Just became a member

@banjobrad2

Welcome to the forum.

Please tell us more about your problem(s).

@banjobrad2 We were all new at one time, welcome aboard.

@banjobrad2

Welcome to the forum!

Don’t worry about how simple/hard your problem may seem.

As Ron said, we were all new at one time (some of us still are).

Tell us about your project, I’m sure someone on here will be able to help you.

Regards,

Lee

So @banjobrad2

Is that a five string or a four string?

Tom

@banjobrad2

Welcome banjo.

Ask away, looking forward to reading what your current problem is.

Regards

Ron B

@ronbentley1 Good morning Ron. What I would like to do is fab up a small ventilating system for a custom truck I'm building. It is a 1950 Chevy 3100 pickup which if you're not familiar has a few rows of louvers on the passenger side cowel in front of the door. This used to be where a fresh air heater was attached inside above the passengers knees. Since I am making the truck a bit more modern in appearance and functionality, I have an A/C/heat system which takes the place of the need for the old heater.

The idea I have is to fab a sheet metal assembly which would include a type of vent door, which would open with a hinge or slide like a rack and pinion setup. Not sure which way to go yet. Also on the inside of the door opening I will add a small DC fan which would be controlled by a potentiometer to draw air into the cab.

Watching one of Bill's videos on rotary encoders, I thought this might be a good approach. Use the Arduino, driver, encoder, and either a stepper or servo, looks like it could work for me.

The questions I have are; does the Arduino hold memory for the code so you don't need a computer to keep it alive? Also, since this schematic would be powered by a car battery, will I burn things up without adding something else?

Please advice on what you think would work best. I don't really have a clue about what I'm doing.

@banjobrad2 

Hi banjo, interesting project.

As far as arduino and esp 32 boards are concerned then they retain their programming once the operational code is loaded onto them, even over power off/on sequences, so no worries about losing set up data and config.

You do need to be careful connecting these boards to components that can draw a good lot of current, there are many tutorials giving good advice and guidance, especially dc motors. I'm sure that one of Bill's videos covers the issues?

👍

Regards

Ron B

Hi @banjobrad2

  Welcome ..

     You have already had some good advice , but I thought something @ronbentley1 stated might benefit from a little expansion, as although it is true, it assumes you already understand something. I apologise, if I am stating the obvious, and in no way, am I disagreeing with Ron's statement.

Re: As far as arduino and esp 32 boards are concerned then they retain their programming once the operational code is loaded onto them, even over power off/on sequences, so no worries about losing set up data and config.

The boards mentioned are programmed by connecting them to your computer system, and all of the details of the program, etc. downloaded at that time are indeed retained, when the power to the board is cycled. However, it is not normally 'conveniently possible' to remember something that changes whilst the board is in use.

I'll try to explain with a simple example...

-----------

Imagine your board controls a motorised valve (or vent flap), which may be 'open' or 'shut', and once moved to one of the these two states, it physically stays in that position until the motor is again energised to move it to the other state.

It is clearly not possible to include the state  for the state of the valve (shut or open) to be stored in the board program , as it changes when the board is running, and it may be in either state when the board power is removed. Thus, when the power is restored, the board will not know which state the valve is presently in.

It is feasible, to make provision for the board to write the state of the valve to memory every time it changes, but this is not the default case, and in general I would not recommend that path if an alternative exists. (How to do it and the problems involved, could be a separate lengthy forum thread discussion in its own right!)

Thus, I would recommend that the valve is fitted with a sensor (e.g. a microswitch), so that at any time when the program is running, the board can determine the state of the valve, and proceed to change it to the other state if necessary.

Best wishes with your project, Dave

@davee 

Nice one

Ron B

@davee   Thanks for the information Dave. If I use a rotary encoder for example to rotate the motor 180 deg., the vent door being closed at 0 deg. and wide open at 180 deg., I wouldn't care at what point it is opened when I shut off the power as long as I can resume turning the encoder one way or the other to accomplish open or closed once the power is back on. If for instance I leave the vent door fully open when I turn off the power, I'll know it's open the next time I get in and drive, so I'll leave it that way or turn the encoder ccw to close it. Does that make any sense or am I missing something?

@lee-g  Used to play the 5 string, just kept the old email address.

@banjobrad2 That would only work if you stored the last position in EEROM or some other semi-permanent memory. Keep in mind you could leave any small board computer of your choice on 24/7/365 and it would have no effect on a truck battery.

@zander   Thanks Ron, so if I want to keep things simple, I would wire this assembly to remain hot all the time. That would be fine for me. The other question I have is the current rating of an automotive battery vs. what it would be powering. Do I need to control this somehow?

@banjobrad2 No, current is drawn not pushed. However if a short occured in the right place then a problem could ensue. Stick a small 12V 2.5A fuse between the battery and the esp32 to be safe.