PICAXE serial output into UCL2003a

I am going to use a AXE-117 14M2 PCB to try a stepper project. I saw a mention in one of the posts that one should put a jumper between the 14M2 serial output (pin 13) and the Pin 2 of the UCL2003A IC. I am not going to use Pin 2 of the UCL2003A so can I cut the pcb track between the two.

Thanks

If you are not going to use it you don't need to do anything.

The only issue would be if you are trying to use output0 for driving the stepper - as it is shared with the serial download pin this could make the stepper do strange things during downloading of a new PICAXE program.
But if you are not using output 0 anyway it doesn't matter.

Thankyou for that. The other thing that was I thought starnge, the AXE-117 has no track for UCL2003A pin 16?

Never mind, just need to explore some code just to show me the board works and the motor is alive.

Thanks

I am getting strange results? When I try to program the chip, it fails saying no comm 3 found. The only way I can program the chip is by removing my PSU. I am using my PSU to power the motor, and batteries to power the chip. Is this due to the serial output going into the ULN chip?

ZOR said:

I am getting strange results? When I try to program the chip, it fails saying no comm 3 found. The only way I can program the chip is by removing my PSU. I am using my PSU to power the motor, and batteries to power the chip. Is this due to the serial output going into the ULN chip?

Click to expand...

I think you'd better post a circuit diagram / or a high quality photo!

My setup uses just ONE power source.

e

See page 2 of
http://www.picaxe.com/docs/axe117.pdf

The AXE-17 pcb is populated using all the parts supplied. It has battery connection. The motor is mounted off the board, and is powered with 5 volts from a PSU (in case higher current wanted) and the 0v ground is commoned up to the AXE-117 ground.

I replaced the ULN2003A and it cured the programming problem just once, the next time it failed, and would only get programmed if I removed the PSU supply. So maybe another ULN chip has gone.

I'm not going to waste any more time soon, I was going to do all this with a 555 and decade counter. This should have been easy by all accounts but is now becomming a pain.

Why on the AXE-117 board is there no pad connection to Pins 1 and 16?
Why is there not a jumper between the serial output and Pin 2 of the ULN chip.

Okay it's project board, but could have been better for the price.

I just hope coming over to this thread I don't lose continuity of the Stepper motor

Thanks

ZOR said:

The AXE-17 pcb is populated using all the parts supplied. It has battery connection. The motor is mounted off the board, and is powered with 5 volts from a PSU (in case higher current wanted) and the 0v ground is commoned up to the AXE-117 ground.

Click to expand...

And have you connected the ULN2003A V+ pin correctly (pin9) to your second supply by adapting the PCB, this would be essential (AXE117 is only designed for / configured for a single supply setup). It may be worth having a look at the datasheet for the 2003A if you plan to modify the board for two separate supplies (which is not necessary at all if using a 5V supply anyway).

ZOR said:

Why on the AXE-117 board is there no pad connection to Pins 1 and 16?

Click to expand...

2003A has 7 internal darlington drivers - 14M2 has 6 portB outputs... so one driver is not required.

ZOR said:

Why is there not a jumper between the serial output and Pin 2 of the ULN chip.

Click to expand...

Because it is not generally required.

Thanks again, however there are so many permutations that 4 wires can be moved.
I cannot be that far out as the motor is also supplied with a test board having the ULN chip in, and the picture clearly shows the motor color/order against the ULN2003A chip, which I would take to be the easiest track layout for connections on the board.

I do not understand why the AXE-117 has no track/pad on pin 16 of the ULN2003A chip, so losing 1 input of the darlington??
Hope somebody with the same motor can tell me exactly what is wrong in my connections.

Click to expand...

The board supplied with the stepper has 3 unconnected inputs and outputs - as they are not needed.
Without a photo it is hard to help - as I PM'd I can lend you a driver board.

Thankyou.
Now I understand.

I have just removed the motor from the output of the darlington drivers, and the PSU motor supply.
I put 4 led's into the 4 ULN outputs to ground. I thought if I looked at what was comming out I might understand a bit more what the motor sees.

In just one direction (clockwise) there was a repetitive pattern,

B.1 off B.2 On B.3 On B.4 off
B1.on B.2 on B.3 on B.4 on
B.1 off B.2 On B.3 On B.4 off
B1.on B.2 on B.3 on B.4 on

Therfore B.1 and B.4 going on/off, but B.2 and B.3 never going off

The change overs, from 2 to 4 LED's being on 1 second approx, and from 4 to 2 LED's on 2 seconds approx

Does this look correct?

I thought the outputs of the darlingtons had to go totally low for the motor.

Thanks

Wish I had not moved over to this posting as it all feels disjointed now, as code etc on other posting.

I have now added in the reverse code and the LEDS all behave differently so sorry I might have wasted peoples time on the last entry. Thisnk I might just give this one up.
Regards

Check for a solder bridge/ short circuit - the pattern should "ripple"

ZOR said:

I put 4 led's into the 4 ULN outputs to ground.

Click to expand...

No - you really need to understand the basics of darlington drivers / ULN2003A chip before you go any further. Read it up in part 3 of the PICAXE manual.

LEDs go from 2003A outputs to V+, not to ground.

Thankyou, now it looks sense. I am going to run code line by line to see what sequence there is and try and correlate it to what the stepper coils want to see. Seems so long winded but the only way I can find out how to wire up the motor. Everywhere I look I just seem to get Bipolar information, and yet these servo motors on Ebay must have been used by others out there. Never mind, many other ways to go mad.

Thanks Jim, when I changed the pause/delay timings the LEDS did ripple. But now I need to slow them right down to get to the switching sequence.

Regards

ZOR said:

Thankyou, now it looks sense. I am going to run code line by line to see what sequence there is and try and correlate it to what the stepper coils want to see. Seems so long winded but the only way I can find out how to wire up the motor. Everywhere I look I just seem to get Bipolar information, and yet these servo motors on Ebay must have been used by others out there. Never mind, many other ways to go mad.

Thanks Jim, when I changed the pause/delay timings the LEDS did ripple. But now I need to slow them right down to get to the switching sequence.

Regards

Click to expand...

A little favour please.

Can you post a photo or two,
so we all know what we're looking at?

e

I have just looked at the step by step output from the darlingtons.
1) B.1 and B.3
2) B.1 and B.4
3) B.2 and B.4
4) B.2 and B.3

Then repeated until 1 clockwise direction covered.
Two pictures, 1 shows AXE-117 and the other is a connector board for the stepper. (fly leads)
I had a battery pack feeding the AXE-117, and a PSU for the 5 volts + for the stepper motor. Did not know what current the motor may have taken, did not want to burn up pcb track.

Last post only allowed two pictures. This just shows the AXE-117 with battery pack and LED's to look at sequence



My Motor windings

Thanks

blue and yellow into B.1, B.2
orange and pink into B.3, B.4
red to V+

try it - if it doesn't work then reverse blue/yellow and try again.

Use a single supply, not 2. Batteries are fine.

Your photo also looks like it is a gearbox stepper - so will take many steps for the outer spindle to rotate.

Many thanks Technical, it's moving.
For the benefit of anyone else getting this motor from Ebay, using the AXE-117, my motor connections were:
Blue - B.1
Pink - B.2
Yellow - B.3
Orange - B.4
And thanks to eclectic for the code to get me off the ground and others that came in.