Useful mostly for forcing sub-second timing in R

johnnyfive.R

library(RJSONIO)
library(ggplot2)
library(reshape2)
accel.list <- fromJSON(file.path("~/dev/bocoup", "johnny-five", "accel.json"))

accelToDF <- function(x) {
  sm <- x[["smooth"]]
  rough <- x[["accel"]]
  time <- x[["time"]]
  names(sm) <- c("X", "Y")
  names(rough) <- c("X", "Y")
  out.df <- data.frame(Type = c("smooth", "accel"),
                       rbind(sm, rough),
                       Time = time)
  return(out.df)
}
accel.df <- do.call(rbind, lapply(accel.list, accelToDF))
rownames(accel.df) <- as.character(1:nrow(accel.df))

timeNS <- function() {
  options(digits.secs = 6)
  timed <- unclass(as.POSIXlt(substring(accel.df[, "Time"], 12, 23),
                              "%H:%M:%OS", tz = "UTC"))
  timed <- ((timed$sec / 60 + timed$min) / 60 + timed$hour) * 3600
  timed <- timed - timed[1]
  options(digits.secs = 3)
  return(timed)
}

accel.df[, "Time"] <- timeNS()
accel.melt <- melt(accel.df[, names(accel.df) != "Time"])
accel.melt[, "Time"] <- accel.df[, "Time"]


ggplot(accel.melt) + geom_line(aes(x = Time, y = value, colour = Type)) +
  facet_grid(variable ~ .)