I have a KY-022 IR module that I can't get to work on my NodeMCU. I've been searching for some code samples in Lua on the internet with no luck. Can anyone point me in the right direction? Any code samples would be greatly appreciate it.
At the moment I have the following code:
local pin = 4
gpio.mode(pin, gpio.OPENDRAIN, gpio.PULLUP)
gpio.trig(pin, "down", function (level, micro)
print(gpio.read(pin), level, micro)
end)
When I press a button on the remote, I get something like this:
0 0 571940709
0 0 571954086
0 0 571955257
1 0 571958694
1 0 571963275
1 0 571969917
0 0 571974347
0 0 571980989
1 0 571983203
1 0 571987709
0 0 571993359
1 0 572000078
0 0 572004508
0 0 572047513
0 0 572058674
So, how do I get from that to figuring out which key was pressed on the remote?
After a month or so i've reopened this project and played around with it some more. As piglet suggested, I started listening for both high and low signals. The data is still very inconsistent and can't get a stable reading.
(And by the way, thanks for the vote-down piglet, that was greatly appreciated. I wish you could have seen my search history before you decided that i'm ignorant)
I'm going to post my curent code maybe somebody can point out what I'm doing wrong here.
local pin = 4
local prevstate = false
local prevmicro = 0
local prevtime = 0
local count = 0
gpio.mode(pin, gpio.INT)
gpio.trig(pin, "both", function (level, micro)
--local state = gpio.read(pin)
local state = level
if (micro - prevmicro) > 90000 then
prevmicro = 0
prevstate = false
count = 0
print("\n#", "st", "lv", "microtime", "timing")
end
if prevstate ~= state then
time = math.floor((micro - prevmicro)/100)
prevstate = state
prevmicro = micro
if time > 3 and time < 1000 then
if prevtime > 80 and prevtime < 100 then
if time > 17 and time < 25 then
print('Repeat')
elseif time > 40 and time < 50 then
print('Start')
end
else
print(count, gpio.read(pin), level, micro, time)
count = count + 1
end
prevtime = time
end
end
end)
and here are some sample readouts from pushing the same button:
# st lv microtime timing
1 1 1 1504559531 16
2 1 0 1504566995 74
3 0 1 1504567523 5
4 1 0 1504573619 60
5 0 1 1504587422 138
6 1 0 1504588011 5
7 1 1 1504604250 162
8 1 0 1504605908 16
9 1 1 1504659929 540
10 1 0 1504662154 22
# st lv microtime timing
1 1 1 1505483535 16
2 1 0 1505491003 74
3 0 1 1505491558 5
4 1 0 1505497627 60
5 0 1 1505511409 137
6 1 0 1505512023 6
7 1 1 1505518186 61
8 1 0 1505527733 95
9 1 0 1505586167 22
10 1 1 1505586720 5
# st lv microtime timing
1 1 1 1507990937 16
2 1 0 1507998405 74
3 0 1 1507998934 5
4 1 0 1508005029 60
5 0 1 1508018811 137
6 1 0 1508019424 6
7 1 1 1508035641 162
8 1 0 1508037322 16
9 1 1 1508091345 540
10 1 0 1508093570 22
As it turns out, the Lua code required for this is actually quite simple.
Where the code above is falling over is actually the print statements. These are extremely expensive and basically, kill your sampling resolution until it's useless.
You are in essence, writing an interrupt service routine, you have a limited time budget before you have to read the next edge change and if it happens before you are done processing, tough luck! So you need to make the ISR as efficient as you can.
In the example below, we listen to the "both" edge event, when one occurs, we simply record an indication of which edge and what duration.
Periodically (using a timer) we print out the contents of the waveform.
This perfectly matches the waveform on my logic analyzer, you still have the challenge of decoding the signal. Though, there are lots of great protocol docs that explain how to take accurate waveform data and use it to determine the signal being sent. I found that a lot of cheap "brand x" remotes appear to be using the NEC protocol, so this might be a good place to start depending on your project.
IR transmission because of its nature is not completely error-free so you may get a spurious edge signal from time to time but the code below is pretty stable and runs quite well in isolation, I have yet to test it when the Microcontroller is under more load than just listening for IR.
It may turn out that using Lua for this purpose is not the best due to the fact that it is an interpreted language (each command issued is parsed and then executed at runtime, this is not at all efficient.) But I will see how far I can get before I decide to write a c module.
local irpin = 2
local lastTimestamp = 0
local waveform = {}
local i = 1
gpio.mode(irpin,gpio.INT)
gpio.trig(irpin, "both", function(level, ts)
onEdge(level, ts)
end)
function onEdge(level, ts)
waveform[i] = level
waveform[i+1] = ts - lastTimestamp
lastTimestamp = ts
i = i+2
end
-- Print out the waveform
function showWaveform ()
if table.getn(waveform) > 65 then
for k,v in pairs(waveform) do
print(k,v)
end
i = 1;
waveform = {}
end
end
tmr.alarm(0, 1000, 1, showWaveform)
print("Ready")