I was about to pay for those small neodymium disk magnets...from ebay...I'm thinking of buy 40 although I need 32. but 1 magnet is 4.68 pound = $7.5498.

40 magnets = $301.992~ $302. Damn that's a lot of money to spend only one the magnets! well that's the only place, I will...but if there's a better price elsewhere that would be great!

 

I was about to pay for those small neodymium disk magnets...from ebay...I'm thinking of buy 40 although I need 32. but 1 magnet is 4.68 pound = $7.5498.

40 magnets = $301.992~ $302. Damn that's a lot of money to spend only one the magnets! well that's the only place, I will...but if there's a better price elsewhere that would be great!

£4.68 is for 50 magnets, let's hope you haven't ordered yet because otherwise you have 1600 magnets.

 

£4.68 is for 50 magnets, let's hope you haven't ordered yet because otherwise you have 1600 magnets.

Stupid me!! I saw that '50' but did not pay much attention...

lol I have not ordered yet but I will just now...

thanks!

 

I was checking out some chessboard on the market to work on and found this *wooden board* looking good...

The chessoard itself is very thin...the was no measurement written down so I quickly made quick measurement...

- each square is approximately 3cmx3cm;
- it seats perfectly on a wooden stand of 5 cm high;
- ~3 cm distance between inner square (that has the 64 squares) and outer square;

outer square was ~ 36 cmx36cm and inner one 29cmx29cm

The above were quick measurement...

do you think it worths buy it?? or another size board would be more appropriate?

Sorry if it a stupid question!

Pieces have different heights...maybe they should be customized to the same size of the arm will have to go down to different levels!

Complex project!

Thanks!

 

Here's a thought for the differing heights, the spring probably isn't required:

I don't think you need a servo for this joint, just let gravity do it's thing.

 

Alright! I get the picture now... Thanks Markd77

what about the size of the above chessboad, is it ok?

And as for those metal thumb http://www.discountofficeitems.com/...&ref=adwords&gclid=CKzB6rnNzrICFYWo4Aod5RoAXw

Im correct to say that it $0.55 per box. and the box has 100 of it, huh?

[edited] Also these can be found at local store, right? are they special on something?

 

what about this power supply? http://www.digikey.co.uk/product-detail/en/EPSA120050UE-P5P-EJ/T1147-P5P-ND/2511848

How do you interface this with the circuit? I mean there should be some kind of connector/adapter to the circuit, right? I don't know what's it called...

I need a digikey link for it if possible

thanks!

 

Yes, 55 cents for 100, chess board size is probably OK, smaller would make the arm easier, less distance = less torque. On the other hand it's already smaller than a normal board and bigger looks more impressive.

 

what about this power supply? http://www.digikey.co.uk/product-detail/en/EPSA120050UE-P5P-EJ/T1147-P5P-ND/2511848

How do you interface this with the circuit? I mean there should be some kind of connector/adapter to the circuit, right? I don't know what's it called...

I need a digikey link for it if possible

thanks!

I doubt it's powerful enough if you will be running the 5V servos from it as well, they can use 500mA each as they start turning.
Something like this should be easily enough to supply all 12V power and through regulators to 5V.
http://www.digikey.co.uk/product-detail/en/AWSP60-12/237-1301-ND/1010430
You should install a mains cable and DC cables somewhere that the terminals can't be touched, get someone to check it for safety before use.

 

Ok Thanks...I think I'll get the power supply from local store...

the size of the chessboard looks medium to me...that's why I asked!
BTW, what's the normal size of the chessboard!!

I think it about time I come up with a comple (Eagle) schematics of everything we been discussing (chessboard circuit) as all components that make it have been discussed!

 

Hello,

The wiki states that the squares of the chessboard should be between 50 and 65 mm (2.0 to 2.5 Inch).
http://en.wikipedia.org/wiki/Chessboard

Bertus

 

Hello,

The wiki states that the squares of the chessboard should be between 50 and 65 mm (2.0 to 2.5 Inch).
http://en.wikipedia.org/wiki/Chessboard

Bertus

thanks!

I actually read that but I need more measurement on inner, outer squares, etc...but maybe, as Mark mentioned, that would make things easier given the complexity...

I would be to make a bigger one but for now...this project is a headache given that my electronics skill level is very poor...

 

Attached are the component ordered...Hope I have everything for the board...but I can still place another one if I forgot something...

Index 8 is not for this project!

Magnets have been ordered from ebay

Now ima quickly write a piece of code and do the breadboard for my thread 'sound2'

thanks!

 

This is not my work...just similar work showing how the serial cable and power supply been connected...and I am planning to do the same...

But I am thinking...the chessboard (platform ) i am planning to use (outer square: 36cm*36cm; inner square: 29cm*29cm) seems to be small...
thinking of a bigger one (but not too big)...any suggestion...the above is the bigger I have found so far...maybe I need to look more..

