Member postings for An Other

Hi, Duncan

Are you sure you have the 'wrong' boards. The following was copied from the official Arduino site: - note the last two lines - you may have the wrong voltage. Elsewhere I found a comment that the Arduino Mini has been 'retired'

The Arduino Pro Mini is a microcontroller board based on the ATmega328.
It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, an on-board resonator, a reset button, and holes for mounting pin headers. A six pin header can be connected to an FTDI cable or Sparkfun breakout board to provide USB power and communication to the board.
The Arduino Pro Mini is intended for semi-permanent installation in objects or exhibitions. The board comes without pre-mounted headers, allowing the use of various types of connectors or direct soldering of wires.

The pin layout is compatible with the Arduino Mini.
There are two version of the Pro Mini. One runs at 3.3V and 8 MHz, the other at 5V and 16 MHz.

Regards

Don't know if I'm reading this correctly, but according to the manual, multifunctional Input 1 (P58) apparently must be set to 20 to enable multifunction inputs P50 to 55, but by default it is set to 0.

Sorry to resurrect this thread, but I thought this may be useful - I found the following on Youtube, (Link at end of post) - I have three of these Chinese-made units, running a woodturning lathe (1.5HP), a mini-lathe and an SX2 Mill, (both 3/4 HP) all converted to 3-phase, with belt drive operation.

They all worked out of the box, and I have had no problems with them. They seem to be well-made, and certainly do the job. Mine are all 2.2kW rating, all connected in Delta. I have not seen any problems, or overheating. They are fitted with small cooling fans, which operate only when switched to 'Run'. (I also have a German-made Moeller unit rated for 1.1 kW, which has no fan, and gets quite warm after extended use).

The only problem was that the supplied documentation was 'minimal' to say the least, so I ended up Youtubing to find some useful data. (I wanted to use a pendant with two of them).

The units I have are marketed under the name 'Topshak' - there seem to be others, but it is the same inverter - it also comes in different output ratings. (I have no connection with the manufacturers).

Link

Agree with Peter Greene above. I use Thunderbird on three different machines, all using POP because I sometimes want to access my mail offline. I have three accounts in use, and they are not deleted from the server.

We live in Eastern Europe, and when we first came here (about 12 years ago, the service provide by the (state) ISP was lousy - very very slow, and prone to fail frequently - Friday evening was always a good time, then it would come back on Monday morning when the local engineer(?) came back on duty.

Eventually we got a mobile phone, but at that time, it could not be used as a hotspot, although later it was possible. About 5 years ago, by chance, we became friendly with the girl in the local mobile providers shop - she spoke good English, which helped. She mentioned that they could provide up to 50 GBytes/month of broadband data connection free using a fixed router using the SIM fitted in the mobile phones, but many of her customers had complained that it didn't work, and had returned their routers - she had a big pile of them. I asked if I could try one, so she gave me half-a dozen to test after she talked to her manager.

I took them home, plugged in my SIM, and sure enough, it didn't work - then after a bit of checking, I found out that the SIM was retained in its socket by a metal strap - you had to slide the SIM under the strap - but it was so very easy to slide it in so it went over the strap (and very difficult to actually see) - so no connection. All the routers I had been loaned worked when I made sure that the SIM was correctly installed, and eventually I found about 3 truly dud routers from around 50. I got a free SIM for a year as a result as a thankyou from the manager.

Three months ago, the mobile provider (it also provides service in Western Europe and the UK), bought out the state Telecom concern, and now operates that as well - and its service is vastly better than it used to be.

I have no idea what the moral of this story is (was), but it worked for me.

Not sure if this is in the right place, but it might provide some helpful data - clocks, motor feedback systems, Arduino programming, gear-cutting and more. If its wrong, I'm sure a moderator will remove it.

Lots of stuff in the various links scattered around on the site.

