Category: Uncategorized

Posted on

GRBL 3d wire bender, Part 6 : What does it really do?

So I’m finally getting back to updating and using the GRBL wire bender, so I have to actually use it for something. I had built it to be able to bend various springs, when I can’t get ahold of exactly the right spring, so let’s go though a basic spring design. The other use is for bending copper wire into antenna shapes, but that’s further down the spiral…

Types of springs

Each type works a little differently in the code so let’s start with some definitions:

Types of springs for the machine

The bender really only can do springs made of wire, so disc / Belleville springs, and leaf springs don’t even enter into this conversation, so the types I’m targeting is:

  1. Tension Springs
  2. Compression Springs
  3. Conical Springs
  4. Spiral Springs
  5. Torsional Springs
  6. Compound variations of above

Spring construction

The spring body

All of these types start with a coil of some sort, as the base and then some sort of legs, The coil could be flat, as such as a spiral spring, close together like a tension spring, spread apart like a compression spring, or a lofted spiral like a conical spring. The wire diameter, the number of coils and the spacing between the coils changes how the spring responds

The legs

The leg styles are basically three different styles, there is a straight wire, a straight wire with a hook, a loop, or a bunch of coils together. For example a tension spring typically has a loop or a hook, whereas a compression spring typically has coils together as the end, and a torsion spring, or a spiral has two straight wires.

Spring rates

The spring body basically is a spiral, where the spring rate is controlled by the spacing of the coils. Given that we can control the machine, we can change the spacing on the fly resulting in being able to create differing spring rates using the same wire, in the same spring. If the spring spacing is consistent, the spring will have a constant rate of compression, if we slowly change the spring spacing we can generate a spring that changes spring rate when it compresses, and if we put two springs together we can have a dual rate.

Cool springs are coming!

Now let’s make some cool springs. The next one will breakdown the Gcode for making a fairly standard coil spring.

Posted on

LTE connection fun Update 2

So StarLink has a 12month waiting period, and they just had a bunch of satellites burn up in the atmosphere, so I don’t expect my StarLink to ship anytime soon.

The LTE device has come back out of the camper, and runs my laptop, while the rest of the house is running off DSL.

Meanwhile at work, I’m getting a new fiber installed into the premises, How come you can’t come here? I’d even take the evil comcast.

One of the issues with living in the middle of nowhere.

Posted on

LTE connection fun Update

The MikroTik I bought seems to work well, but I’m still seeing 20ms delay rate. It’s about $30/month, but that delay makes it difficult to use Teams in video.

I’ve preordered a Starlink dish, and hopefully that’s better.

In the mean time I’ve move the MikroTik to our camper, where it works very, very well while we are on the road. I just need to add a rotator and a knock down mast somehow that works while we are driving.

Posted on

New LTE connection fun

So I live out in the middle of no where USA, and we have crappy internet service… like DSL is still a viable option here. Fiber, Cable and all of that are passing most of us who live here by, due to stupid regulations, and monopolies providing for the people, but looking for profit.

The part that is really frustrating is they just installed new fiber at the end of my road, and will not bring it down the road for us to use. Here’s looking at you CenturyLink!

I hopes of getting better service for less than the $80/month for 3mbs that CenturyLink is charging me, I’ve purchased an LTE modem made by MikroTik.

It took me 22 days to get it configured, which as an IT “Professional” is total BS.

So in hopes of others having more success than I did, Here’s the keys to getting my device up and running on T-Mobile for about $30/month.

1) Don’t get a contract, get a prepaid hotspot card. In order to do this you will have to drive to a T Mobile store run by T-Mobile, specifically ask for it, and then wait two hours for them to activate a card and hand it to you. You will need to bring your device, in order for them to look at it and say it’s not compatible. You cannot open an account with them, or add onto an existing account.

If you want to save the $10 that they charge you for the card, call the phone number, ask them to activate a line, and mail you a card. Take this card into the store, and say “can you please activate this card.” They will promptly though your card into the trash and issue you a new card, but will not charge you for it.

2) in your MikroTik, login with all of the defaults, and setup your password, and associated LAN settings.

3) reboot your MikroTik.

4) go into Interfaces -> LTE and click on the LTE APN’s button.

5) add an APN for T-Mobile USA, as shown below

Note: This information is hidden by T-Mobile here: https://www.t-mobile.com/support/devices/not-sold-by-t-mobile/byod-t-mobile-data-and-apn-settings

6) Reboot your MikroTek

7) under Interfaces -> lte1, assign the APN to your interface

8) Wait like 10 minutes for T-Mobile to stop being stupid, go have a cup of coffee or something.

9) Rejoice at your less crappy internet connection.

I’m now seeing 3mbs download as well as 3mpbs upload, Quite an improvement over my 0.8mbs upload speed that CenturyLink thinks is acceptable. You may also need the DNS information for T-Mobile, which is located here: https://www.sprint.net/faq/dns

Now I just have to get it up on the pole, but that’s for another day.

Posted on

Raspberry Pi Zero W – Python issues

So I’m working on a quick and dirty Raspberry Pi Zero W based status light, and ran into some issues.

First of all, the version that ships with Raspberian OS light is version 2.7 of python.. that’s old, so let’s fix it.

After logging in I do a:

sudo bash

This is because I’m lazy and don’t want to type it all the time. I’ve been using unix for too long to not have a root account.. bad practice, but I’ve been using it that way since SCO unix was cool.

