In this Instructable I will show you how to make your own version of a BBQ tool that measures the current temperature in your barbecue and turns on a fan to light it up if needed. Additional to this there is also a meat core temperature sensor attached, and this all is (in my case) connected to Domoticz: real time read out of current temperatures and also logging.
Supplies:
Things you need:
- Wemos D1 mini (1x)
- MAX31855 Thermocouple module including probe (2x)
- Potentiometer 10k Ohm (1x)
- LCD 2004 incl I2C module (1x)
- IRF 520 mosfet (1x)
- Fan 5v (2x)
- LM2596 DC supply (1x) – set output to 5v, input can vary
- Housing (1x)
- Connectors for thermocouple (2x) – (connect to both MAX31855’s with the probes)
- DC connector female (2x) – one for DC in (depending on DC power supply socket)
- DC connector male (1x) – for connecting the fans
- Nut and bolt M3 x 30
- DC powersupply at least 5v
- some twin-wire – for connecting the fans.
- old USB mini cable – for powering the D1 mini
Tools you need:
- Soldering station
- Drills in several sizes
- Cutting tool for display
Step 1: Preparing Your Housing
At first, measure the size of the display. Make a cutting in the top of the housing to the display fits in nicely. Then make two holes at the location of the mouting holes in the backplate of the LCD (see photo).
Than use the bolts M3x30 to mount the display in the housing, see other picture from the top.
Now we start connecting / soldering all the parts together.
Step 2: Soldering
Now it’s time to connect all the parts together, see picture and below:
Wemos D1 mini -> MAX31855 (BBQ)
3v3 -> VCC
GND -> GND
D6/ GPIO12 -> SO
D5 / GPIO14 -> SCK
D8 /GPIO15 -> CS
Wemos D1 mini -> MAX31855 (meat)
3v3 -> VCC
GND -> GND
D6/ GPIO12 -> SO
D5 / GPIO14 -> SCK
D4 /GPIO2 -> CS
Wemos D1 mini -> Potmeter
3v3 -> VCC
GND-> GND
A0 -> Pot
Wemos D1 mini -> IRF520
D0 -> SIG
GND -> GND
Wemos D1 mini -> LCD2004
D1 / GPIO5 -> SCL
D2 / GPIO4 -> SDA
5v -> VCC
GND -> GND
Step 3: Put It Al in the Housing
So now it’s time to put it all in the housing. The displays is already mounted in there. You just put al the parts in, gently and that the signal parts are not touching. See the picture how i did it.
Also, this is the moment to drill the several holes for the connectors. In my case, I put the power in on one side, and the sensors / fan output on the other site.
Step 4: Software
The Wemos D1 mini should be flashed with ESPeasy for this tutorial, but you can use your own choice. How to install ESPeasy see: https://www.letscontrolit.com/wiki/index.php/ESPEa…
Configure all the attached devices to the right GPIO’s (see pictures for my configurations)
- Analog input (potmeter) to D0 / ADC (TOUT)
- Fan: GPIO 16
- BBQ sensor: GPIO15
- LCD2004 display: GPIO4,5,0
- Meat sensor: GPIO2
Task Settings
Analog input:
You need to configure the 1024 measurement points to “normal” degrees. I used 50 to 250’C but you can adjust this to your liking under “two point Calibration”. See pictures. Interval to 1 sec, value with 0 decimals
Temperature sensors (BBQ and Meat):
Measurement interval to 5 sec (does not change that much)
LCD2004:
Find the right I2C adress, this is some trial and error (or when you know the adress choose that one). Adjust display size to the right size (4×20). At the lines, fill in the desired text and values. See picture how I did this (it’s in Dutch).
Enable the rules under “Tools” and than select “Rules” and “Old Engine”.
Than make a rule, to control the fan (make sure your naming of the devices and the values are the same, otherwise it’s not working):
on Meting#Temperature<[Waarde#Analog] do
let,1,[Waarde#Analog]-[Meting#Temperature]
if %v1%>5
GPIO,16,1 //turn on fan
endif
endon
on Meting#Temperature>[Waarde#Analog] do
let,2,[Meting#Temperature]-[Waarde#Analog]
if %v2%>5
GPIO,16,0 //turn off fan
endif
endon
It’s time to test it! Be sure the ESP8266 can connect the wifi network, otherwise it won’t start up!
Step 5: Time for BBQ
