(Coffee) Easy way to get Arduino talking via BT through MODBUS protocol?

Hey all,

I designed a quick and simple circuit to monitor temperature via a MAX 6675 chip and a K-type thermocouple and output the results to an LCD screen. It worked well, I have it measuring temperature of a coffee roaster. However, the only way to mount it on the roaster meant the whole setup would be rotating so I couldn’t hook it up to my computer (that is why I had it output to an LCD screen). The code was as following:

#include “max6675.h”
#include <LiquidCrystal.h>

int thermoDO = 4;
int thermoCS = 2;
int thermoCLK = 3;
LiquidCrystal lcd(12, 11, 10, 9, 8, 7);

MAX6675 thermocouple(thermoCLK, thermoCS, thermoDO);
int vccPin = 5;
int gndPin = 6;

void setup() {
pinMode(vccPin, OUTPUT); digitalWrite(vccPin, HIGH);
pinMode(gndPin, OUTPUT); digitalWrite(gndPin, LOW);

Serial.println(“MAX6675 test”);
// wait for MAX chip to stabilize

void loop() {

lcd.print("Temp = ");
lcd.print("F ");


I also used some other code that was a version of one of the attached files when I had it hooked up to my computer to send the temperature readings via MODBUS to a program called Artisan Roasterscope. It worked, but obviously I couldn’t have it hooked up. I was wondering if there is a simple way to get it to output to Artisan over a Bluetooth transceiver (https://www.amazon.com/gp/product/B01CKW4FSI/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1). I’m not sure how this stuff works over Bluetooth. Do I simply run the code as normal once I have connected the Bluetooth device or does it need modification to the sketch?

MODBUS uses the slave command…does this work with the Bluetooth device being a slave device also?

Here’s the code that connects to MODBUS: coffee-roaster/sketch at master · lukeinator42/coffee-roaster · GitHub