Reference
Output Format
| Num | Pin | Description |
|---|---|---|
| 1 | VCC | 5V~12V Power input |
| 2 | RX | Receive serial data under RS232 mode |
| 3 | TX | Output serial data under RS232 mode |
| 4 | Vout | Output Voltage under voltage analog mode |
| 5 | GND | Ground |
RS232 Output
If currently it is not in the RS232 output mode, you can switch to this mode by short-pressing. when successfully switched, the LED flashes blue three times, stop 1 second and flashes three times again.
Every time the controller is powered on, it will automatically start detecting with 500ms working period, and "3.TX" will output one frame serial data.
If the input pin "2.RX" receives the correct serial command, the controller will output data under the control of the command. When receiving commands once, the controller will be triggerred once and output one frame serial data. But the trigger period must be over 60ms.
To distinguish between different controllers, users can change the addresses of different controllers through the corresponding instruction code. It won't be lost when powered down.
Command frame format of serial communication
| Interface Type | Start byte | Data byte | Stop byte | Parity check | Band rate |
|---|---|---|---|---|---|
| Full duplex | 1 | 8 | 1 | None | 9600 |
Output frame format
| Frame Header ID | Controller Address(0x01 default) | Distance Data High | Distance Data Low | Temperature Data High | Temperature Data Low | Checksum |
|---|---|---|---|---|---|---|
| 0xFF | Add | Data_H | Data_L | Temp_H | Temp_L | SUM |
Distance Calculation
Distance=Data_H*256+Data_L
Temperature Calculation
When the highest bit of Temp_H is 0, the temperature value is positive; when it is 1, the temperature value is negative.
If Temp_H=0x01=0b0000 0001, the most highest bit is 0, which means the temperature value is positive.
Temperature=Temp _H*256+ Temp _L
Checksum Calculation
Just reserve the eight lower bits of the accumulated value of checksum.
SUM=(frame header+ Data_H+ Data_L+ Temp_H+ Temp_L)&0x00FF
Example for Auto-output
T1=T2=T3=500ms
Example for Controlled Output
T1=1~55ms
Example 1
Read the distance and temperature of the controller whose address is 0x01.
| Frame Header | Add | Control Command | SUM | |
|---|---|---|---|---|
| Host sends | 0xFF | 0x01 | 0x01 | 0x01 |
| Frame Header ID | Controller Address(0x01 default) | Distance Data High | Distance Data Low | Temperature Data High | Temperature Data Low | Checksum | |
|---|---|---|---|---|---|---|---|
| Slave sends back | 0xFF | Add | Data_H | Data_L | Temp_H | Temp_L | SUM |
Example 2
Change the controller address to 0x05
| Frame Header | Add | Control Command | SUM | |
|---|---|---|---|---|
| Host sends | 0xFF | 0x05 | 0x03 | 0x07 |
| Frame Header | Add | Control Command | SUM | |
|---|---|---|---|---|
| Slave sends back | 0xFF | 0x05 | 0x03 | 0x07 |
After the above instruction done, the controller address will be changed into: Add=0x05. The control command is 0x03, which is used to change address.
Principle
The sensor, like many other ultrasonic sensors, based on the principle of ultrasonic echo ranging, determines the distance to a target by measuring time lapses between the sending of a pulse and receiving of the echo without contacting.
Voltage Analog Output
Switch to Voltage analog output mode
Switch to the voltage analog output mode by short-pressing. When successfully switched, the LED flashes blue once, stop 1 second, and flashed once again.
The controller will automatically detect distance with 500ms period and output voltage in proportion to the detected distance.
Voltage vs Distance
Calculation
Under voltage analog output mode, read the output voltage from the pin "4.Vout", then we can calculate the related distance. The controller's voltage from 0.0V to 3.30V corresponds with the distance from 0-330cm, which also means 0.01V is equal to 1cm. When the detected distance is larger than 330cm or no object is detected, it outputs 3.30V voltage.
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