[harryn]

Hi, I have a single axis project and would like some suggestions.

We make a fair number of wires with crimped on ends with heat shrink tube over the crimps. The heat shrinking is done by putting the ends into a heat gun.

While it is possible to just "put the end into the heat gun area", it works better if the motion into the heat area is done in a controlled linear fashion and I would like to automate this process.

It is not one constant speed - more like"
- move about 3 inches
- stop for 5 seconds
- move slowly for 2 inches
- stop for 3 seconds
- move 2 more inches
- stop for 5 seconds
- slowly reverse to original position


What I have in mind is a simple, single axis motion with the ability to program in the X axis motion, ideally without needing to resort to a computer to run it.

I have a Gecko 213V and actually a gecko stepper motor from back when they sold those, so it is ideal if that can be used for the project but if Gecko offers something else that makes sense I am open.

Any suggestions for how to run the drive? I guess I am looking for a simple way to create 5 volt pulses to feed the stepper driver.

I thought about using an arduino or beagle bone - have them but don't know how to use them. Frankly, not sure I want to take the time to learn.

Would a PLC be easier?

I am not against hiring someone if it makes sense.

Thanks

Harry

[rodw]

There are many Arduino scripts to drive rotary tables but not many that do linear movement. I have written one that does both and supports multiple devices (where a device can be defined as linear or rotary). Some people have used it to index on a mill that does not support a 4th axis by running a tool past a proximity sensor in the Gcode to trigger a switch. This week, a chap who wants to use it to drive his camera up and down a rail. His requirements were simpler. He just wanted to have continuous movement when he held a button down and move a defined distance whenever he pressed a button. It supports that without any modification. This is a high performance interrupt driven solution which included trapezoidal acceleration profiles

You can grab the code here
Interrupt Driven Rotary Table controller - Home Model Engine Machinist
There are some hardware dependencies so read the thread carefully.

This will need some modification to meet your requirements. Have a play with it, If you would like me to customise it for you for a fee, I am open to that too, Just send me a PM.

[harryn]

Wow Rod - Thank you.

I did an initial read of the link and re-read portions of the gecko manual and arduino specs - looks very viable.

I have not written any code since Fortran WATFIV so this will be immensely helpful.

Let's see how far I get with the initial setup and then we can go from there.

[rodw]

You are welcome. If you can program in FORTRAN, C will be easy to pick up but object oriented methods may be new.

You will probably need to remove some features to regain enough global memory to add your menus. The problem with the Arduino is that strings defined in the code are copied from the static flash code memory space into global memory variables so they become read/write. Then we run out of global memory and behaviour becomes erratic due to memory overwrites. Thats why some of the menu options are cryptic.

The Arduino supports the PROGMEM variable modifier to prevent this happening and leave the strings in the program memory where they are read only (perfect for menu text). The biggest contribution somebody could make to my code would be to modify the 3rd party LCD class so that it accepted PROGMEM variables for menu prompts so that text prompts are no longer the limiting factor.

I was hoping to add an SD card and some sort of macro programming language so that you could write your command sequence in a text file on a PC, copy it to an SD card and pop it into the Arduino to do what you want to do but the global memory became the limiting factor which prevented this.

And yes, the Arduino has a 16 MHz clock so in theory, can support a maximum step rate of 8 Mhz (on/off states) so it has more than enough headroom for any conceivable stepgen application and more than enough to drive a 10x microstepping Gecko drive which will be in the kHz range.

[A_Camera]

Just driving a stepper in/out is very simple. You can do that with a 555 and a few capacitors/resistors, one button and one switch. Really, extremely simple. You can add two end stops as well to make sure it never runs further than needed. But you need to have some basic electronic knowledge. If you want to make it more intelligent and perhaps automatic, you can use an Arduino board and with the Marlin 3D printer firmware you are up and running in no time. All you need is one axis, so no need to make full use of it. You can have an LCD display and an SD card reader, and can write a simple G-code to run it automatically from the SD card if you don't want to use a PC. But in this case you need some basic electronic knowledge as well as some programming knowledge... Nothing is plug-and-play, so unless you find a ready made solution, you have to do some home work on your own or hire someone to do it for you.

