Circuit Design for Sensor Node
make me a circuit diagram about this.
0:05
Thought for a moment
I’ll create a concise circuit diagram for the existing water-level motor controller by reading the schematic, identifying the main functional blocks and nets, then saving a clean diagram in a project file.
1:34
Thought for 2 sec
Read schematic.
Thought for 2 sec
1/3 Read detailed schematic connectivity for the controller blocks
Thought for 4 sec
Read schematic.
Thought for 3 sec
2/3 Create or update a project file with a circuit diagram
Thought for 23 sec
Thought for 3 sec
3/3 Summarize the created diagram to the user
Thought for 2 sec
3/3 tasks completed.
Thought for a moment
I created a circuit diagram and short functional explanation for the water-level motor controller in Circuit Diagram - Water Level Motor Controller.
It shows the 5 V supply, LM31 sensor input, LM324 buffer/comparator/current-control stages, BD139 motor drive, full-tank LED, flyback diode, and key nets.
Add to schematic
Run ERC check
Find suitable parts
Add connectors
Explain sensor connection
do not do a block circuit, rather a schematic one, where the wires are connected, etc (should be redable for an laic)
Do the circuit i described
Refine this doc
Ask about this doc
Schematic Circuit - Water Level Motor Controller
This is a beginner-readable schematic-style wiring diagram for the water level motor controller. It is not a PCB layout drawing. It shows which pins and parts are electrically connected together.
Main schematic wiring diagram
Text
+5 V ANALOG SUPPLY from J1 pin 1 | | VCC5 +-----------------------+-----------------------+-------------------+ | | | | C3 C2 J3 pin 1 R5 10 uF 100 nF LM31 +5 V 10 k | | | | GND GND sensor +---- VFULL_REF ---- U1D pin 12 4IN+ | R6 10 k | GND J1 external 5 V input: J1 pin 1 = VCC5 J1 pin 2 = GND J3 LM31 water level sensor connector: J3 pin 1 = VCC5 J3 pin 2 = GND J3 pin 3 = LM31_OUT Sensor signal filter and buffer: J3 pin 3 ---- LM31_OUT ---- R1 1 k ---- SENSOR_FILT ---- U1A pin 3 1IN+ | C1 100 nF | GND U1A is used as a voltage follower: U1A pin 1 1OUT ---- VS_BUF ---- U1A pin 2 1IN- Current command generator: VS_BUF ---- R8 100 k ---- VCTRL_RAW ---- R10 68 k ---- GND | +---- U1B pin 5 2IN+ U1B is used as a voltage follower: U1B pin 7 2OUT ---- VCTRL ---- U1B pin 6 2IN- | +---- R9 24 k ---- VCTRL_RAW | +---- U1C pin 10 3IN+ Full tank shutoff and green LED: VCC5 ---- R7 560 ohm ---- LED1 anode LED1 cathode ---- FULL_SHUTOFF ---- U1D pin 14 4OUT | +---- D2 cathode U1D full-level comparator: U1D pin 12 4IN+ = VFULL_REF, about 2.5 V U1D pin 13 4IN- = VS_BUF U1D pin 14 4OUT = FULL_SHUTOFF Shutoff clamp: D2 cathode = FULL_SHUTOFF D2 anode = Q1_BASE Motor supply and motor connector: J2 external motor supply input: J2 pin 1 = VMOTOR J2 pin 2 = GND VMOTOR ----+---------------- J4 pin 1, motor positive | C4 100 uF | GND VMOTOR ---- C5 100 nF ---- MOTOR_LOW Flyback diode across motor path: D1 cathode = VMOTOR D1 anode = MOTOR_LOW J4 motor connector: J4 pin 1 = VMOTOR J4 pin 2 = MOTOR_LOW BD139 motor driver and current sense: J4 pin 2 ---- MOTOR_LOW ---- Q1 collector Q1 emitter ---- MOTOR_SENSE ---- R2 5 ohm 1 W ---- GND | +---- U1C pin 9 3IN- U1C current-control amplifier: U1C pin 10 3IN+ = VCTRL U1C pin 9 3IN- = MOTOR_SENSE U1C pin 8 3OUT = DRIVE_OUT U1C pin 8 3OUT ---- DRIVE_OUT ---- R3 220 ohm ---- Q1_BASE ---- Q1 base | R4 10 k | GND D2 also connects to Q1_BASE: D2 anode = Q1_BASE D2 cathode = FULL_SHUTOFF LM324 power pins: U1 pin 4 VCC = VCC5 U1 pin 11 GND = GND
Same circuit as a net-by-net connection list
Use this section like a wiring checklist. Every item on the same line is connected together.
