Question about servo motor control with 555 timer by external signal

Thread Starter

ryumangdung

Joined Oct 21, 2023
12
Hello. It's my first time doing electronic work, so I'm not good enough.
That's why I came all the way here. I'd really appreciate it if you could let me know.

I want to implement a system that detects water rising in the tunnel during heavy rains and controls the entrance with barricade using servo motor.

I'm trying to control the servo motor 90 degrees at a certain level using a water level sensor without MPU, and I want to know how to connect the output of lm339 to the 555 timer.
lm339_gate.png
As shown in the circuit diagram, I have set the thresholds for the firtst and secondary water levels. And I implemented it so that the led turns on according to the height.
.

First of all, the circuit that controls the motor with the button has been successful, but I need advice on how to remove the button and connect it.
서보모터버튼.png

I want to implement the barricade by controlling the servo motor 90 degrees when the water reaches the second water level with LED and controlling it 90 degrees again when it goes down to the first water level
How should I connect it?
 

Alec_t

Joined Sep 17, 2013
14,214
At a quick glance it seems you could remove U3 and U4 and replace each of SW1 and SW2 with a respective PNP transistor having its base connected to the relevant LED anode. But some latching or timing arrangement seems necessary with the comparison circuitry to allow the servo to move fully from one extreme position to the other.
 

Thread Starter

ryumangdung

Joined Oct 21, 2023
12
At a quick glance it seems you could remove U3 and U4 and replace each of SW1 and SW2 with a respective PNP transistor having its base connected to the relevant LED anode. But some latching or timing arrangement seems necessary with the comparison circuitry to allow the servo to move fully from one extreme position to the other.
Thank you for replying!
Should I remove the logic gate and write the transistor?
I want to operate selectively according to the two input signals, but does the transistor function the same?
I don't understand well because I don't know well..
 

Alec_t

Joined Sep 17, 2013
14,214
I want to implement a system that detects water rising in the tunnel during heavy rains and controls the entrance with barricade using servo motor.
How big is this tunnel? A servo intended for RC models won't have much torque and its control is quite different from that of a large industrial servo.
 

Thread Starter

ryumangdung

Joined Oct 21, 2023
12
How big is this tunnel? A servo intended for RC models won't have much torque and its control is quite different from that of a large industrial servo.
it is a just small project in person , so I'm planning to model it according to the size of the servo motor!
 
Last edited:

sghioto

Joined Dec 31, 2017
5,369
Here's my take on how it can be configured with the LM339 and a 555.
When first powered up and both level indicators are OFF, Q3 will conduct releasing the reset pin5 and allowing the 555 to send the signal to the servo timed out by LM339 "C".
When level 1 is reached Q1 activates and shuts OFF Q3.
When level 2 is reached Q2 conducts releasing the reset pin5 and allowing the 555 to send the second frequency to the servo timed out by LM339 "D"
When the water drops below level 1 Q1 and Q2 are both OFF allowing Q3 to conduct activating the servo as explained before.
1699234988796.png
 

Thread Starter

ryumangdung

Joined Oct 21, 2023
12
Here's my take on how it can be configured with the LM339 and a 555.
When first powered up and both level indicators are OFF, Q3 will conduct releasing the reset pin5 and allowing the 555 to send the signal to the servo timed out by LM339 "C".
When level 1 is reached Q1 activates and shuts OFF Q3.
When level 2 is reached Q2 conducts releasing the reset pin5 and allowing the 555 to send the second frequency to the servo timed out by LM339 "D"
When the water drops below level 1 Q1 and Q2 are both OFF allowing Q3 to conduct activating the servo as explained before.
View attachment 306861
wow! thank you so much!!
(^▽^)/ ʸᵉᔆᵎ
 
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