One idea if you don't want to learn... Contact a local high school or university. There you'll probably find some electronics/programming geeks who can definitely help you out if you describe your problems. Maybe someone there can do it as an extra weekend job. This is really a simple task which can be done by any 15-16 years old kid interested in electronics/Arduino.

There are other possibilities as well but all needs some effort from you or someone else.

[harryn]

Hi Rod, the last time I programmed in Fortran was using punch cards around 1980 and the furthest I ever got was solving a few simultaneous engineering equations. As I moved from being a chemical engineer into process work, the PLCs were already mostly in place, and those are easy to program. In various sales roles, the software was mostly office related and I am more of a hardware guy.

You are right, the more ideal situation is if parameters can be set easily from the screen. I wouldn't mind being able to dig in deeper along the way, but I am trying to find something as a base case to get moving more quickly.

As far as learning, it isn't that I am afraid to learn - I developed and my company now builds mobile auxiliary power units / drop in electrical systems that are used in conversion vans and disaster zones, it is just that we are trying to ramp up production and I already wear multiple hats.

A few years ago I purchased raspberry pi, arduino, and beagle bone black boards for my kids for Christmas, hoping to kick start the experience, but it didn't stick. Not sure of now, but at that time, it seemed like the beagle bone black was potentially better for hardware i/o control than the others.

[harryn]

Just driving a stepper in/out is very simple. You can do that with a 555 and a few capacitors/resistors, one button and one switch. Really, extremely simple. You can add two end stops as well to make sure it never runs further than needed. But you need to have some basic electronic knowledge. If you want to make it more intelligent and perhaps automatic, you can use an Arduino board and with the Marlin 3D printer firmware you are up and running in no time. All you need is one axis, so no need to make full use of it. You can have an LCD display and an SD card reader, and can write a simple G-code to run it automatically from the SD card if you don't want to use a PC. But in this case you need some basic electronic knowledge as well as some programming knowledge... Nothing is plug-and-play, so unless you find a ready made solution, you have to do some home work on your own or hire someone to do it for you.

One idea if you don't want to learn... Contact a local high school or university. There you'll probably find some electronics/programming geeks who can definitely help you out if you describe your problems. Maybe someone there can do it as an extra weekend job. This is really a simple task which can be done by any 15-16 years old kid interested in electronics/Arduino.

There are other possibilities as well but all needs some effort from you or someone else.

I thought about using 555 timers and did that in the past for a single frequency of pulses. Easy to push a button and start making a pulse train. How do you make it go through stops / starts / reverse without needing to add on a controller or multiple switches along the way?

If it is going to take more than a few days of work, it is easier to just buy a cheap computer and set up a linuxcnc arrangement. With all of the motion control interface boards out there to interface from USB / ethernet to digital i/o I figured there must be one that I could just download some g code steps from a pc and it would run a loop. (don't care if it is 1 vs multi axis)

Mostly I am trying to save space vs money. Our electronics assembly area is already pretty busy and having to add a computer + interface boards, etc just to run a simple single axis seems silly. Also, most consumer computers aren't designed to be dropped which is certain to happen based on my cell phone experiences.

[rodw]

Well, Grbl or TinyG on the Arduino platform or
Machinekit, a fork of LinuxCNC on the Beaglebone Black (but apparently they marry it up with a PC as well)
LinuxCNC with a simple parallel port is an option
Of those options grbl is probably the simplest as you just need an Arduino Uno
LinuxCNCI know very well but the others I have no experience.

[harryn]

Thanks for the inputs and ideas.

I also found the planet-cnc controller that acts as a buffer / controller between for example a windows or linux computer and the gecko drives. It deals with the signals from usb or ethernet and creates the required pulses.

Interestingly it appears to have an option to download the g code onto an SD card and run without a computer as well if I am interpreting things correctly.

Not cheap but would be another possible solution if I am understanding the product.

[rodw]

Even a Chinese stand alone CNC controller might be a good option. This one accepts a micro SD card. and its only $160