Feedback for a circuit

Thread Starter

Mr_T_80

Joined Dec 11, 2021
5
Hi all,
I am very new to designing original circuits. After a while of research and a lot of learning I have designed my first circuit.
My goal for this circuit is to make two motors move an arm. I have attached a schematic. As I said I have very new to this and any constructive feedback would be greatly apricated.
Thank you.EG 1119.png
 

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ericgibbs

Joined Jan 29, 2010
15,369
G Day T,
Welcome to AAC.
Quick look at your circuit, powering the 555 timer from Gate outputs is a bad idea.
Have you built any 555 timer projects.?
E


Update:
What is the Spec on the motors, Voltage/Current etc.?
 

ElectricSpidey

Joined Dec 2, 2017
2,144
I also see some floating gates. (need to be tied to ground with a resistor)

Why do you have a resistor in one 555 VCC line and not the other?

If D2 & D3 are very low power and the 555 is CMOS, you "might" get away with driving them from a gate output...but I wouldn't recommend it. Directly power the 555s and use the reset line to turn them on and off.

Driving relays directly from gate outputs is generally a no-no as well.

R1 R2 R5 R6 are probably not needed.

What are R3 & R4 for?
 
Last edited:

MrChips

Joined Oct 2, 2009
25,931
You have your circuit design backwards.
Don't drive your logic gates before the voltage regulators.
Connect the voltage regulators to the supply first. Then do the logic following that.
You don't need mechanical relays. Solid-state switches would be better.

Before you start laying out the electrical design, set out on paper what are your requirements and specifications.

1) What are the inputs?
2) What are the outputs?
3) What are the input and output voltage and current requirements?
4) What are the timing requirements?
5) What is the circuit supposed to do under what conditions?

You may already have these things in your head. But we cannot read your mind.
 

Thread Starter

Mr_T_80

Joined Dec 11, 2021
5
G Day T,
Welcome to AAC.
Quick look at your circuit, powering the 555 timer from Gate outputs is a bad idea.
Have you built any 555 timer projects.?
E


Update:
What is the Spec on the motors, Voltage/Current etc.?
Hi E,
I have built 555 timer projects but they didn't have any gates. The motors are 3.3v and 0.28A with no load.
Thanks for the feedback,
T
 

Thread Starter

Mr_T_80

Joined Dec 11, 2021
5
You have your circuit design backwards.
Don't drive your logic gates before the voltage regulators.
Connect the voltage regulators to the supply first. Then do the logic following that.
You don't need mechanical relays. Solid-state switches would be better.

Before you start laying out the electrical design, set out on paper what are your requirements and specifications.

1) What are the inputs?
2) What are the outputs?
3) What are the input and output voltage and current requirements?
4) What are the timing requirements?
5) What is the circuit supposed to do under what conditions?

You may already have these things in your head. But we cannot read your mind.
Hi MrChips,
Thanks for your feedback. The main input is the switch labelled 'Action', all the other switches aren't inputs made by the user, they are to trigger actions based of the position of the arm. The output is a motor will move an arm. The motors run of 3.3v and run at 0.28A with no load, I have chosen to use a 9v power source with a voltage regulator to power the circuit. When the arm is is in one state, one of the LEDs will flash (at 1 second intervals) when in the other state the other LED will flash. When the state of the 'action' switch is changed by the user and the power is on, then it will trigger a relay to move an arm with two motors. It will also trigger a 555 timer as I have explained above. I hope this answers your question. Thanks for your feedback!
T
 

Thread Starter

Mr_T_80

Joined Dec 11, 2021
5
The schematic has many errors. but with no component values and no part numbers . . .

ak
Hi Analog Kid
The schematic I have provided is only a very rough plan, I am only posting it here as a 'proof of concept'. I will refine it at a later stage. This is why I haven't added component values or part numbers. If this is a mistake and I should add values in 'proof of concept' schematics please let me know. I am very new to this community.
T
 

AnalogKid

Joined Aug 1, 2013
9,973
I get that this is preliminary, but at least give us the IC part numbers. There are only about 99 very different things that can be symbolized as an AND gate.

Also, please explain your reasoning for R1, R2, R3, R4, R5, R6, and R7.

ak
 

iimagine

Joined Dec 20, 2010
501
Having 2 voltage regulators to drive 2 motors at which only one will be active at a time makes no sense. Same with having 2 555s driving 2 LEDs that only one will flash at a time.
 

Thread Starter

Mr_T_80

Joined Dec 11, 2021
5
Hi everyone,
Thanks for your help, I have learnt a lot and have made many changes to my schematic. As I have said I am very new to digital design and I am very grateful for your assistance. Thanks again.
T
 

ScottWang

Joined Aug 23, 2012
7,179
Please list the functions that you want as clearly as you can like MrChips did in #4, and then our members can modify or design a new circuit for you.
 

Reloadron

Joined Jan 15, 2015
6,544
U3 and U4 are driving relay coils. Will they have enough current capability to drive those relay coils? Not sure what C2 is all about but assume you want it wired like C3?

Ron
 

MrChips

Joined Oct 2, 2009
25,931
Scrap the electronics circuit design for the moment.

Start with the power source, the battery.
What is the voltage and capacity of the battery?
How long should the battery last before recharging is necessary?
To answer this you need to specify the voltage and current required by the rest of the circuit.
 
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