Dumb waiter control ?

Thread Starter

surfguy

Joined Nov 30, 2023
2
Hi building a dumb waiter (myself use only) with of course multiple safety brakes and power cutouts.
question is
As im using a drum winch either 3 phase or single phase (not yet purchased) forward reverse/ground/1st floor/2nd floor
what do you members think,should i go down the Arduino board road and have someone program this with "alexa command.
or just use standard push buttons. I did hope to use Alexa as my control voice command if possable.
ground floor command would be
Call/send to 1st floor /send to 2 nd floor.
1st floor would be/ call to that floor/send to 2nd floor/send to ground floor.
2nd floor would be /call /send to 1st floor/send to ground floor
thanks guys
be nice please!
 

MaxHeadRoom

Joined Jul 18, 2013
28,513
If this is for Dumb Waiter use only and no personnel involved, and the usual safety requirements are taken care of, you could do it that way, but most can be done using simple relay logic.
 

Ya’akov

Joined Jan 27, 2019
8,973
Any safety concerns can be addressed by ensuring there is a door with a positive interlock that doesn’t depend on the MCU (Arduino) to operate (e.g.: it prevents movement mechanically or by removing power to the motor) and that there is no access to the hoistway during operation with absolutely direct interlocks on any access doors or panels.

An MCU is absolutely the right way to do this, and “Arduinos*” are excellent options because of the ease of programming. Careful design is far more of a concern than the presence of an ”Arduino“ and being sure that all safety features do not rely on anything that isn’t directly coupled and failsafe doesn’t mean you can’t use the Arduino as a controller.

Think of it this way: properly designed, the Arduino or any other MCU board you might use, will simply be controlling the top level behavior as if it was pressing the buttons on a preexisting dumbwaiter. The systems that provide safe operation could not be overridden by the MCU, only operated like a person operates an elevator.

This connection would include interfacing that would allow the MCU to ”know” the status of the dumbwaiter (location, idle/active, direction of travel, fault status, etc.). And the “intelligent” behavior of the lift would be dependent on the MCU. But, you could also provide buttons at each floor that operate the lift directly—and very nicely you could have these signal the MCU if it is not dead/locked up but revert to direct control of the lift if the MCU is offline.

As far as voice control through Alexa, that’s pretty simple and could be fairly sophisticated.

*The is no such thing as an ”Arduino“ in the way that it is informally used. Arduino refers to a development environment including an IDE (the code editor and controls for the compilation and uploading of code). But the development boards that are supported in the Arduino environment are extremely diverse and based on a large variety of MCUs (microcontroller units) which are small CPUs with integrated peripherals allowing them to interface to the real world through sensors in various ways.

A small minority of Arduino supported MCU dev boards can also be called “Arduinos” because they are designed by the Arduino organization—but that‘s very misleading when it comes to other options that are designed and manufactured by unrelated organizations and can be programmed in other environments.

Being an “Arduino”, when the term is loosely applied doesn’t tell you anything about capability or reliability of the device—only that programming can be done in the Arduino environment.
 

dendad

Joined Feb 20, 2016
4,426
One thing we usually include in our industrial control systems is a port pin that is toggled in the program loop, not from a hardware timer, and this signal drives a charge pump to bias a master FET that needs to be turned on before any outputs can be energized. This largely helps to prevent the system from locking up in an unwanted state. If the program crashes, the pulse stops and the power to the outputs is removed.
This and some other good design points go a long way to help make the system reliable. You may also add manual controls but have a key switch to lock this out so it needs the "Administrator" to use that function.
Hardware limit switches are a must too.
And an "Arduino" can quite well run this. Just make sure the power supply is well designed and I would recommend all inputs and outputs are optically isolated with the Arduino running on a supply that is also isolated from any contactors etc. that you use.
Many of our industrial control boards run of PICs and they are similar in capability to the Arduino chips.

Good power bypassing is your friend!
 

MaxHeadRoom

Joined Jul 18, 2013
28,513
As I'm using a drum winch either 3 phase or single phase (not yet purchased) forward reverse/ground/1st floor/2nd floor
Dumb Waiters are often implemented with less severe demands that personnel elevators do. but it is a good idea to plan for any event that may cause harm to either personnel or the system.
In the case of personnel or ride-along freight elevators that use the 3ph motor in its operation, a phase reversal detector must be used in the contactor control circuit.
Also, any flexible control cord/conductor that 'rides' with elevator motion, also has to have a stranded steel cable in its core.
I would tend to use a Picmicro, but the Arduino is similar in operation, i.e. either 8 bit or 32 bit processor.
 

