@westh/umxxc-parser

Parse messages from UMxxC devices, that is for instance the UM24C, UM25C, or the UM34C.

This parser is a derivative of these guys' work:

• bzgex/UM34C_BT
• kolinger/rd-usb
• sebastianha/um34c

Whereas the above repos provide a complete 'suite' for getting and parsing the data from a UMxxC device this is merely the parser.

Installation

npm install @westh/umxxc-parser

Usage

const umxxcParser = require('@westh/umxxc-parser')

const messageToBeParsed = Buffer.from('...') // ...however you get your data from the UMxxC device
const parsedMessage = umxxcParser.parse(messageToBeParsed)

The parsedMessage will contain something that looks like the following:

{
  model: 'UM34C',
  voltage: 4.84, // [V] for UM25C this value will be decivolts
  current: 25, // [mA] for UM25C this value will be tenth-milliamps
  power: 121, // [mW]
  temperature: {
    celsius: 23,
    fahrenheit: 74
  },
  selectedGroup: 0,
  groups: [
    { accumulatedCurrent: 2, accumulatedPower: 10 }, // [mAh] [mWh]
    { accumulatedCurrent: 0, accumulatedPower: 0 },
    { accumulatedCurrent: 0, accumulatedPower: 0 },
    { accumulatedCurrent: 0, accumulatedPower: 0 },
    { accumulatedCurrent: 0, accumulatedPower: 0 },
    { accumulatedCurrent: 0, accumulatedPower: 0 },
    { accumulatedCurrent: 0, accumulatedPower: 0 },
    { accumulatedCurrent: 0, accumulatedPower: 0 },
    { accumulatedCurrent: 0, accumulatedPower: 0 },
    { accumulatedCurrent: 0, accumulatedPower: 0 }
  ],
  usbDataPlus: 0.04, // [V]
  usbDataMinus: 0.03, // [V]
  chargingMode: 7,
  accumulatedCurrent: 2, // [mAh]
  accumulatedPower: 10, // [mWh]
  thresholdCurrent: 0, // [A] and is the threshold at which accumulated... is captured
  accumulatedTime: 390, // [s]
  connected: 1,
  screenTimeout: 1,
  screenBrightness: 3,
  resistance: 193.6, // [Ω]
  screenMode: 2,
  unknown: <Buffer 15 d4>
}

Description

Basically the parser does what is described below to whatever Buffer you might throw at it. The calculations mentioned in the 'Meaning' column are taken care of, except for the edge cases for the UM25C which are not handled at the moment.

Offset	Length	Type	Meaning
0	2	model	Model ID
2	2	measurement	Voltage - UM25C: millivolts (divide by 1000 to get V), UM24C/UM34C: centivolts (divide by 100 to get V)
4	2	measurement	Amperage - UM25C tenth-milliamps (divide by 10000 to get A), UM24C/UM34C: milliamps (divide by 1000 to get A)
6	4	measurement	Wattage (in mW, divide by 1000 to get W)
10	2	measurement	Temperature (in Celsius)
12	2	measurement	Temperature (in Fahrenheit)
14	2	configuration	Currently selected data group, zero-indexed
16	80	measurement	Array of 10 main capacity data groups (where the first one, group 0, is the ephemeral one) -- for each data group: 4 bytes mAh, 4 bytes mWh
96	2	measurement	USB data line voltage (positive) in centivolts (divide by 100 to get V)
98	2	measurement	USB data line voltage (negative) in centivolts (divide by 100 to get V)
100	2	measurement	Charging mode index
102	4	measurement	mAh from threshold-based recording
106	4	measurement	mWh from threshold-based recording
110	2	configuration	Currently configured threshold for recording (in centiamps, divide by 100 to get A)
112	4	measurement	Duration of threshold recording, in cumulative seconds
116	2	configuration	Threshold recording active (1 if recording, 0 if not)
118	2	configuration	Current screen timeout setting, in minutes (0-9, 0 is no screen timeout)
120	2	configuration	Current backlight setting (0-5, 0 is dim, 5 is full brightness)
122	4	measurement	Resistance in deci-ohms (divide by 10 to get ohms)
126	2	configuration	Current screen (zero-indexed, same order as on device)
128	1	unknown
129	1	checksum/unknown	Checksum (UM34C) or unknown

Source RDTech UM series by sigrok.

Testing

Running yarn test will first run yarn build and then test both the CommonJS and ESM version.

License

GPL-3.0