I have a short question about a small project a like to start. But first some additional information. ;D In my house I have several windows with ventilation shafts.
Because it is really hard to reach the ventilation shaft (too high), I like to automate this part of the window. Moving the switch up and down does not require a lot of force.
My question is: what hardware/software do I need to automate this part?
My functional requirements are: Small in size, Low on voltage (e.g., battery consumption, fire hazard, et cetera) and easy to mount.
Thank you very much in advance for your answer(s). All help is welcome.
I don't know how to quantify how much force is needed to flip the ventilation switch, but it is fairly easy to do (almost no force is needed).
What I am looking for is a kind of basic kit-list regarding my functional requirements.
Can you help me make it, so I can make a quick start? Programming is not a problem for me, but I do not know what hardware I have to buy.
I am thinking of an:
Actuator to flip the switch
Battery holder and battery case (I don't know how much batteries and which type).
A servo may be sufficient, and they are very easy to use with an Arduino.
However it may be possible to meet your requirement without any Arduino - just a small geared motor and a DPDT switch. One of the little N20 gear motors would probably be sufficient with an arm fitted to the shaft as with a servo. If you choose the length of the arm carefully and connect the arm to the ventilator lever with a push-pull rod the motor should be safely able to run continuously opening and shutting the ventilator until you release the switch. The output shaft of the little N20 gear motors rotates slowly.
Thank you for your feedback.
Unfortunately I forget to mention one important requirement. I like to schedule opening/closing the switch automatically.
Every morning 30 minutes for example. Is this also possible with the solution that you proposed?
hanss_arduino:
Every morning 30 minutes for example. Is this also possible with the solution that you proposed?
That makes it a bit more complicated.
If you want every ventilator connected to a single timer that would mean a lot of wires - but technically simple. The complicated bit would be making a simple timer stop the DC motor when the ventilator is open. Stopping it at the right place is trivial for a human. You could add limit switches that would detect when the ventilator is open or closed - but that also adds complexity.
Using a servo has the advantage that it moves to a position so it is easy to move to open or closed. But to move a servo you need an Arduino or equivalent. Actually one of ESP8266 boards (such as a Wemos) might be a better choice. They can be programmed with the Arduino IDE and they have WiFi as standard so maybe you could send a message by WiFi to open or close the ventilator. An Arduino such as an Uno or nano is not good at keeping time over long periods and with WiFi the device could get the time from the internet.
The other advantage of the simple DC motor is that it uses no power at all when it is not moving. if you have a microprocessor it will be using a small amount of power all the time.
I have the following components at home: - zc-a0591 (Stepper Motor Driver)
- Arduino nano R3 clone board (3.3v) - esp8266 (wifi module) - an external battery holder for 2x1,5V or 1x9V - 28byj-48 (5V stepper motor)
Is it possible to make this work with these components? And can I save the configuration so it stays, even after a powerdown?
I more keen to use batteries instead of an power adapter (just in case of fire behind the curtains).
I don't know anything about a zc-a0591 Stepper Motor Driver or whether it is suitable for a 28BYJ-48 motor. Those motors usually use a ULN2003 as the driver.
The problem with a stepper motor (compared to a servo) is that it never knows its start position. You would have to have some means to set that. The usual way is to have a limit switch and drive the motor so it triggers the switch and establishes the ZERO or HOME position when the Arduino starts.
Also a servo has all of its electronics inside so it does not need a driver.
The nano has EEPROM memory that can remember things when power is off. I presume the ESP8266 also has. That would allow you to store either a 'O' for open or 'C' for closed. Note that the EEPROM is only good for about 100,000 writes but if you had (say) 8 per day it would easily last 34 years (if my maths is correct) without even bothering with wear levelling.
You may get away with only needing to set the home position for the stepper motor the first time you set it up if it just works between two positions. And you may be able to do that manually (i.e. without a limit switch). However there would always be a risk of it missing steps and ultimately being in the wrong position. I would certainly prefer to have a limit switch that would be checked at every startup before going to the stored position.
Besides the forces involved to move the shutter each direction, you need to measure the actual distance the lever is moved, so you can compute the arm length on your motor in order to get the correct movement. The forces involved to move times the arm length will tell you the TORQUE needed for your motor.
The left hand one is a linear actuator, AKA solenoid. The other is also a linear actuator, but is much slower and the position can be controlled and stopped anywhere between the closed and fully extended position. A solenoid is all the way, immediately, or nothing. If the solenoid has a spring return, then it will automatically return to the home position when the operating current is removed.
Okay. Thank you very much for all the answers.
Maybe that some testing this weekend will give me a better view about how to build a proper and solid solution.
Paul_KD7HB:
The left hand one is a linear actuator, AKA solenoid. The other is also a linear actuator, but is much slower and the position can be controlled and stopped anywhere between the closed and fully extended position. A solenoid is all the way, immediately, or nothing. If the solenoid has a spring return, then it will automatically return to the home position when the operating current is removed.
It's hard for me to say how much force is needed to flip the switch, but it takes almost no effort (5 cm from up to down).
Does anybody know which motor I can use best for this solution (5V or 9V)?
