Member postings for jaCK Hobson

Jeweler's saw? Depends how wide the plate is.

Is the intention just to learn about low level control of steppers, or is it to achieve practical applications of steppers?

If you are really after the latter, then I would suggest getting a stepper motor driver board and use the arduino as a controller for the board. All the arduino has to do is pulse a pin for each step, and set another pin for direction. I want to get this: https://learn.adafruit.com/adafruit-motor-shield-v2-for-arduino/overview. I have an earlyer version.

If you are worried about how to do multiple things at once on the arduino then again, go for the separate controller.

The arduino UNO pretty much just does one thing at a time, so if you need to do two things then you have to keep switching between them. This can get wasteful in available processing power if you constantly have to check if something needs doing. The UNO does provide you with 2 external interrupts which you can attach code that gets called only when the interrupt occurs.

I haven't see any great tutorials on how to design your code to do many things at once. You could read this thread: http://forum.arduino.cc/index.php?topic=41460.0 (i.e. search for multi-tasking or multi-threaded)

I think my clock project has bought a dose of reality to me.

The Arduino environment is hugely more accessible than any similar thing I've used in the past but....

20 years ago I was very comfortable programming in C - it was my day job. Last weekend I spent Sat getting a GSM module to phone home - the on-line examples didn't work out the box for me. I spent Sun getting time from the GPS module - the TinyGPS library didn't quite work out the box and it wasn't friendly for debugging so I wrote the time parsing code from scratch (a trivial achievement for a C programmer but took me all day). I suspect my previous programming experience really, really helped.

I can imagine that someone with no previous programming experience could struggle with any significant project. I would still recommend anyone to get a starter kit and run through the tutorials... but doing a lot of custom code could require a steep learning curve.

If you object to different brackets and don't know how to implement multi-dimension arrays in your favourite language (Perl, python included) then be prepared for some hard work.

For the original poster, this thread on another forum seems to answer the question quite well:

http://www.britishblades.com/forums/showthread.php?126992-10m-Air-Pistol-Turning-Target-Project&highlight=arduino

On another topic, I got into fiddling with old clocks a little while ago with the idea I might make my own.

I completed my first prototype clock today - not quite the mechanical engineering project I imagined but it is probably far more accurate. Only works outside where you can get a GPS signal though:

(all cheap non-official-arduino components)

Edited By jaCK Hobson on 16/11/2014 13:35:19

FYI, I bought this: http://www.amazon.co.uk/gp/product/B00FPEC4Z0?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s01 and am very happy with it as £36.

It is a clone, so contrary to IanT's good advice. To buy something like this from Maplin seemed to cost £80+ and I just felt like taking a punt... which seems to have paid off. Everything seems to work. The stepper is a bit stiff in one direction. There is no documentation delivered with the kit but you should find that you can complete many of the on-line tutorials with the components available in this kit. It seems to be supplied and supported in the UK and the contact is very quick to respond.

If you can afford to spend more and want to maximise the chance of having the easiest introduction then take IanT's advice. Get a starter kit from Maplin which comes with documentation and bits for the tutorials.

If going down the route of steppers, then I chose to start with a dedicated shield. There are lots so which one? I bought an Adafruit v1 compatible board http://www.amazon.co.uk/SainSmart-L293D-Shield-Arduino-Duemilanove/dp/B0081JPBA6/ref=pd_sim_sbs_ce_2?ie=UTF8&refRID=0AM9F9JCQ8NHHRVV20ZB BUT I intended to get the v2 which seem to be much better. So my advice, not based on experience, would be to start with Adafruit v2 stepper shield - I'm not sure where to get it from as the original AdaFruit requires you to get out your soldering iron.

A misunderstanding. I can't remember feeling disagreement with any of your writings.

I guess my motivation was to encourage people to try Arduino, even if they tried and gave up on PICs. I'm talking purely for a dabbling beginner doing one off projects.

Edited By jaCK Hobson on 11/11/2014 07:57:23

Edited By jaCK Hobson on 11/11/2014 07:58:08

I 'played' with PICs, The Arduino environment is just much easier and quicker to develop in. If you already know PICs and assembler, have favourite libraries of code etc then maybe stick with them. If you are coming new and want to dabble then Arduino is much more accessible than PIC.

It all just works. You can get the whole thing running and blitz through 10 tutorials in a morning. If you don't know any programming, C is easier to tweak than assembler. Lots of shields have serial interfaces and C makes processing serial data much more simple than assembler. I would guess that after a day or less of tutorials you could feel confident you could get a 16x2 LCD shield displaying selected output from a GPS shield (e.g. to create a super accurate clock) as an easy project completed within an hour (and you would probably feel confident you could tweak the clock to trigger an annual event with micro-second precision).

You don't get code bloat on the board - the whole running program is refreshed with every download. (You may get bloat on your computer... but so far my experience is that libraries available on the web tend to follow library management best practice which leaves your computer in an easy to manage condition).

If you just want to coordinate control of multiple real-world things without a lot of manual input then Arduino is a great place to start looking.

If you think you need a keyboard and/or a sophisticated graphical display then start with the Pi.

It you want to have input, display, and all sorts of sensors in the smallest packaging... then it is difficult to beat a 'smartphone' with Android.

But for the original poster's requirement... I'd vote off the shelf timer relays and limit switches.