Link

Hallo, SoD (Dave),

Re the membrane type switch. I have had problems with these in the past - On at least two of them, the top plastic layer apparently became hard and brittle over time, and eventually cracked. One of them was on a heating controller system - at the time I suspected that it was due to the temperature of the room it was in cycling hot and cold (the boiler was also in this room, hence the temperature variations).

However, I later used another one on a borehole pump control system - this was mounted on a box outside - and the same thing happened - in each case it took about a year to fail - the top surface where you press them cracked and flaked away. As I result, I don't trust them any longer, and prefer discrete switches. Of course, this is a pain when I need numerical entry, so I usually end up with an 'Up' button and a 'Down' button which cycle through displayed values, and a third button to initiate whatever action I need.

Some day I might get around to playing with using the proximity sensing capability of the Arduino inputs.

Interesting links, John,

I did use a DRV8825 - perhaps I should change that. I did start with an A4988, but the motor took rather more current than it liked so I changed to the DRV8825 - these links show that was a backward step.

I'm not in a position to challenge the results in the link, however I still think that the effects of microstepping are dependant on the application. As I tried to explain earlier, I originally wanted a device which would rotate small objects a specified distance to allow regular drilling (wheel hubs and rims in my case). This does not require a rotation of more than 360 degrees (although it will rotate continuously if required - see my first post).

This means that it is rotating under virtually no load (except for the weight of the chuck) between between programmed halts. As your links appear to indicate, mis-stepping is apparent in all modes. Although I didn't consider this when I built it - I simply used 1/16 mode because I believed that multiple smaller steps would give me finer control. From the figures I noted earlier, I should get 3200 steps per rev, so a step of 1 degree should have 3200/360 = 8.8 steps. In practise, this works fine for me - the thing rotates sufficiently accurately for my purposes, and is locked by a separate brake when it stops, to counter pressure on the workpiece.

For me, its a question of building what sufficed to do the job. Practise has shown me that a purely mechanical dividing head was 'overkill' for what I needed, as would be a closed loop servo system, when this simple device does the job - and other people in this thread seem to have the same experience.

However, you make a good point, so designers should take this into account depending on the functionality required. When time permits, I will try to check its accuracy - the articles you have linked to make me wonder about the accuracy of some of the things produced on 3D printers and routers.

Hi, John,

You may have just wrecked the whole 3D router/printing industry!

I have a small 3D Router, and a 3D printer, the controllers of both of them are fixed at 1/16 steps. Of course, accuracy is probably not so 'vital' in these machines, but there are certainly no perceptible measurable or cumulative errors, and I have machined small metal parts on the router.

Given that 1/16 step mode on a 200 step motor produces 3200 steps per rev, then dare I say that single steps never happen in practise. I would guess perhaps that some 'averaging' takes place, but I don't know. I do know that for the indexer I built, I don't need steps of 0.1125 degrees (360/3200) which is what I (should) get with 1/16 steps - its more like steps of multiple degrees - maybe a few hundred steps (perhaps I should have used 1/2 or 1/4 steps). My main need was to make regular steps without having to faff about with index wheels and so on. That said, I haven't been able to detect any measurable errors with my indexer - Perhaps I am wrong, but I would expect this type of microstep error to be cumulative (slipping, perhaps?), but it certainly doesn't seem to be doing that.

I would appreciate your ideas on this - meantime I intend to see what happens with different stepping modes - these will introduce their own errors, because as each step becomes larger, so calculating the number of steps for a given number of degrees will inevitably lead to rounding - bigger steps, bigger rounding errors. This was why I used 1/16 steps in the first instance (I explained that I rounded the number of steps/degree in the software in an earlier post).

The only way I can see round these problems is to use some form of gearing - but I consider that a backward step.

Hi, DutchDan,

Sorry about the delay, the thread dropped off the bottom of the list, and I only just found it.

I got my brake from a company in Germany: (full URL in case you have problems)

**LINK**

This is the one I used:

DC Electromagnetic Brake 24V 2.0Nm(283oz.in) for Nema 23 & 24 Stepper Motor

I think its the first one on the page link above.

