Bacon With a Blynk




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I've made a few smoker controllers in the past and monitoring tools to go with them.

I started playing with the ESP8266 because of its power to weight ratio. For a small board it packs a lot.

When I got a Sparkfun Blynk Board I decided to try a rewrite of my meat thermometer.

Step 1: Modifying Te Blynk Board

I soldered header pins into the Blynk board and made a simple shield using some sip header stock. I like the alligator clip accessible holes but these pins help with breadboarding smaller components too.

Step 2: Calibration and a Custom Case Too

Calibration was done by recording the raw adc values with the probe in ice water then in boiling water.

I also recorded a few more points as the water cooled down. I used the arduino map command with two points on either side of my target temp of 150. I saw some people who had rather elaborate equations to get the temperature but since I'm only interested in a narrow range the map seemed good enough.

Like others reported I too noticed a bit of heating of the internal temperature and humidity sensor so I added an external DHT11 sensor. Just nice to see the ambient conditions outside the smoker too. This heating may have been exaggerated from charging the large lipo I used.

The built in lipo charger is a big plus for this app.

I used the Blynk cloud server and had a working unit in just minutes. I later removed the graph since the temperature changes so gradually it always looked like a flat line. The history widget is what really shows the trend. I like that it also allows you to dump the date to a csv by email. Just slide it left....

The space made room for a slider to set the notification temp. I may add a separate slider for alarm temp. I'm thinking the alarm should be a relay output driving an old schoolhouse bell I found at a barn sale last year.

I decided to 3D print battery and shield trays to hold everything together. This makes it easy to pop off the Blynk for other uses.

Step 3: Making the App

First thing you need is a list of the variables used.

I used these Virtual pins:

V2 - Probe Temp

V3 - Probe Temp

V4 - Notify Switch

V5 - Alarm Switch

V6 - Alarm Led

V7 - Activity Led

V8 - Ambient Temperature

V9 - Ambient Humidity

With that list handy download the blynk app from the apple or android store and get started.

Here is a 3 minute video to help you along.....

If you'd rather just clone my app scan the QR code from inside the Blynk app.

Step 4: First Try

I started adding push notifications and an alarm to the code but I couldn't wait. I had to get one test run in. I paired it with a commercial meat thermometer to see how accurate it was.

Step 5: The Future?

I have issues with the GFCI popping on my smoker so I want to incorporate a Blynk board into the next version if the smokerduino. I'll use an opto coupler to monitor the main power supply and alert me to any power failures.

For now it works fine as a standalone unit.

I can just leave my ipad on the coffee table and watch the progress from the comfort of my recliner. The push notifications can also tell you if the board goes offline like when I unplugged its battery....



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    9 Discussions


    1 year ago

    QR Scan says the app is no longer valid or available.... Cant wait to start this. Blynk and I have troubles. I can get a BME280 to print to serial, but not BLynk ... Want to try the DHT11....


    Reply 2 years ago

    Thanks, I didn't get much of the Bacon... I'll have to make more after the new year....


    2 years ago

    I like the App you created with it. I'm not too familar with Blynk and how to use it. Could you provide more details on how to do this or am I missing something?

    Very Cool Project though

    2 replies

    Reply 2 years ago

    I added a step with a video of the Blynk app. Hope that helps....


    Reply 2 years ago

    Simple enough to do but hard to explain. I'll try to make a video of the app creation tonight. it wont be as good as some of the app creation ible's out there but I will show specific setup to this sketch...

    Its a drag and drop deal with a bunch of virtual pins referenced from the sketch.


    2 years ago

    Thanks for explaining this very cool project, makes me want to become a DuinoDweeb! I also use the Oneida thermometer but wish it could alarm when a temperature drops to a target temp: I use it for homemade yogurt and after a high of 182 F, I need something to wake me up when the milk drops to 110 F. Gotta hack it somehow since the manufacturer didn't.


    2 years ago

    Cool idea :) We've got one of those oneida thermometers and we love it!

    1 reply

    Reply 2 years ago

    I love those. I stick it to the range hood when deep frying or making syrup.