What is causing my Nodemcu/ESP 8266 to reset? - lua

Question

I am using a sensor similar to hall effect sensor to count the number of interrupts. After some random time, usually after it has been ON for 1-2 hours it resets and followed by random resets at random intervals.
counter = 0;
sampletime = 0;
lastrisetime = tmr.now()
pin = 2
do
gpio.mode(pin, gpio.INT)
local function rising(level)
-- to eliminate multiple counts during a short period (.5 second) difference is taken
if ((tmr.now() - lastrisetime) > 500000) then
lastrisetime = tmr.now();
end
-- when tmr.now() resets to zero this takes into account that particular count
if ((tmr.now() - lastrisetime) < 0) then
lastrisetime = tmr.now();
end
end
local function falling(level)
if ((tmr.now() - lastrisetime) > 500000) then
-- Only counted when the pin is on falling
-- It is like a sine curve so either the peak or trough is counted
counter = counter + 1;
print(counter)
lastrisetime = tmr.now();
sampletime = lastrisetime;
end
-- when tmr.now() resets to zero this takes into account that particular count
if ((tmr.now() - lastrisetime) < 0) then
lastrisetime = tmr.now();
counter = counter + 1;
print(counter)
end
end
gpio.trig(pin, "up", rising)
gpio.trig(pin, "down", falling)
end
This is the error I get on CoolTerm, also I checked for memory every couple of hours and you can see the results there.
NodeMCU 0.9.6 build 20150704 powered by Lua 5.1.4
> Connecting...
connected
print(node.heap())
22920
> print(node.heap())
22904
> print(node.heap())
22944
> print(node.heap())
22944
> 2. .print(node.heap())
22944
> print(node.heap())
22944
> ∆.)ç˛.䂸 ã ¸#H7.àåË‘
NodeMCU 0.9.6 build 20150704 powered by Lua 5.1.4
> Connecting...
connected
print(node.heap())
21216
> F.)ç˛.¶Ùå¶1.#H  .ÊÍ
NodeMCU 0.9.6 build 20150704 powered by Lua 5.1.4
> Connecting...
connected
H!໩.ä‚D.ã ¸å¶H.åb‘
NodeMCU 0.9.6 build 20150704 powered by Lua 5.1.4
> Connecting...
connected
print(node.heap())
22904
> print(node.heap())
21216
>
Thank you for taking the time to read this. Appreciate your input.

Answer 1

Possible watchdog timer issue.
In your interrupt service routine looks like you are waiting too much.
Better to remove timing operations from there, just set a flag and in another loop, check the flag status and complete your timing operations.

Answer 2

NodeMCU 0.9.6 build 20150704 powered by Lua 5.1.4
The first thing really is to use a recent version of the NodeMCU firmware. 0.9.x is ancient, contains lots of bugs and is no longer supported. See here https://github.com/nodemcu/nodemcu-firmware/#releases
lastrisetime = tmr.now()
The real issue is that tmr.now() rolls over at 2147 seconds I believe. I learned about this when I worked on a proper debounce function.
-- inspired by https://github.com/hackhitchin/esp8266-co-uk/blob/master/tutorials/introduction-to-gpio-api.md
-- and http://www.esp8266.com/viewtopic.php?f=24&t=4833&start=5#p29127
local pin = 4 --> GPIO2
function debounce (func)
local last = 0
local delay = 50000 -- 50ms * 1000 as tmr.now() has μs resolution
return function (...)
local now = tmr.now()
local delta = now - last
if delta < 0 then delta = delta + 2147483647 end; -- proposed because of delta rolling over, https://github.com/hackhitchin/esp8266-co-uk/issues/2
if delta < delay then return end;
last = now
return func(...)
end
end
function onChange ()
print('The pin value has changed to '..gpio.read(pin))
end
gpio.mode(pin, gpio.INT, gpio.PULLUP) -- see https://github.com/hackhitchin/esp8266-co-uk/pull/1
gpio.trig(pin, 'both', debounce(onChange))