This is the 'Brake' page, but they do all sort of stepper and servo related stuff (look under 'Products'. I'm sorry, I don't know what the cost to UK will be - I live in Eastern Europe, and delivery was in a couple of days by DHL from Germany.

I mentioned in an earlier post that I used 1/16 step mode, which reduces the holding torque to about 70%. Its worth noting that the step size is very small in this mode (3200 steps per rev with a 1.8 degree motor). If you can live with less (bigger) steps, then you could possibly use say 1/4 step mode, giving 800 steps/rev, and the holding torque would be around 90+%, or even 1/2 Step mode, giving 400 steps/rev. This may avoid the need for the brake - I guess it depends on what you want to use it for.

I also used a NEMA23 motor - a bigger motor frame would have a higher holding torque - I didn't need the size.

Good luck with it (I keep thinking of different things I could do with it just by modifying the software - but so little time)

Sorry - the site software has changed my URL to a "Link" - if you have problems, send a PM.

Edited By An Other on 16/02/2022 18:39:35

Hi, DutchDan,

Like you, when I first built it, my thinking was that the holding torque of the motor would be sufficient, so my first version didn't have the brake. However, on a couple of occasions, it did move - at the time I was making a tiny countersink to the hole. It wasn't backlash - it actually moved a (part?) step apparently. Eventually I put this down to the fact that I was using the driver in 1/16 step mode, which I found does reduce the holding torque (to about 70% as far as I can find out). , and I think possibly that as I fed the countersink in, it was just enough to move it. (but I'm not sure how!)

I also wanted to be able to leave work in the chuck, but with power off, so eventually the brake was tis easiest solution. The one I used is a 24v DC version, intended for use with a NEMA23 motor. Same diameter as the motor, and about 2cms thick overall. It only uses about 250mA to pull it off, so it was easy to switch it using a small power MOSFET driven by one of the Nano pins, and it locks the shaft solid - no worries! It is 'failsafe', in that it has to be powered to remove the brake.

I actually found the mechanics simple and cheap - the most difficult problem was the switching - I wanted to keep it simple, and used a film-type keypad to begin with, which quickly gave up the ghost. A small mechanical keypad was next, but I didn't like that next to the mill with flying swarf, so eventually I used 3 pushbuttons on the controller box - 2 buttons cycle 'up/down' through numbers/menus on the display, and the third starts/stops operations - seems to work for me.

For the size of the work I use it for, there is enough torque to also turn the work against a small (3mm max) milling cutter - I guess you could use full-step operation for more torque, but less accuracy.

Tony - there is no worm/wormwheel on my indexer - the chuck is driven directly by the stepper, with the brake screwed to the front of the stepper and acting on the same shaft. The stepper has 200 full steps/rev, but is run in 1/16 step mode, so has 3200 steps per rev. This is a step size of 0.1125 degrees/step, which is much smaller than I needed. Of course, it means there is not always a full step count for some rotation angles, but I rounded up or down in the calculation to get to the nearest whole number of steps, implying a maximum error of half a step, or 0.05625 degrees - close enough for me. Of course, if you need additional torque to turn a bigger chuck, then you could use gearing, but I didn't want or need the additional complexity, and it would also allow use of full or 1/2 stepping for more torque (or just use a bigger stepper)

I built a stepper motor indexer about 2 years ago, not knowing about the unit(s) mentioned here. Mine uses an Arduino Nano as controller, with a NEMA 23 stepper motor drive through a DRV8825 'stepstick', a small three-jaw chuck and a magnetic brake to lock it in place after each step.

I built it originally because I wanted to drill regularly-spaced holes around aluminium rims for model cars. I had been doing this in the lathe, but found it quite difficult due to the small rim sizes in a large chuck. After some experiments, the brake was fitted to ensure that the chuck would not turn (as it did sufficiently to break drills of sub-millimetre size). I mount the indexer on a small gantry-type CNC router, which is used to actually drill the holes. This would also give me the option to program the router in conjunction with the indexer stepper to do the whole job automatically, but so far I haven't got around to that.

