I was on the lookout for a BBQ / Meat temperature wifi probe that I can use in my oven and in the BBQ.
The main requirements that I want it to have:
ESPHome compatibel over WiFi
minimum 2 Probes, 1 for ambient temp in oven/BBQ and 1 for meat.
Battery powered with at least an evening of power. (can always be extended with powerbank)
Just pass on the data to HASS and control any settings (internal meat temp) and notifications from there.
Not willing to pay more than €100,- for such a probe and prefer my own hardware + ESPHome.
This is not a difficult thing to make and probably many tinkerers have done so.
But I cannot find any open source hardware / PCB / schematic for this.
My ideal situation would be that I can buy it as time is precious, for example like: Zuidwijk SlimmeLezer+ and this air quality sensor
I am therefore going to make one and plan to open source the hardware / sale the PCB.
In an effort to save time for other people.
Other options I want to add additional to the requirements above:
Piezo Buzzer to be triggered from HASS
Some LED’s to be controlled from HASS
Battery level data send to HASS, no indicators.
No screen, temp can be watched through HASS and I want to keep it simple, light, cheap, and easy.
External antenna, Wifi reception might not be good in everyone’s garden.
Questions I have:
I am thinking SMD to make it cheap to order PCBA and make it simple to order and make it accessible for non soldering skill people. Or THT to make it more accessible for DIY… What to do?
Are there any other requirements? Nice to have things? more probes?
Is there any interest in ordering or copying this BBQ Meat temp probe thing?
Thanks! I have looked at it, the INKBIRD IBT-2X is very cheap at €30,-
The projects that I find use or ESP32 or Raspberry Pi zero or App to grab the data from Bluetooth and send it to HA. I do not want to add another device between the Probe device and HA or use any app.
I also see some people have problems with stability of the Bluetooth.
The Inkbird devices look nice, but not for me.
Thanks again for suggesting them.
The first prototype works.
I will now have to wait for 2 weeks for some of the AliExpress parts to arrive.
Still need to add battery, test battery life, test SMD parts, design PCB, quotation and decide on what to order: PCBA vs PCB.
All the temperature probes I found seemed to be quite ‘fat’ - good for monitoring a space, but i want to be able to poke it in the meat itself to track the internal temperature.
I thought getting such a probe and grabbing its temperature reading would be simple but it turns out its not!
I had wondered about grabbing a cheap dumb probe off amazon and seeing if you can pick up on its output but i dont know if im up to it.
I will document the final version in a new topic in the ‘Share your Project’ sections and share the gerber file, part list and code so that anybody can easily reproduce or fork it.
I will probably have 10 pcs PCB’s as that is the minimum order, so I will be able to make a couple for some people that are not good with soldering.
Any progress will be posted here.
The Wemos Mini Pro was delivered, so I added it to the project and I made the schematic.
Next step is the battery test and the pcb making.
I am thinking of adding a USB-C port for charging as the battery connector extends further out than the micro USB on the Wemos Mini Pro…
The battery lasted 36 hours under the following conditions:
18650 battery. Not a clue about capacity of this one. Internet says they are between 2600mAh and 3500mAh
Measuring 2 probes with update_interval: 30s
Measuring battery voltage with update_interval: 60s
I used the on-board LED and the added piezo buzzer a couple of times just to play around with the kids.
In my use case a 1000mAh would be enough and a LiPo would reduce the thickness of the 3D printed box. This may be easy if you want to place this in a drawer under the oven for example.
The PCB is compatible with a 18650 or you can leave that out and solder a LiPo to the pins of the battery or to the on / off switch.
I have ordered the PCB and will receive it in approx. 15 business days.
In the meantime I can start designing the enclosure.
Stay tuned.
Quick update: The PCB looks nice, but did not read the MAX6675… The chips might not be good or the soldering… Wiring of the 2.5mm jack sockets was also not good…
Will now be switching to a module and order new PCB’s, which will also be easier to solder for other people to copy the design:
@PapaLancThe DS18B20 Temperature Sensor is rated to max 125°C. That is not appropriate for a BBQ or oven. You need a Type K thermocouple. It is indeed not difficult or hard, it is just that I messed up in the step from breadboard to PCB. I wanted to go fancy with SMD chips. But I think that I sourced the wrong chips through AliExpress and it is not a friendly solution for anyone that wants to copy the design. So I will go back to the breadboard, make new PCB and finish the project with a fancy box.
@nickrout Yes I am, the 2 black chips in the middle are MAX6675 chips and the probes connect via a 2.5 jack. Like many other Meat and BBQ thermometers do. It is therefore compatible with most general probes. Thanks for following the project.
yea, I do not know the diff between a thermocouple and a temperature sensor. For my case I was just looking for a meat probe and I figured a pointy end and a braided wire on the DS18B20 would fit my needs. I am thinking about a pellet grill that sets the pit temp. But it would be nice to have that temp from afar as well.
I have an egg with a BBQ Guru control, but looking at a pellet egg now. Kinda like turning on an outdoor oven.
I will be following as well.
Thanks,
Grey
I am not good at soldering either lol so I would be interested in a completed one
I use a DS18B20 to read the temperature of my pool and it works fine there. But it would be too big to mount in a probe that you want to stick in a piece of meat. Especially since it would want to be at the end of the probe to get meaningful temp readings.
Since thermocouples just use special wire material, its easy to make a tc probe that you can insert.
Being lazy, I may try the bluetooth inkbird, and add a esp32 to read it.