First thing is to run the update by doing the following:

root@raspberrypi:~# apt update
root@raspberrypi:~# apt list --upgradable
root@raspberrypi:~# apt upgrade

Now make sure Python 3 is installed

root@raspberrypi:~# apt install python3

but after the update, let’s check…

root@raspberrypi:~# python --version
 Python 2.7.16
root@raspberrypi:~# ls -l /usr/bin/python
 lrwxrwxrwx 1 root root 7 Mar 4 2019 /usr/bin/python -> python2

Well… that’s dumb… but looking into it more it looks like /usr/bin/python is just a symbolic link.

root@raspberrypi:~# rm /usr/bin/python
root@raspberrypi:~# ln -s /usr/bin/python3 /usr/bin/python
root@raspberrypi:~# ls -l /usr/bin/python
 lrwxrwxrwx 1 root root 16 Jan 18 07:01 /usr/bin/python -> /usr/bin/python3
root@raspberrypi:~# python --version
 Python 3.7.3

That part is all fixed now…

Posted on

GRBL 3d wire bender, Part 5 : The hardware build

The actual hardware build consists of several parts

  1. The wire spool holder
  2. The wire straighteners
  3. The feeder unit
  4. The rotational axis
  5. Our favorite robot: bender

The wire spool holder

The wire spool holder is dependent on what your wire comes in. If your wire is flat piano wire, you can skip the whole feeder mechanism, and straightening parts. Normally though you buy it in a roll. A typical  304 Stainless Steel Wire comes in a 1/4 lb coil and a 1 lb coil. You can also get it on a spool, but don’t expect that.

The way I’ve dealt with this a 4″ long 1/2″ diameter bolt, with a T nut on one side, and locking nut on the other, mounted vertically. The wire simply drops on.

The wire straighteners

In order to get the bend correct, first the wire has to be straight. The straighteners do this by running the wire though a series of rollers. There is two sets, a vertical and a horizontal set, made of a combination of bolts, bearings and 3d printed parts.

A typical example is shown here, image thanks to HowToMechantronics.com. His files work great, and are available here: https://howtomechatronics.com/projects/arduino-3d-wire-bending-machine/

The Feeder Unit

My feeder unit is based on a MIG feed roller, and a bearing as designed by jiripraus. The instructions are here: https://www.instructables.com/id/Spring-Making-Wire-Bending-Machine/

The Rotational Axis

The rotational axis is based on a photograph rod, and some 3d printed parts. I am relying on https://howtomechatronics.com/projects/arduino-3d-wire-bending-machine/ for these.

The Bender Unit

For now my bender unit is based on Mechatronics version, however I expect this to be reworked quickly. The link is here: https://howtomechatronics.com/projects/arduino-3d-wire-bending-machine/

So now that we have version 1.0 up and running. I’ve got to go program some springs…

Posted on

GRBL 3d wire bender, Part 1 Overview

I’ve been working on a 3d wire bender to make some springs, as I need them to be right, the first time, and every time after that.

First thing I did is look at a bunch of tutorials. So far not a one is perfect, but it’s got enough stuff to make a go at it.

My idea is to set the device as a GCode unit, with the X being the rotation, the Y being the 2nd rotation axis, and the Z being the feed, similar to a Lathe.

Typical Lathe axis

in my case, it’s going to be a bit different as the machine has to look like this.

Image is courtesy of https://howtomechatronics.com/projects/arduino-3d-wire-bending-machine/

The Z axis rotates the bender unit around the wire, and the bender unit puts a crimp in it, which is running on the X axis. This leaves the feeder unit, which is basically a MIG wire welder feeder, but tied to a stepper motor so it can be moved out a specific distance as the Y axis.

The only odd thing is the pin at the end has to be able to push on both sides of the wire, so it has to be able to be raised and lowered on ether side of the existing bend. I’m going to use a servo to do this.

Posted on

Suspension is important

So the rubber in the discovery is 23 years old (happy birthday?) and it’s time to replace most of it. The rubber is old and cracked, sometimes even in half.

I’ve gone out and gotten new urethane bushings, which should help quite a bit. They of course are yellow to match the truck. Installing them turned out to be quite the annoyance, until I found out the trick.

One big giant c clamp. The trick is to take the bushing, add lots of lube (in the form of synthetic axle grease and then stick the first bolt in, barely tight, but enough to grab over the retainer, and then use the c-clamp to the the side of the bushing to crush into the spot. I used the c-clamp on the side where the bushing is split, and then tightened the clamp down until the retainer touched the metal. Then I could tighten the other side.

add in the pile of tools, and the installation becomes easy.

Posted on

Discovery Throttle Body Heat

So normally this is a system that gets thrown away very quickly, but seeing as I’m trying to build a truck that will be ok in cold, I’ll fix it. Underneath the throttle body / intake manifold, is a small plate.

Gems all the way!

It’s labeled #48 on the diagram for the “air flow meter, hotwire and gems EFI” setup. Below is a picture of it in the truck. Really hard to see.

This plate acts as a heat exchanger to warm up the incoming air to prevent ice forming on the throttle body butterfly. Mine was trashed and rusty, and the gasket had dissolved leaving a lovely goop on the manifold.

Yummy! gasket left overs

This was a fairly simple design and below is an example of how it’s supposed to look.

Here’s the part, cleaned up inside, without the gasket.

My gasket is trashed. Let’s make a new one using an old camper tail light.. The aluminum is about the same thickness as the gasket, and it will not galvanically corrode, unlike steel, and it’s not water soluble, like the original paper one.

Let’s make gaskets!

add some tin snips, a hole punch and some time, and we are ready to reinstall.

All better!
Posted on

Out of time and Energy.

My beautiful wife and I just decided to expand our family to three.

The result is that I have had nothing I can post about, because I have just been trying to sleep. My Wifey is even more amazing, in that I have been getting more sleep than her. I am hoping to get back to LandRovers, Crops and other fun stuff soon.

For now, I’m going to go sleep.