[santiniuk]

Hi all,

After building the picstep boards I am very impressed how well they work on a kitchen table driving steppers

I don't have the machine hardware built yet to really thrash them around but so far so good.

I understand a lot of people won't want the hassle of programming the pic's or may not have a programmer.

If anyone (UK only I'm afraid) would like to have pic's programmed for them just drop me a mail.

I will program them free of charge and return same day. Please specify 4Mhz or 20Mhz code.

I don't expect anything for doing this but do encourage anyone who plans to build the Picstep boards to make a small donation to Alan at :-


http://www.fromorbit.com/projects/picstep/

Cheers

Shaun

[pminmo]

Berin,
I don't know the answer to that one, but suspect you will have to make a symbol and package layout. Cadsoft also has usnet news goups on eagle that you can post this kind of question too, as well as you might look through their downloaded libraries.

Phil

[pminmo]

santiniuk,
Glad to hear the picstep boards are working out. I posted a link to his picstep boards on my website a couple of weeks ago. He really has done a firstclass job.

Phil

[santiniuk]

Thanks Phil. Just itching to start the real construction now !

In the UK the LMD drivers are not cheap and seem hard to get hold off which is a shame. I offered the pic programming help because I know how sometimes this can put you off a project.

Hopefully this might just tempt a few others to join in and have a go building Alan's boards.

Shaun.

[BobLWeiss]

I would be willing to program the PIC's for anyone in the US for free. I just ask that you pay for return shipping so it doesn't cost me anything.

I built the picstep controller myself and using it on my machine. Very impressed with its performance! Nice deisgn by Alan...You could save yourself alot of money if you don't need a controller that supplies more than 3amps.

Bob

[pminmo]

santiniuk,
Yes the LMD drivers are expensive in the US also, $10+ a piece. One of the reasons I opted for the allegro 3977 part, I could live with the 35V and 2.5A. $6 allegro vs $23 for drivers and a pic for the same function. Multiply that times 3 axis and thats $17 x 3 or $51 part differential. I am periodically working on a new version of my 3977 board I hope to make available to people. It uses the slp package which is smaller. I'm working to drive the board cost down more. Hobbiests you know, most of us (me included) are on the skimpy side when it comes to spending our cash.

Phil

p.s. Just got my phone bill yesterday, $60 in international faxes to order my last set of "cheap" boards. Six $6 calls when the board house fax machine answered, but didn't acknowledge a seventh when it acknoledged and received but didn't signal complete (they actually got that one), a seventh before I threw in the towel. Got to be a better way!

[andyew]

Phil, I've been away for quite sometimes, dealing with the mechanical part of my lil cnc milling machine... As i m going for the A3977 direction (since i have em free as samples from Allegro), i need your helping hand for this. I've read from the datasheet saying tat it's recommended to solder A3977 lil legs directly onto the board, to ease the heat dissipation purpose. As i m very new to soldering parts like this delicate, could i use some kind of socket for this 44-pin devil instead???

If this is possible, it'll b much safer for a novice like me to solder the socket without worrying to burn that chip OR solder 2-3 pins at once accidentally! Moreover, it'd b possible too to replace it at ease!

Maybe i would need some kind of EXTRA COOLING if i insist to use socket+chip system?? Hope u could help me with this...

Andy

[pminmo]

Yes it's a quandry. Allegro doesn't recommend sockets, but their on demo board is socketed. A socketed 44plc takes a different board layout. If your not not running the full 2.5A at 35V, I think it would be worth a shot at a socket, then attach a heatsink to the top of the chip with thermally conductive adhesive.

Phil

[andyew]

Actually, i m planning to push to its limit (2.5A @ 35V) since my motor could suck in quite some Amps (PK268 steppers)! So, do u think i could still stay with SOCKET + HEATSINK?

If not, any recommendation or tips on how to solder those tiny lil pins without damaging it? How do u detect if we've "burnt" the internal organs of the chip?? Smoke or smell or colour?

The very first time i saw this chip, i nearly fainted, it's really tiny! (And, i've just found out that the SLP package is less than a quarter of my SED samples!!)

