I have posted a working design without pull ups, why do you want to add them.

BTW: have you received back your components, I posted Monday this week.?

Hi,

They were suggested earlier in the thread, just checking. It's easier to check now, than wait till I've etched the board.

No components received yet.

C.

 

You should always prove a design by building a test circuit before laying down artwork, I have said this in previous posts..

The small package was posted in a Jiffy bag, with 4 first class stamps affixed, into to my local collection box, on Mon 15th Sept, if it does not arrive by Monday next let me know.

 

You should always prove a design by building a test circuit before laying down artwork, I have said this in previous posts..

The small package was posted in a Jiffy bag, with 4 first class stamps affixed, into to my local collection box, on Mon 15th Sept, if it does not arrive by Monday next let me know.

Hi Eric,

Ok about the package.

When you suggested that I should build a test circuit, I replied, that I don't know how to build one without a circuit board to solder the little SM Mosfets to. I'm open to suggestions. I haven't etched a circuit for years, so a test build of a circuit won't hurt, and can be seen as practice.

C

 

You can purchase mini 'adaptor' pcbs for SMD.

http://www.bitsbox.co.uk/index.php?main_page=product_info&cPath=255_313&products_id=2120

 

You can purchase mini 'adaptor' pcbs for SMD.

http://www.bitsbox.co.uk/index.php?main_page=product_info&cPath=255_313&products_id=2120

They're a good idea, thanks.

 

You should always prove a design by building a test circuit before laying down artwork, I have said this in previous posts..

The small package was posted in a Jiffy bag, with 4 first class stamps affixed, into to my local collection box, on Mon 15th Sept, if it does not arrive by Monday next let me know.

Tuesday: No package yet!

 

OK,
Normally I post at the Post Office, this time it was such small package I used a post box.!
I will try to trace it via the PO.
In case I have no success, please add the total value, let me know and I will send you a cheque.

It appears even the UK Post Office can no longer be trusted.!

Eric

 

OK,
Normally I post at the Post Office, this time it was such small package I used a post box.!
I will try to trace it via the PO.
In case I have no success, please add the total value, let me know and I will send you a cheque.

It appears even the UK Post Office can no longer be trusted.!

Eric

Hi Eric,

Bring back the pigeons There is absolutely no need for a cheque, (or another stamp for the PO). Give it 6 months, and it will probably turn up!

Cheers, C.

 

Here's the latest Schematic of the 18F2431 H-Bridge with QEI and PWM.

Are all of the connection ok?

C

 

hi,
Looks OK, what are the two ADC inputs for? RA0, & 1
A power ON led for the 12V would be useful.

When you do the PCB artwork ensure that the PIC and HB power rails are only connected together close to the large battery connector.
Post your PCB layout when ready.

E

 

hi,
Looks OK, what are the two ADC inputs for? RA0, & 1
A power ON led for the 12V would be useful.

When you do the PCB artwork ensure that the PIC and HB power rails are only connected together close to the large battery connector.
Post your PCB layout when ready.

E

I thought the added ADC pots could be used for tests, similar to the 'pot to PWM' program you sent.

I'll add an 'ON' led, or perhaps the led already on the circuit could flash at switch on?

Because of problems in the past of battery voltage drop as motors switch on, I chose to have a small circuit battery and a large motor one, only connected by the GND.

I'll post the PCB layout.

C

 

Hi,

On the motor drive circuit 18F2431, there are connections AVSS and VSS also AVDD and VDD. I have added pots to the circuit for testing only, so they are not really needed. In this case how do I connect the power tracks?

C.

 

hi,
The ADC test pot levels are not critical, I would link the AVSS/VSS and AVDD/VDD as drawn on the diagram , ie: close to the PIC pins
E

 

hi,
Looks OK, what are the two ADC inputs for? RA0, & 1
A power ON led for the 12V would be useful.

When you do the PCB artwork ensure that the PIC and HB power rails are only connected together close to the large battery connector.
Post your PCB layout when ready.

E

Here is the board layout. I have removed the Pots, and changed some capacitors. I would appreciate a component check please.

C

 

hi,
I am assuming this PCB is double sided.?
It appears all the 'p's on the track are not connected.? do you intend using wire links in all these pad holes.??

E

The FET Gates are shorted to the Source pads.

 

hi,
I am assuming this PCB is double sided.?
It appears all the 'p's on the track are not connected.? do you intend using wire links in all these pad holes.??

E

The FET Gates are shorted to the Source pads.

Hi Eric,

Yes, the PCB is double sided.

Yes, the pads will be connected by links, enabling easy exchange of 'popped' mosfets. Instead of the adaptors that you posted.

Eagled eyed The shorting was well spotted! I will monitor this, but I am pretty sure the shorts don't appear on the SVG when making the circuit.

C.

 

hi,
As the FET;s are on their own pad areas, I dont see any purpose in not using copper tracks to link the 'p's ???
How will copper links make changing a faulty FET easier.

Repost your modified PCB layout when the shorts are removed.

E

 

hi,

How will copper links make changing a faulty FET easier.


E

Hi,

I can remove the links, cut out the section of circuit board, and add a new spare section complete with new mosfet. In previous circuits I found it difficult desoldering and re-soldering in new mosfets to a complete circuit.

C

 

hi,,
The layout is per the circuit diagram, but the general layout is poor. [sorry, but you did ask.]
I would not connect the 0V for the 5V supply at that point in the track, marked with an arrow.
Move that junction closer to the 12V, 0V line.

E

 

hi,,
The layout is per the circuit diagram, but the general layout is poor. [sorry, but you did ask.]
I would not connect the 0V for the 5V supply at that point in the track, marked with an arrow.
Move that junction closer to the 12V, 0V line.

E

Hi Eric,

I did ask

Here's another try: Keep an eye out for my mistakes

C