Table
| Net name | Connected pins and parts |
|---|---|
| VCC5 | J1 pin 1, J3 pin 1, U1 pin 4 VCC, C2 pin 1, C3 pin 1, R5 pin 1, R7 pin 1 |
| GND | J1 pin 2, J2 pin 2, J3 pin 2, U1 pin 11 GND, C1 pin 2, C2 pin 2, C3 pin 2, C4 pin 2, R2 pin 2, R4 pin 2, R6 pin 2, R10 pin 2 |
| LM31_OUT | J3 pin 3, R1 pin 1 |
| SENSOR_FILT | R1 pin 2, C1 pin 1, U1 pin 3 1IN+ |
| VS_BUF | U1 pin 1 1OUT, U1 pin 2 1IN-, U1 pin 13 4IN-, R8 pin 1 |
| VFULL_REF | R5 pin 2, R6 pin 1, U1 pin 12 4IN+ |
| VCTRL_RAW | R8 pin 2, R9 pin 1, R10 pin 1, U1 pin 5 2IN+ |
| VCTRL | U1 pin 7 2OUT, U1 pin 6 2IN-, R9 pin 2, U1 pin 10 3IN+ |
| DRIVE_OUT | U1 pin 8 3OUT, R3 pin 1 |
| Q1_BASE | R3 pin 2, R4 pin 1, D2 anode, Q1 base |
| FULL_SHUTOFF | U1 pin 14 4OUT, LED1 cathode, D2 cathode |
| VMOTOR | J2 pin 1, J4 pin 1, C4 pin 1, C5 pin 1, D1 cathode |
| MOTOR_LOW | J4 pin 2, C5 pin 2, D1 anode, Q1 collector |
| MOTOR_SENSE | Q1 emitter, R2 pin 1, U1 pin 9 3IN- |
| LED resistor node | R7 pin 2, LED1 anode |
How to read it in simple words
- J1 provides the 5 V control supply for the LM324 and the LM31 sensor.
- J3 receives the LM31 water level sensor output.
- R1 and C1 clean the sensor signal before it enters the LM324.
- U1A buffers the sensor signal so the rest of the circuit does not disturb it.
- R8, R9, R10, and U1B make a motor-current command from the water-level signal.
- U1C compares that command with the voltage across R2, which represents motor current.
- U1C drives Q1 through R3. Q1 controls the motor current on the low side.
- U1D compares the water level to the full-tank reference from R5 and R6.
- When the tank is full, U1D lights LED1 and D2 pulls down Q1 base drive, stopping the motor.
- D1 protects Q1 from motor inductive kick, while C4 and C5 reduce motor supply noise.
Parts used
| Reference | Value or part | Purpose |
|---|---|---|
| U1 | LM324ADR | Quad op-amp for buffer, command buffer, current servo, and full comparator |
| Q1 | BD13916STU | Low-side motor current pass transistor |
| D1 | 1N4007RLG | Motor flyback diode |
| D2 | JAN1N4148UR-1 | Full-tank shutoff clamp diode |
| LED1 | SML-LX0805GC-TR | Green full-tank LED |
| R1 | 1 k | Sensor signal series filter resistor |
| R2 | 5 ohm, 1 W | Motor current sense resistor |
| R3 | 220 ohm | Q1 base current limiting resistor |
| R4 | 10 k | Q1 base pulldown resistor |
| R5 | 10 k | Upper resistor of 2.5 V full reference divider |
| R6 | 10 k | Lower resistor of 2.5 V full reference divider |
| R7 | 560 ohm | LED current limiting resistor |
| R8 | 100 k | Current command scaling resistor |
| R9 | 24 k | Current command feedback/scaling resistor |
| R10 | 68 k | Current command bias resistor |
| C1 | 100 nF | Sensor signal filter capacitor |
| C2 | 100 nF | LM324 supply decoupling capacitor |
| C3 | 10 uF | 5 V rail bulk capacitor |
| C4 | 100 uF | Motor supply bulk capacitor |
| C5 | 100 nF | Motor noise suppression capacitor |
| J1 | 2-pin terminal | 5 V control supply input |
| J2 | 2-pin terminal | Motor supply input |
| J3 | 3-pin terminal | LM31 sensor connector |
| J4 | 2-pin terminal | Motor connector |
Welcome 👋
Flux helps you build PCBs faster with an AI teammate!
Create your account to collaborate, stay updated, fork your own version, and get instant answers from our AI agent.