Will this hardware work for a start

Planed purchase to start project--
uno wifi, incremental rotary encoders (AB two phases), relays for 12V 10amp, micro switches, and use current android tablet for HMI.

Will an Arduino uno wifi process high speed input from a rotary encoder?
Will an android tablet as HMI be able to send multiple commands (virtual buttons/switches) back to the uno?

I figure to start with having system just tell me distance to bed and distance moved since last set.

Then to just move head up and down with HMI

Then to have system move the head a specific distance via buttons on the HMI.

So it will need to read pulses from encoder, compute distance, activate 2 to 4 relays, and not allow over travel.

Eventually I would like to control all functions that are now controlled by manual switches. But there are only 7 manual switches and I may not need the seventh.

I am sure I am missing stuff but hopefully you get the idea. Will my item list get me started or do I need different or additional components?

The project --- I have a hobby sawmill that is all hydraulic, the main functions I would like to automate are now controlled by hydraulic valves that are activated by 12v DC (push buttons and toggle switches). To start with I would like to control the head up and down function then move on to other functions.
I do not want to just move the head up and down, I want to have it move up or down a specific distance.

Thanks for all the help so far.

Depends on e.g. what you consider "high speed".

DrDiettrich:
Depends on e.g. what you consider "high speed".

I am a noob, I have just read that to use an encoder you need a controller that can take high speed data. Nothing ever mentioned what speed. For my purpose I would guess 1000 pulses every few seconds. Maybe 300 pulses per second. I can slow it down if needed.

That's low speed even for a 16MHz controller.

I would think that what you are trying to do is within the capabilities of the Uno WiFi.

This hobby is about learning so experiment and find out what works. Ask if you get stuck.

Don't worry if you find out you got the wrong parts, as long as you learn from what you have tried.

Enjoy.

As I replied in your other thread, this is a very doable project for Arduino. Your most difficult part of the project will be getting the encoders mounted to return the absolute position of the saw heads.

SteveMann:
As I replied in your other thread, this is a very doable project for Arduino. Your most difficult part of the project will be getting the encoders mounted to return the absolute position of the saw heads.

I was hoping to lower the head to the bottom and use that as a home position every time I start the electronics. That would place the head 1" above the bed. Then use all measurements from that point. Does that sound workable?

PerryBebbington:
I would think that what you are trying to do is within the capabilities of the Uno WiFi.

This hobby is about learning so experiment and find out what works. Ask if you get stuck.

Don't worry if you find out you got the wrong parts, as long as you learn from what you have tried.

Enjoy.

This is what I kind of figured. I like learning new things. I counted on having to replace parts and upgrade parts as I went. I just didn't want to get in to deep ($) before proving the concept. I plan to have this on the bench for quite a while before I ever put it on the mill. I have a couple of months before the cold weather lets up any way.

woodman52:
I was hoping to lower the head to the bottom and use that as a home position every time I start the electronics. That would place the head 1" above the bed. Then use all measurements from that point. Does that sound workable?

That's one way. some 3D printers do something similar where the print head moves until it touches the bed, and that becomes the zero point for the Z axis. It doesn't really matter what you use for the zero point reference as long as it is repeatable.

As I said, the mechanics of connecting an encoder to the saw heads is going to be your biggest challenge. Get that solved and the control software is fairly straightforward.

In the past Century, I was a programmer with a company that "automated" sawmill operations. I wrote the code that would determine ("guess" is a better term) what kind of log was coming down the line based on the roughness of the bark using optical sensors. The code also determined the minimum diameter of the log, then set the saw blades for the maximum yield. It was fun to watch. All of the code was written on assembler code on a DEC PDP-8.

woodman52:
This is what I kind of figured. I like learning new things. I counted on having to replace parts and upgrade parts as I went. I just didn't want to get in to deep ($) before proving the concept. I plan to have this on the bench for quite a while before I ever put it on the mill. I have a couple of months before the cold weather lets up any way.

I have boxes of sensors and components used once.

SteveMann:
All of the code was written on assembler code on a DEC PDP-8.

I am sad (but of course, my wife would not concur :grinning: ) that I never got my hands on a PDP-8 when the university disposed of them. First computer used at a maths weekend in final year of high school programming in FOCAL.

I’'d like to have a pdp-8 for playing Lunar Lander :slight_smile:

There are PDP 8 parts on eBay, couldn't see a complete computer.

Wasn't the pdp-8 also one of the first computers on a chip?

As to viability of the hardware suggested, it'll certainly get you started. For the fully functional version, I suggest you count pins. A regular Uno has 19 pins that can do digital operations. I'll guess that wifi consumes four of them. You will need serial for debugging, so that's another two gone.

You want to operate seven switches (a pin each) and detect a microswitch for homing. That leaves five. I expect you'll need others for things not yet specified. Port expanders can help or you can get something with more pins.

For you PDP-8 fans, I saw that someone is selling a PDP-11 emulator including a front panel to toggle in the bootloader. It has a Pi inside to do the work. Perhaps there is a way to relive your PDP-8 glory days too :slight_smile:

Oscar Vermeulen has produced a kit with a front panel reproducing the PDP-8 (so it is not surprising that there would be the same for a PDP-11) with suitable lever switches and all. Of course, there is no "depth" behind and the actual processor is a Pi. :grinning:

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