I am working on a dust monitor system for my wood-working club.
Most pieces of the solution are working well: Dylos air quality monitor DC1100; Arduino - Uno with Wifi (Jaycar XC4411) and some VB.Net code running on the club PC to receive data and store it prior to later analysis.
It runs continuously and what I now want to do is turn the Dylos on and off to extend its life as we only need it running about half the time.
The On/Off switch is a soft rubber push button. The options I can think of are:
Solenoid. Probably the simplest but I am a little wary of the violence of asolenoid damaging the Dylos. I suppose with careful positioning and some sort of rubber-or-similar buffer between plunger and switch it may be OK.
360deg Servo. One of my first ideas until I found you can’t send these to a position, you can only make them rotate and stop. In addition to a cam or similar to operate the switch, I would also need a second cam (or just second lobe) to operate a limit switch to stop the rotation.
Stepper Motor. Suggested by Trent at Core. I have used these before and I think I could make it fit my need. My main worry is that they use four pins and - after RTC, an SD card and several serial connections I am not sure I have enough pins.
Any thoughts or suggestions would be very welcome.
To Liam, Thanks for your input but I don’t quite get what you mean by “open up the controller and solder in some connections”. Also, I assume by “servo motor” you are talking about the same device I referred to as a 360deg Servo.
To Rob. Also thanks for your input. Work for turning it off. Having done so, one then needs to switch power back on again AND press start button.
Thought that might be the case. Just a thought. Back to the drawing board.
I think Liam may have been referring to a “normal” servo, one that you can move a specified distance then move it back again. I think the “360º” servos are the exception more than the rule as the (old) saying goes. The majority of servos move back and forth in a 180º arc. The 360º ones are special.
Ooop, definitely could have been clearer here, one option I think could be to open the enclosure for the control board where the start button is and add a connection across both leads of the button then using the analog switch you can emulate a button press using an external power source and signal.
Yeah, I definitely agree that the 360 ones are an exception especially in a control systems point of view.
Opening up the Dylos box and bringing some wires out to which I could connect a switch of some sort was my very first thought and I got the screwdriver out immediately. Unfortunately, there is no discrete and separate switch inside the box. The rubber “button” has what I guess is a carbon coating across the inner face and - when pressed - this comes into contact with an area of the printed-circuit board coated with stripes of a similar-looking material. So, while soldering some jumper wires onto switch terminals was OK, I was not willing to do so onto a finely-detailed PC board. I was concerned both with the risk of damage and the impact on warranty.
The idea of using a traditional servo with a backwards-and-forwards motion is a good one. I just happened to have some 360deg ones from another project so that was where my mind began.
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