I have some questions about connecting up my Heater Controller Project. I think I'm going to use a Feather M4 Express and Circuit Python. Drawing is attached.
Features of the system:
-Microcontroller is Feather M4 Express. https://www.adafruit.com/product/3857
-System is powered by 12V DC External Supply.
-Variable regulator for 3.3V components & Feather http://www.hiletgo.com/ProductDetail/1958344.html
-2 Inputs. Momentary pushbuttons. Setpoint Up and Setpoint down
-1 Analog input from potentiometer for fan speed control
-1 PWM outptut to a FET for fan speed control
-2 Digital outputs to relays for Fan and Heater https://a.co/d/7omtvKV
-Note that the fan has two controls in series: PWM for speed and relay for on/off[/list]
-I2C connection to Temperature Sensor MCP9808https://www.adafruit.com/product/1782
-I2C connection to OLED monochrome 128x64 (https://www.adafruit.com/product/938)[/list]
My question for today is which pins on the Feather are best to connect:
#1: Pushbuttons. Digital inputs. (if they have internal pull-ups, I can eliminate my external pull-ups)
#2: Relays. Digital outputs. high side or low side drive?
#3: Potentiometer. Analog input voltage 0 to 3.3V
#4: PWM output to FET gate (could use a series resistor if recommended)
#5: Power for the feather. 3.3V -or- slightly higher -or- use a dropping diode. Vbat - or- Vusb -or- 3.3V
Note: In the drawing I didn't connect the push buttons to the Feather and the other connections to the Feather are just placeholders - I'm open for guidance.
Feather Connections
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dogolearn
- Posts: 25
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Feather Connections
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dastels
- Posts: 15831
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Re: Feather Connections
Overall it looks reasonable.
1. You would set the digital inputs to have internal pullups so the buttons cam go between the pin and ground. Depending on how they are used you might want to consider using the debouncer module to clean up their signals (see https://learn.adafruit.com/debouncer-li ... ns-sensors)
2. " IN: high level control relay suction" So... a logic high engages the relay?? You will have to experiment. Also, some reviews said that it doesn't work so well with 3v.
3. What's the question? Consider whether you want a linear or logarithmic pot.
4. I've never used FETs much, but a little research and experimentation will sort it out.
5. I was wondering about this. The breakouts should be 5v powerable (confirm, but most Adafruit breakouts are) and it's best to power the Feather with 5v through the USB connector. The pot would be between ground and the 3v output on the Feather. As mentioned above, it sounds like the relay boards work better with 5v.
Dave
1. You would set the digital inputs to have internal pullups so the buttons cam go between the pin and ground. Depending on how they are used you might want to consider using the debouncer module to clean up their signals (see https://learn.adafruit.com/debouncer-li ... ns-sensors)
2. " IN: high level control relay suction" So... a logic high engages the relay?? You will have to experiment. Also, some reviews said that it doesn't work so well with 3v.
3. What's the question? Consider whether you want a linear or logarithmic pot.
4. I've never used FETs much, but a little research and experimentation will sort it out.
5. I was wondering about this. The breakouts should be 5v powerable (confirm, but most Adafruit breakouts are) and it's best to power the Feather with 5v through the USB connector. The pot would be between ground and the 3v output on the Feather. As mentioned above, it sounds like the relay boards work better with 5v.
Dave
Please be positive and constructive with your questions and comments.