MAX6675 support

[node-alpha]

Added MAX6675 support -- Tested on Raspberry Pi (model B).

[abc2006]

After a couple of whiles i got it running on a RPI3ModelBVer1.2: connect SCK: PIN 23 SPI_CLK GPIO11 CS: to PIN 24 SPI_CE0_N GPIO8 S0: to PIN 21 SPI_MISO GPIO9 VCC: to PIN 1 GND: to PIN 6

Use following Program:

!/usr/bin/python

from max6675 import MAX6675, MAX6675Error import time

cs_pin = 8 clock_pin = 11 data_pin = 9 units = "c" thermocouple = MAX6675(cs_pin, clock_pin, data_pin, units) running = True while(running): try: try: tc = thermocouple.get() print("tc: {}".format(tc)) except MAX6675Error as e: tc = "Error: "+ e.value running = False print("tc: {}".format(tc)) time.sleep(1) except KeyboardInterrupt: running = False thermocouple.cleanup()

Thanks Draco for your Work!

Greetings, Stephan

[henrique-rsilva]

Hello guys, @node-alpha @Tuckie @abc2006 @dlleigh

Look, there is a short script in the link:

https://github.com/Tuckie/max31855/pull/4/files

Which is the sample in the documentation for max6675:

---

MAX6675 example

!/usr/bin/python

from max6675 import MAX6675, MAX6675Error

cs_pin = 24 clock_pin = 23 data_pin = 22 units = "c" thermocouple = MAX6675(cs_pin, clock_pin, data_pin, units) print(thermocouple.get()) thermocouple.cleanup()

---

This snippet of code above doesn't work, at least, for RPi 3 B v1.2

See:

There are two ways of adress pins in the Raspberry Pi.

GPIO.Board -> references the physical numbering of the pins GPIO.BCM -> is the Broadcom Soc Channel numbering (eg.: GPIO04 .....)

In the library max6675.py implementation, you need to pass the BCM pins.

The code below works well to me at Rapberry Pi 3B (Thanks @abc2006, your tip helped a lot).

---

!/usr/bin/python

from max6675 import MAX6675, MAX6675Error import time

cs_pin = 8 clock_pin = 11 data_pin = 9 units = "c"

thermocouple = MAX6675(cs_pin, clock_pin, data_pin, units) running = True

while(running): try: try: tc = thermocouple.get() print("tc: {}".format(tc)) time.sleep(1) except MAX6675Error as e: tc = "Error: "+ e.value running = False print("tc: {}".format(tc)) time.sleep(2) except KeyboardInterrupt: running = False print("\nStopped by User\n") thermocouple.cleanup()

---

@node-alpha , to make the life easier, i'd suggest:

In this part:

Initialize needed GPIO GPIO.setmode(self.board) GPIO.setup(self.cs_pin, GPIO.OUT) GPIO.setup(self.clock_pin, GPIO.OUT) GPIO.setup(self.data_pin, GPIO.IN)

Please, change this name --> GPIO.setmode(self.board)

This causes a lot of confusion, because you did in the init:

==> board = GPIO.BCM

It's not cool to keep like that.

Because you put together two ways to adress pins at RPi. And this mixture is confusing the way you did.

I hope it helps.

Thank you very much for your work.

Regards,

Henrique

[nilu0007]

Can we measure negative Temperature