USB relay not working

I am using this USB relay:

SMAKN LCUS-1 type USB relay module USB intelligent control switch USB switch

To power a dosing pump:

Gikfun 12V DC Dosing Pump Peristaltic Dosing Head with Connector For Arduino Aquarium Lab Analytic Diy AE1207

This is the python code that gets it working and also has this .exe installed (SerialSend.exe; https://batchloaf.wordpress.com/serialsend/):

subprocess.check_output("serialsend.exe /baudrate 9600 /hex \\xA0\\x01\\x01\\xA2", shell=True)

time.sleep(10)

subprocess.check_output("serialsend.exe /baudrate 9600 /hex \\xA0\\x01\\x00\\xA1", shell=True)

Any tips in converting this to Matlab? I’ve tried this but nothing happens:

relayopen='\\xA0\\x01\\x01\\xA2';

relayclose='\\xA0\\x01\\x00\\xA1';

Ports=serialportlist;

JuicePort=Ports(3);

s=serial(JuicePort);

fopen(s)

fprintf(s,relayopen)

fclose(s)

Answer 1

[Walter Roberson]

relayopen = '\xA0\x01\x01\xA2';
relayclose = '\xA0\x01\x00\xA1';

Ports = serialportlist;
JuicePort = Ports(3);

s = serial(JuicePort, 'BaudRate', 9600);
fopen(s)

fprintf(s,relayopen)

fclose(s)

Note that serial() is going to go away, and you should change to serialport()

[Jessica Yorzinski]

Thanks for taking a look at this! Unfortunately, that doesn't quite work either. It runs without any errors but nothing happens with the pump. After the fopen(s), the port does change to being on (see below). Anything else you might suggest?

Serial Port Object : Serial-/dev/cu.usbserial-1410

Communication Settings

Port: /dev/cu.usbserial-1410

BaudRate: 9600

Terminator: 'LF'

Communication State

Status: open

RecordStatus: off

Read/Write State

TransferStatus: idle

BytesAvailable: 0

ValuesReceived: 0

ValuesSent: 18

[Walter Roberson]

relayopen = 0xA00101A2;
relayclose = 0xA00100A1;

Ports = serialportlist;
JuicePort = Ports(3);
s = serial(JuicePort, 'BaudRate', 9600, 'ByteOrder', 'bigendian');
fopen(s);

fwrite(s, relayopen);
sleep(5);
fwrite(s, relayclose);

fclose(s)

[Jessica Yorzinski]

Thanks for giving me something else to try! Unfortunately, it is still the case that the pump isn't triggered (even though that Python code running on the same machine does trigger it). There are no errors-- just nothing happens. Any other things I could try?