The indexer uses a 4*20 character LCD display, with 3 pushbuttons to enter values and for operation. The indexer can be set up to rotate in defined steps in either direction at specified speeds, just by pressing a single button. (I did play with an 'auto-run' mode, making the step automatically at specified time intervals, but scrubbed it because it was very easy to 'miss' as step (me, not the indexer).

It can also be set to rotate in either direction continuously at specified speeds - I use it for coil winding.

The software is not complicated, and there is room in the memory for other functions to be included, but I have found the 4-line LCD display to be a bit limiting. I keep thinking about updating it to use an ESP32, and possibly a TFT display to show more information, (and colour!) because this would allow other functions as well. The ESP 32 has more memory, and can also be connected via Wi-Fi (built-in) which would allow control over a smartphone or tablet, but this is something for the future - the thing does it for me for the moment.

I installed it a couple of weeks ago when it was still not a formal release, then updated when Mint released it - no problems at all in either case.

What sort of problems are you getting?

Have I misunderstood something - it seems long narrow strips of steel, undistorted, are needed. I had a 1 x 1 metre piece of 1mm thick stainless steel cut into 5mm wide strips by taking it to a local machine shop, where they stuck it through a large (2metre wide) guillotine for the cost of a couple of beers. Admittedly not a recurring requirement for me (I still have about half the strips), but the relative cost was negligible, so a repeat order wouldn't have been a problem.

The guillotine blade had a slight 'tilt' from one side to the other, so it had a (very slight) shearing action, and as a result the strips came off with a slight 'twist', which was simply to rectify - after this was done (by hand), the strips to all intents and purposes were undistorted.

The width was catered for by a 'stop' system on the guillotine.

I don't know if this would work with plastic material - possibly it would break.

Why should using a piece of appropriate sized hot-rolled bar have less metal in contact with the underside of the slot be, or a bigger risk of damaging the slot? - nothing to stop using a piece of thick steel strip the same width as the slot, and as long as you like, which would spread any load.

If a piece narrower than the slot is used, then yes, it would increase the risk, but I don' think anyone is suggesting that.

Hi, Philip,

I converted my mill (Seig X2 type) to belt drive long ago, without using a kit. I recently upgraded it to use a 3-phase motor, with the same belt drive. I posted some pics of this conversion on this forum on which you can see the conversion, but it is not very clear.

It is a simple mod to do - basically remove the cast iron plate on the top of the mill - the drive gears are under this. I replaced this iron plate with a 6mm aluminium plate which carried the motor, and bought and modified two toothed pulleys to fit the head input shaft and the motor, and connected them with a short toothed belt. The motor mounting plate is remounted in place of the old cast iron plate using 6 aluminium spacers - this has been worked hard now for at least 15 years, and I haven't broken a drive belt yet. I made a new motor mounting plate because I needed to move the motor back a few millimetres to make the belt a good fit - there is room to do that. This mod also keeps the mechanical two-speed system on these lathes - some belts mods eliminate it. (and a 3-phase motor with VfD eliminates the need for it completely)

I'm sorry I am travelling away from home over Christmas/New Year, but if you are interested, I could run up a few sketches to make it clearer when I get back - the belt/pulleys were only a few Euros when I did it (20 Euro?), and a days work to make the ally plate and fit it.

Its a big improvement - most of the noise stops (caused by the gears), and the 'feel' of the mill is much better - more stable - I don't know how else I can describe it. Fitting the 3-phase motor (at a later date) was another good move - it is only a 1/2 HP motor, but is much smoother and more powerful than the old DC thing, and it removes the chance of unreliable controller board failure and 'death of motor' these mills suffer from. (spares are v. expensive!)

BTW - this mod is reversible - if you don't like it, or something go wrong, you still have the original parts to revert to standard.

Edited By An Other on 24/12/2021 11:57:36

If you only need some temporary holding, there was a thread here which dealt with using 'carriage' bolts - get some M6 Bolts, flatten the sides of the head so it fits the slot, and you're done.