Inspired by this thread, I've taken a dive.

As the Aduino is open source it is a good opportunity for 'cheap chinese knock-offs'. You can get a UNO compatible board and a huge amount of experimental bits for not much more than the price of a single UNO from Maplins. I got a pack from 'Sinton' via Amazon Prime next day delivery. Comes with stepper controller, stepper, and servo so great for dipping your toe (although probably not appropriate for our typical machine tool control). And I can confirm the board works in as much as you can control flashing lights on it.

[Sintron] UNO R3 Upgrade Kit with Motor LCD Servo Module for Arduino AVR Starter

(deleted, wrong thread)

Edited By jaCK Hobson on 02/11/2014 09:51:25

VHT - it just works! http://www.frost.co.uk/vht-black-wrinkle-finish-310ml.html

Used it a few times e.g my previous old favorite tool (still get excited looking at this pic):

Edited By jaCK Hobson on 21/10/2014 23:29:05

Good reading. Hadn't seen that before. Thanks

It's a Boley. I guess pre-ww2. A good bit of backlash left to right which I can't adjust but otherwise everything is tight.

Niether does it justice. It is much better as a favorite tool than a jig borer as I can sit with it on my lap while watching telly. The dog is jealous.

Favourite tends to be whatever I last bought.

Black wrinkle paint helps.

Edited By jaCK Hobson on 19/10/2014 22:47:29

Those carbide spade drills would be handy - if a bit expensive.

The runout on the Clarke and the chuck can be too much for small drills. I bought a new chuck and then I bought a Proxxon TBM 220 - I still had trouble.
Make sure the work is held firmly during the drilling, and cannot rock. You need sharp drills, and often 'new' drills are not sharp - particularly cheap small ones. Small drills are easy to sharpen. My new 'secret' is to use a coarser diamond stone (like blue DMT) so you can sharpen a flute with a single stroke. Also, just grind the surface flat, don't worry about the flair you would put on a lager drill. If your flutes get uneven, square off the end to 'start again'. On drills less than 1mm you can still sharpen in a single swipe.
Put most of the drill in the chuck and only leave a few mm sticking out. When drilling, make sure the drill keeps cutting by watching the swarf. Sharpen early. If swarf doesn't show because the drill is badly sharpened, then you are work-hardening the bottom.
Picking up centre with a graver is only easy after you can do it. Use eyeglass to guess the very centre and put the graver there - if it makes a small spot then that may be enough. Another watchmaker's tip is to hold the drill in a pin vice, support the wrong end of the pin vice by the tailstock centre, and feed the drill by hand holding the pin vice.

Heating and quenching in heat-treating salts is a way of minimising scale. On a small scale you could try heating in Lo Salt from the supermarket (try on scrap part first). You will need a decent heat source to get the salts hot enough. Be careful.

Low temp (quenching) salts are not so easy to get. Hot blueing salts may do the job. Maybe a normal oil or water quench won't leave too much scale anyway.

In the past I have been advised to put the part in a small container with the end packed with clay. Heat the lot up in a suitable furnace/forge and put the container clay first into the quenchant. The clay should fall out the bottom, and the part with it. This is probably more efficient at minimising decarb rather than scale and for smaller parts that would fit in a tube. So probably not right for you.

I've never tried any of those. I have some fancy anti-scale mixture imported from US which is better than nothing but not perfect for large parts.

I think so. But my information cannot always be trusted e.g it isn't googleplay, it was google checkout which stopped at end of last year.

I believe this is true for Arc Euro, but https: URL does not guarantee that your details will be secure for other sites.

If you see https in the browser address bar then this suggests that the information was sent securely from the site (e.g. ArcEuro) to your browser.

However, the more important part is that your details are sent securely to the Site from your browser. The URL that controls that is usually 'hidden'. It can be checked (view page source, search for 'action=' and check that the stuff after it starts with 'https:" rather than "http:" but needs basic understanding.

e.g. this is the important part when submitting your username and password to Arc Euro:

<form name="aspnetForm" method="post" action="https://www.arceurotrade.co.uk/retail/registration/login.aspx?ReturnUrl=%2fretail%2fcheckout%2fdefault.aspx" onkeypress="javascript:return WebForm_FireDefaultButton(event, 'ctl00_PrimaryContentPlaceHolder_Login'" id="aspnetForm">

I check every now and then on new sites I buy from. I prefer paypal or googlepay. I also hope my card issuer will help if my card details are used fraudulently. So I don't mean to scaremonger... I just don't want people to think https in the url means the 'site' is safe.

I am completely happy to pay by debit card for Arc Euro purchases.

I've been in the same dilemma for a couple of years (so far solved by spending the available cash on other tools).

AC TIG is a complicated machine. If you want UK support in case it goes wrong then it is going to cost £1000: http://www.weldequip.com/tecarc-206i-acdc.htm Half that cost if you take a gamble on a new machine from ebay. If cost isn't an issue then I'd have go straight for TIG

If someone has not done welding before then I would recommend a £50 (cheapest you can find) starter 'stick' set and try welding some mild steel. I've had mine for 8 years and it performs a useful function. It is a good learning tool as more expensive sets are much easier to use. Treat the £50 as a lesson rather than capital expense.

I only started using a jewlers saw last few years and now I use it a lot. Greatly underrated.