farm.lua

local channel = 1
local modem = peripheral.wrap("top")
local rsSide = "left"

function send(message)
    print("Sending message '" .. message .. "'")
    modem.transmit(channel, channel, message)
end

print("Computer listening for redstone from the " .. rsSide)

while true do
    os.pullEvent("redstone")
    while (rs.getOutput("right")) do
        sleep(4)
    end
    if rs.getAnalogInput(rsSide) == 15 then
        send("finish")
        return
    elseif rs.getAnalogInput(rsSide) > 0 then
        if rs.getInput("front") then
            send("remove")
        else
            send("replace")
        end
    end
end