IN is 4volts.

That's good to know.
The minimum voltage for CMOS logic high with a 5 volt supply is 3.5v. Hopefully that's OK. if not, we'll have to add a level shifter at the input to restore the input voltage level to 5v. That could be in the form of a transistor switch at the input.

ThomsCircuit · May 1, 2020

eTech said:
Do you intend to make a thru hole PCB or surface mount PCB?

Through hole. 20x80mm 2.54 pitch

eTech said:
if not, we'll have to add a level shifter at the input to restore the input voltage level to 5v. That could be in the form of a transistor switch at the input.

I could go ahead and order the necessary components. Lmk what they would be. I have bc547,bc548, and bc327

Document this 555 / 4017 on/off circuit

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