Import records from a DustTrak log

read_dusttrak.R

read_dusttrak <- function(
  file, 
  header_rows = 18
) {
  header <- read.csv(file, nrow = header_rows, header = FALSE, stringsAsFactors = FALSE)
  header <- as.list(setNames(header$V2, header$V1))
  records <- read.csv(file, skip = header_rows + 1, header = TRUE, stringsAsFactors = FALSE)
  names(records) <- c("elapsed", "value", "alarm", "error")
  start_mdYHMSp <- with(header, paste(`Test Start Date`, `Test Start Time`))
  records <- data.frame(start = mdy_hms(start_mdYHMSp) + records$elapsed, 
                        mutate(records, value = as.integer(value * 1000))) # as ug/m3
  attr(records, "header") <- header
  return(records)
}