 

The one I saw looks exactly like this one...it a 12 x 12 inch wooden board...

[edited] and this http://www.ebay.com/itm/CLASSIC-WOODEN-CHESS-SET-CASE-BOARD-16-DOUBLE-WEIGHTED-K-3-A37EL-BCT-/221130143873?_trksid=p2045573.m2042&_trkparms=aid%3D111000%26algo%3DREC.CURRENT%26ao%3D1%26asc%3D27%26meid%3D2491818801611248362%26pid%3D100033%26prg%3D1011%26rk%3D1%26sd%3D221130143873%26 has a reasonnable size...

but I will keep looking in local store

 

It might be good to wait for the hall sensors and magnets before ordering the board. If you find the detection area of a sensor is large then bigger squares would be better. There's plenty of other stuff to be getting on with like getting some basic code working for controlling 3 servos from the PC.

 

It might be good to wait for the hall sensors and magnets before ordering the board. If you find the detection area of a sensor is large then bigger squares would be better. There's plenty of other stuff to be getting on with like getting some basic code working for controlling 3 servos from the PC.

Thanks Mark! I think you are right about the board...I should worry about this last! The most *serious* and *important* problem is controlling the arm (servo motors)...

In my attachment of post #60 I showed a scketch with 4 DOFs (4 motors) and you mentioning only 3 motors...my guess is that you think that the motor in joint4 (the one that is connected to the solenoid) is Not necessary as pieces need to be picked up at an angle of 90 degree therefore we can use gravity...

Am I correct? if so this is great as we now only have 3 motors to control!

But the basic code to start with to control these motors should written for the microcontroller...not the PC, right? coz the PC only communicate with the mcu...the protocol goes like this...the electronics chessboard (mcu) send a signal (of its move) to the PC and the PC also send another signal to the mcu (of its counter move)...

But right before that, I think we (actually I...lol) need to identify those 3 motors!!! to be used and their driving circuitry...I mean have its hardware design (I must come up with this in the next 3 days but have an exam on the 8th...Oufff it too hard)...as we did for the chessboard...and I need that for my paper design...or else Im dead.

On the quote highlighted...do you mean if the magnet might be a bit strong and might triggered the one (s) around? hasn't this been taken care of by using schottky diode or something? but I got your point...

thanks!

 

In my attachment of post #60 I showed a scketch with 4 DOFs (4 motors) and you mentioning only 3 motors...my guess is that you think that the motor in joint4 (the one that is connected to the solenoid) is Not necessary as pieces need to be picked up at an angle of 90 degree therefore we can use gravity...

Am I correct? if so this is great as we now only have 3 motors to control!

Yes, the electromagnet is pretty heavy so will stay vertical on it's own.

But the basic code to start with to control these motors should written for the microcontroller...not the PC, right? coz the PC only communicate with the mcu...the protocol goes like this...the electronics chessboard (mcu) send a signal (of its move) to the PC and the PC also send another signal to the mcu (of its counter move)...

There's going to be some code on both obviously, you can either send from the PC a grid position, and lift and drop commands, or send actual servo positions from the PC to the PIC. I think the second method would be easier. They are both possible, but the first method involves triginometery on the PIC which will take a while to code on the PIC.

But right before that, I think we (actually I...lol) need to identify those 3 motors!!! to be used and their driving circuitry.

I think hobby servos should be able to do it, you might be able to get away with a less powerful one than this if the board isn't too big.
http://www.google.co.uk/products/ca...a=X&ei=FuFtUIqhC4aJ0AXf8IHACQ&ved=0CEsQ8wIwAg
The torque on this one should lift nearly 200g at the end of a 50cm arm.
It's also possible to reduce the torque required using counterbalance weights or springs.

Servo control is not too hard:
http://en.wikipedia.org/wiki/Servo_control
For 3 servos if you start the first servo pulse, wait 6.66ms, start the second pulse, etc, this gives you an easy way to get the timings accurate even if the pulses are similar lengths.
I'd use a 16 bit timer interrupt and make sure nothing can mess up the length of the pulses, otherwise the arm will jerk around. You will probably have to turn off other interrupts at critical times.

 

I think hobby servos should be able to do it, you might be able to get away with a less powerful one than this if the board isn't too big.

Do you think that servos will have enough repeatbility to find the pieces and put them back where they should be? Maybe stepper motors could do better.

 

I think it should be fine, the accuracy required isn't massive, the electromagnet should pick up off centre pieces and it doesn't matter that much if they aren't placed exactly at the centre of the square.
This one looks like hobby servos and it's pretty impressive.
http://www.youtube.com/watch?v=zV6EqS9Zrwo