MisterBill2

Joined Jan 23, 2018
17,788
There will need to be a fair amount of I/O , door condition, car location, and car call at each level, and at least two motor run outputs., and all of that will need to be quite reliable. So I suggest an actual PLC, which is already a more durable hardware package than most small-board micros.
 

MisterBill2

Joined Jan 23, 2018
17,788
Not necessarily so, if it is designed correctly.
8 bit Micro's are used extensively in both industrial applications and domestic appliances. etc.
NONE of the 8-bit micros that I have seen were in any package at all, other than possibly a PCB holder. And certainly most of theI/O connections are thin pins, although a few have actual terminals. So every bit would need to be packaged at least well enough to be field wired to the rest of the system. Un-packaged systems are fine on an experimenter's benchtop, most applications need a bit more protection.
 

MaxHeadRoom

Joined Jul 18, 2013
28,513
Well I usually build my systems around single micro and design the suitable board for the application at hand.
Whether it be for an embedded system or a stand alone controller, similar to a PLC with suitable I/O, Once the basic design is completed, it is very cost effective for future systems.
Industrial PLC's are fine for larger industrial applications, but if the application calls for specialized modules such as A/D or D/A, PWM or Servo etc, The PLC version can get expensive.
The amount of peripherals now included in most Pic's make it a very useful choice.
The OP apparently is building this for his own use, so I see no problem in a DIY project.
At the very most, the Smart-Relay would be a little more cost effective than the larger PLC.
 

MisterBill2

Joined Jan 23, 2018
17,788
The total expense is why I suggest investigating Automation Direct smaller PLCs that do not have analog options. At least most of them come with free programming software, or at least it is available free. Programming in ladder logic is fairly intuitive, and each I/O will have it's own name. Of course one must still know how the controlled item will work, but that should be simple for the one who built it. And knowing that from the start that all of the hardware I/O will work correctly with the processor and the program is quite a benefit. One added benefit is that the names of parts of the system are consistent with names used by others, so a program listing is always called a program listing, not a "sketch", and an expansion module is always called an expansion module, not a"shield". Speaking a common language helps communication a bit.
 

Ya’akov

Joined Jan 27, 2019
8,973
There will need to be a fair amount of I/O , door condition, car location, and car call at each level, and at least two motor run outputs., and all of that will need to be quite reliable. So I suggest an actual PLC, which is already a more durable hardware package than most small-board micros.
You are right that the MCU used to provide voice control through Alexa and other human interface facilities should not be the controller of the basic lift functionaliy.

But no one has recommended using the Arduino-compatible board for basic control or safety interlocking. The idea is to use relays, a PLC, or something similar for the basic operation and expose both high level commands (quite possibly only floor selection) and instrumentation (run/stop status, door status, location status, &c) as a simple interface probably using just a simple binary output for each possible state.

The human interface would be done by the MCU, including the desired voice control. It would also allow providing a smart phone interface and a status display.
 

dendad

Joined Feb 20, 2016
4,426
I would not use an Arduino alone, but as a component of the board as here in my Tracker HF radio synth.
TrackerVFO4S.JPG

An Arduino Nano could very well replace the PIC on a board such as this shown below, one of our networked 16 I/O cards that have been in service reliably for many years.
UMDC16_Small.jpg
The trick is to build it correctly. I shudder at the projects I see on line where Arduinos are pressed into service still on breadboards and jumper wires!


VFO_Delux_Both_Displays.jpg
Here is a board that has an ESP32 "brain".
The Arduino development environment is an easy way to start developing things and there is no reason why it should be less reliable than a PLC if the rest of the build is done correctly. In fact, many of the "Arduino" boards have a lot more grunt than the base level PLCs.
 
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Ya’akov

Joined Jan 27, 2019
8,973
NONE of the 8-bit micros that I have seen were in any package at all, other than possibly a PCB holder. And certainly most of theI/O connections are thin pins, although a few have actual terminals. So every bit would need to be packaged at least well enough to be field wired to the rest of the system. Un-packaged systems are fine on an experimenter's benchtop, most applications need a bit more protection.
There are, in fact, Arduino-compatible PLCs. The link is to LogicBus who offer three models.

Please keep in mind the requirement for interface to Alexa-based voice control. This would be most easily done with an Arduino-compatible or Raspberry-Pi-compatible board. I might personally lean to the RPi actually because of the operating system nature. It can run Linux or FreeRTOS.

In fact, the Milk V RISC-V boards are a very interesting option for this as well. Also with Linux or FreeRTOS. But, if the TS uses an Arduino-compatible PLC and an Arduino-compatible interface controller the consistency will probably simplify things greatly.

One more thing, there are DIN rail mounting options for various Arduino form factors, as well as DIN rail GPIO breakouts.
 
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