Dog Health Tracking Device, the DogBit

I am a student at Howest studying MCT. Which means I had to make an IoT project at the end of my year. I decided I would make a health tracker for dogs, a lot like a FitBit for us humans. So decided to dub it "DogBit" (incredibly original, I know). With the DogBit you can track your dogs location, heartrate, step count and you can also track how hot or cold it is outside. I chose this project because I wanted to be able to track what and how my dog's doing. In this instructable I will guide you through the steps I took to create this project.

github

1 x esp32

1 x raspberry pi 4 model B

1 x GPS

1 x AD8232 (ECG)

ECG pads, 3 come with the AD8232

DS18B20, temperature sensor

1 x MPU-6050

LDR, use in combination with a 10k resistor

XT60 connectors to connect the power jacks to the battery

LiPo battery, the battery is 24 mm high not 32mm as specified

breadboard power supply, you can also use a voltage regulator, I prefer the breadboard power supply because it has 3.3 V and 5 V output, this saves me some work and avoids mistakes

power jacks, to connect the battery to the power source

cable sleeve, to keep cables sticking out of the encasing clean

dog harness, preferably already with Velcro

resistors

pin headers

soldering board, this one almost fits perfectly into the encasing

circuit protector

There are two parts to setting up BT communication. The raspberry part and the esp part. I used BT communication between the raspberry and esp32 but don't let that stop you from using wifi ot LoRa.

The esp part

This part is probably the easiest part.

• the BluetoothSerial library should already be installed if it isn't install it
• then just upload the SerialToSerialBT example to your esp32
• the esp32 should now be discoverable

The raspberry part

This part can get tricky but there should be no problems.

To get into the BT interface we have to use

bluetoothctl

After that use the following commands in this order

agent on
scan on

you will now see devices start appearing, when you see the one you want to connect to use this command to pair to the device

pair "mac address"

Then connect

connect "mac address"

To connect/disconnect a device, I wrote a library to help you connect to paired devices you can find it here.

I used this code to test the BT connection.

When that works we can proceed to the next step

Next up, the circuit. There is nothing to difficult but just make sure you don't short anything because LiPo batteries don't deal well with shorts, if you use a circuit protector or if you use another power source while building, you should be fine.

When the circuit is complete and you have checked it doesn't short we will start programming the components.

You can find my esp code here.

you will have to use the Wire, OneWire and FastLed libraries to code the components.

Temperature sensor

With the OneWire library comes an example code for the temperature sensor we use, with a bit of modifying we can make it run a lot faster, in its default state it would take far to long to measure temperature to be useful to us.

After you can get data from the temp sensor, try and print it out on the pi to make sure you can send it over BT.

Gyroscope/stepcounter

Now we will write code to count step using a gyroscope. To do this we will use the Wire library, I used the code you can find on this website to write my own code. I noticed that the code on the website was a bit buggy so fixed that and then broke down the code to the parts I needed and then wrote some functions to make using the senor easier.

ECG

The ECG doesn't require any libraries. You can find source code and a circuit on this site if you want to test the ECG individually. To get the heartrate from the ECG you simply have to write code that detects the peaks (marked as R on this site) and measure the time between them, each of this peaks is a beat

GPS PA1616s

Coding the GPS was probably the most fun of all components. You can use Serial ports to communicate which makes this rather easy to read data from. You can extract the necessary parts from my code here

LDR

I wont go over the LDR since it's too easy

The LEDs/Neopixels

We want to code the LEDs so that their brightness is dynamic with the intensity of light around us. The fastled library makes this rather easy, when using RGB just lower all values to go less bright, in case of HSV lower the V value to decrease brightness. I also wrote some code so they aren't always on and don't flicker when near the neede value to pass the if statement.

I used fusion 360 to design an encasing for the DogBit. It is too small to contain all of the cables so to cable to power the breadboard power supply sticks out as well as the LEDs and the stepcounter. I used a 3D printer to make this encasing, it's printed from PLA.

you can find the file here.