Good question, Mike - I'm half-way through fitting DROs to my mill, after doing a 3-phase motor conversion. I think I got enough 'brain-training' working out how to fit the DROs in the restricted space , and next I'm going to use the brain to make something, instead of cutting odd lumps off the material because of the backlash in the machine..

Seriously, though, its clear that eventually hobbyists embrace new technologies over time (even using mills), so its probably inevitable that DROs will become 'standard'. I would think any application of the brain will exercise it, so its just a question of what you want to think about (I think).

Nigel B: - Well, it doesn't look like you're going to be a convert any time soon!. It doesn't really seem to me that you have had many problems with Linux from what you have said. If you can get a first generation PI up and running, then using Linux should be a breeze, with a little application, but if you're happy with Windows and Android, then fine.

I'm sorry I can't agree with you about Google - its true they provide their software free, and this has given them massive data-scraping capabilities. If you care to look for it, there is plenty of stuff in all the media about how Google have used this to force out potential competition, and sold the data on to other companies. I'm afraid I don't have such a rosy view of having my privacy invaded by companies such as this. Also consider what would happen if Google does suddenly decide to charge for their software - it may never happen, but I wouldn't bet on it, and suddenly the world is indebted to one company - and this has happened in other fields.

I agree that some of their software is good - it should be, given their size - and you rightly say Translate is amazing - but where is the competition? - all other online translation services I can find use Googles Translate engine. Monopolies don't have a good record in the long term, so I would prefer to have a choice - which you don't have with Android.

Nonetheless - have fun with it.

Nigel B. I guess we all have different experiences - and I think I perhaps used the term 'paying public' in error. I was a bit concerned to read:

Getting access to data (loss of privacy) with widepread adoption was Google's aim all along !

Its obvious you are right, as the behaviour of Google has shown, but do you have no concerns about that? - this alone would be enough to stop me using any Google product (which is the case for me, unless by accident).

I made my comments after trying to work with Android for some time - as an ex-programmer, I really became fed up with the foibles of Android, given the power of the modern phones Android runs on. I have also made the comparison between a very early (usable) Android, and the version that was on my Xiaomi, which eventually made me dump it. I really believe that it could be made much simpler and easier, but I also believe that the industrial and technical power of Google has forced Android to the forefront. Perhaps a little like the way Bill Gates modified CPM then managed to get IBM to use it in the early PCs. In general, there is no alternative, so people tolerate it because they don't know of alternatives.

I think this leads in to your comment about frustrations with various versions of Windows. I think this is quite a common complaint, and I for one could never understand why people paid (until recently) for a product which has long been defective (tell me all the security updates and patches that MS has pushed out over the years are not defects!).

Although there are many alternatives to Windows, probably the main one is Linux. I came to Linux years ago as an ex-Unix user, and I agree totally that Linux in its early years seemed to be intended strictly for a narrow circle of experienced users - it certainly wasn't easy even to install. But that has changed - I would say the major Linux distros are not difficult to install. (A recent attempt at Windows 10 took me several hours, and wasn't entirely successful, on a new machine, but a Linux Mint or Ubuntu install usually takes less than an hour.

Linux isn't flawless - its a developing tool (and now unfortunately Big Tech is getting its claws into it, so it will be monetised and crippled, IMO), so sometime things go wrong. That said, there is a huge community online which will help. As a Linux user, it seems to me that most people, once converted to Linux, stay with it. There are several threads in this forum dealing with 'Windows Problems', but I can't find many dealing with Linux Problems. Maybe you should give it another try, and report your experiences on this forum, and maybe this can be laid to rest - I for one would like to know what difficulties you have - then perhaps there will be another tool people can use. You do say you have 'limited' experience with it. As for me, using Windows these days is a crippling experience, and I don't have that much time these days to waste.

BTW, I agree with what you say about Xiaomi's expansion, and the sheer number of things they now seem to make - as I said before, my problem is not the hardware, its Android.