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Basic programm to use hidapi and report temp/co2 from Holtek Semiconductor, Inc. USB-zyTemp (hidapi is python3-hidapi in debian buster)
from hidapi import Device
vid = 0x04d9
pid = 0xa052
try:
print("Opening the device")
h = Device(vendor_id=vid, product_id=pid, blocking=False)
#h.open(vid, pid) # TREZOR VendorID/ProductID
print("Manufacturer: %s" % h.get_manufacturer_string())
print("Product: %s" % h.get_product_string())
print("Serial No: %s" % h.get_serial_number_string())
#print("Get feature report:")
#print(h.get_feature_report(bytes(1),2))
print("Send feature report:")
h.send_feature_report(bytearray([0xc4, 0xc6, 0xc0, 0x92, 0x40, 0x23, 0xdc, 0x96]), report_id=bytes(1))
try:
while True:
r = h.read(8)
if r:
# print('read: "{}"'.format(r))
metric = r[0]
value = r[1]
value_thousands = r[2]
checksum = r[3]
r4 = r[4]
if r4 != 0x0d:
continue
print("Unexpected data from device")
value_sum = metric + value + value_thousands
#if checksum != metric + value + value_thousands:
# continue
# print("Checksum error")
metric_name = ""
value_shifted = value << 8
metric_value = value_shifted + value_thousands
if metric == 0x42:
metric_name = "Temperature"
metric_value = metric_value / 16 - 273.15
elif metric == 0x50:
metric_name = "CO2"
elif metric == 0x44:
metric_name = "Humidity"
else:
continue
metric_name = "Unknown"
print(hex(metric), metric_name, "%.1f" % metric_value)
finally:
print("Closing the device")
h.close()
h.close()
except IOError as ex:
print(ex)
print("You probably don't have the hard-coded device.")
print("Update the h.open() line in this script with the one")
print("from the enumeration list output above and try again.")
print("Done")
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