Thanks Phil!
Andy

[pminmo]

PK268 2A @ 4.5V? I solder them with a fine tipped soldering iron, fine solder and a magnifying eyepiece. No way to tell unobvious damage. I suspect that you can use the socket and heatsink ok.

Phil

[BobLWeiss]

I have samples of the 3977 chip in both packages. I was thinking of using a socket as well, if you build it with a socket let me (us) know how hot the chip gets with a heatsink on it please...I am very interested in seeing how it performs socketed. I have a good design for that chip.

Bob

[andyew]

Thanks Phil! Actually i meant for Bipolar Parallel which uses all the 8 wires available, and the current can go up to 4A per phase for this conf. Otherwise, Bipolar Series will be 2A as u said.....

Bob, surely will update here if i did that.... since u have a good design for A3977, care to share it here?? or could u email me for reference as i m going to use the design on Phil's website?? Thanks first!

I also have seen the development kit offered by Allegro itselt, features a socketed A3977 on the board. It claims to go up to max limit, and as seen, without heatsink! But i'll add a heatsink glued to the top of the chip when going for high current...

Thanks every1!

[pminmo]

andyew,
I seriously doubt if the chip will survive 4A per phase.

Phil

[BobLWeiss]

since u have a good design for A3977, care to share it here?? or could u email me for reference as i m going to use the design on Phil's website?? Thanks first

I didn't design it myself but you can get it on Yahoo's group Electronics_101. Its in the file section under Stepper Driver. Its a PDF and comes with an opto-isolated breakout board too. Its all on one board. Nice design and easy to follow.

I am putting it into Eagle now so I can design the boards which I will share here.

Bob

[meeeul]

Hi Guys,

This is a great forum. I learned a lot by reading so far.

I am planning to build the 4 axis interface board and A3977 driver boards using Phil's plans.

Any suggestions ??

Thx
Mehul

[Ito-Brazil]

Start building small machines. I started to build a big one, but all stuffs when got bigger, are more expensive. And the small one will machine the peaces to the big ones.
I don´t know if you understood, sorry my english, hehhe.
START WITH THE SMALL ONES
USE CHEAP PEACES
ALWAYS TRY THE SIMPLICITY
READ< READ AND READ THIS SITE
ASK EVERY TIME, PEOPLE HEARE ARE VERY ACCESSIBLE
Good luck!

[Ito-Brazil]

And of course, always try build by yourself before buy a peace, its fun and it´s not so dificult as you think.
Try to do your PCBs, it´s very fun!
And don´t forget to thank Phil . He is the one! Phill did a great job on that site, really amazing...

[andyew]

I didn't design it myself but you can get it on Yahoo's group Electronics_101. Its in the file section under Stepper Driver. Its a PDF and comes with an opto-isolated breakout board too. Its all on one board. Nice design and easy to follow.

I am putting it into Eagle now so I can design the boards which I will share here.

Bob

Thanks Bob!

[berin]

There are a lot of ways to build a machine, the best suggestion I can give is go for what you think you would need the most! some designs are a lot easyer to build then other are. And small one's are even easyer. Trust me if you get most of your parts from LARGE old printers you can get most every thing you need with out having to shell out a single dime. The easyest design in IMO is a stationary Z with a moving table. It takes only a few lengths of rod, angle iron, a peice of hardwood plywood or MDF, a hand full of brass sleeve barings, 1/4" threaded rod, 1/4" connector nuts solderd to a brass peice for your mounting system, and your off and running for a basic start to building your xy portion of the machine.
Remember small machines are MUCH easyer to start with and you can BUILD parts for larger machines with the small machine. Thats basicly what I'm doing, the only catch is I have an unlimated supply of free parts to me which I sell here on cnc zone. every thing but lead screws.

[meeeul]

Thanks guys for your suggestions.

I am planning to use the stepper motors from old HP Printers. But don't know which driver board will work with those stepper. Does A3977 work work with printer steppers ?

Also I didn't see any single sided copper layout for A3977.

Am I missing something ?

Thx