picaxe 28x project board and easy driver 4.4 hook up

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nickwoodrow

New Member
Happy new year! I am trying to run a 12v stepper (with 6v) using seperate voltage connected and the l294 has caught fire! I have an easy driver 4.4 which works well on the Arduino uno using only 3 wires and is very easy to "hook up"!! but the coding is driving me crazy and I much prefer basic. Can anybody show me how to bypass the L294 driver and hook up the Easy driver using the picaxe 28x1 board please?? Also, how does this affect the coding? Many thanks in anticipation. Be gentle with me
 
bfgstew

bfgstew

Senior Member
What stepper? Photo's, schematic, code............................please post so folks can at least see what you are using.
 
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nickwoodrow

New Member
HI bjfstew here is link to similar on ebay. http://www.ebay.co.uk/itm/CNC-Nema17-for-1-7A-3400g-cm-40mm-length-4-Lead-2-phase-Wantai-Stepper-Motor-/170796197566?pt=UK_BOI_Industrial_Automation_Control_ET&hash=item27c43f26be

code i snatched from somewhere on the web! drives stepper a few degrees and then will eventually fire a camera shutter! cheers!
symbol counter =b0
start:
for counter =1 to 8 '*****degrees rotation
High 4 'coil 1 step I forwards
low 5 'coil 2 step 1forwards
low 6 'coil 3 step 1forwards
high 7 'coil 4 step 1forwards
pause 50 '****waits, seem smoother higher number*********
high 4 'coil 1 step 2forwards
low 5 'coil 2 step 2for .v•ards
high 6 'coil 3 step 2fa/wards
low 7 'coil 4 step 2forwards
pause 50 'waits 500 milliseconds
low 4 'coil 1 step 3[orwards
high 5 'coil 2 step 3forwards
high 6 'coil 3 step 3forwards
low 7 'coil 4 step 3forwards
pause 50 'waits 500 milliseconds
low 4 'coil 1 step 4forwards
high 5 'coil 2 step 4[orwards
low 6 'coil 3 step 4forwards
high 7 'coil 4 step 4forwards
pause 50 'waits 500 milliseconds
next counter
pause 3000 'fire camera in this time
goto start
 
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rossko57

Senior Member
The sample code is useless to use with Easy Driver. That requires two signals ; a logic level to tell it direction, and a pulse to make it step. Choose two outpin pins on the Picaxe, and find out what duration pulses are likely to work with your Easy Driver, and what gaps to leave inbetween them
 
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Paix

Senior Member
@Nickwoodrow, the 42BYGHW609 stepper motor that you indicated is a 3.4V motor with 2 Ohms per phase. Not a 12V motor as you claimed, so I'm not necessarily surprised that something gave out. Luckily it was the L294 chip and not the motor and Picaxe that was damaged(?)

I suspect that running at 6V, you will need some resistance in the motor leads but I have no first hand experience and will have to leave that to others to advise you.

PS, did you have any video footage of the event - purely for diagnostic purposes you will understand - LOL :) Fire . . . yipee! Take care. Always make the initial test with a finger on top of vulnerable packages and if they get hot switch off before the smoke escapes. Flames indicate that the smoke has already left the building!
 
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nickwoodrow

New Member
rossko57 said:
The sample code is useless to use with Easy Driver. That requires two signals ; a logic level to tell it direction, and a pulse to make it step. Choose two outpin pins on the Picaxe, and find out what duration pulses are likely to work with your Easy Driver, and what gaps to leave inbetween them
Click to expand...
The question is, hw do i connect one?
 
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nickwoodrow

New Member
Paix said:
@Nickwoodrow, the 42BYGHW609 stepper motor that you indicated is a 3.4V motor with 2 Ohms per phase. Not a 12V motor as you claimed, so I'm not necessarily surprised that something gave out. Luckily it was the L294 chip and not the motor and Picaxe that was damaged(?)

I suspect that running at 6V, you will need some resistance in the motor leads but I have no first hand experience and will have to leave that to others to advise you.

PS, did you have any video footage of the event - purely for diagnostic purposes you will understand - LOL :) Fire . . . yipee! Take care. Always make the initial test with a finger on top of vulnerable packages and if they get hot switch off before the smoke escapes. Flames indicate that the smoke has already left the building!
Click to expand...
I am listening! will test at 4 v and see what happens in the next hour or so (damn visitors)! thanks
 
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MartinM57

Moderator
Doesn't look a very matched driver/motor combination to me...

Motor voltage is largely irrelevant (see Q1 and the rest of the Q's on http://schmalzhaus.com/EasyDriver/) when using a driver, and the motor's current rating is 1.7A vs a maximum easy driver capacity of 750mA

You also need to send the correct pulse and direction signals to the easy driver - again, see the questions on the web page above
 
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nickwoodrow

New Member
Question is (was) please could somebody, if willing, show me how to connect the easy stepper to the picaxe 28x1 board please?
 
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nickwoodrow

New Member
MartinM57 said:
Doesn't look a very matched driver/motor combination to me...

Motor voltage is largely irrelevant (see Q1 and the rest of the Q's on http://schmalzhaus.com/EasyDriver/) when using a driver, and the motor's current rating is 1.7A vs a maximum easy driver capacity of 750mA

You also need to send the correct pulse and direction signals to the easy driver - again, see the questions on the web page above
Click to expand...
Thanks for the advice, already been there, doesn't explain how to connect to picaxe 28x1 board! (not to my no electronic eyes anyway!) what/how do I program/fin out the correct pulse and signal lines? please (I am one of those ignorant noobie- hence the small fire)!!!!
 
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rossko57

Senior Member
If you have this working on Arduino already, it is difficult to see what you are trying to achieve here if you don't have much idea of where to start? Is it a learning exercise? That's fair enough, and people will be glad to help you. But not many will design and develop your project for you, and you won't learn much that way.

To connect Easy Driver to Picaxe: Choose two outpin pins on the Picaxe, connect one to E-D "direction", connect the other to E-D "pulse". Connect the Picaxe 0v to E-D 0v. Make a note of which output pins you used, because you will need that info later when you begin to program. If you are not sure how to do any of that, we may not get much further.
 
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MartinM57

Moderator
As well as rosko57's second paragraph, the 'firmware' section of https://www.sparkfun.com/tutorials/400 shows how to wiggle the chosen pins with appropriate high/low levels (direction signal) and pulses (step signal)

...if you still haven't a clue, look at the PICAXE manuals for the HIGH, LOW, FOR...NEXT statements etc
 
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oracacle

Senior Member
this should be easy, providing we disregard the fact that the driver is only rated for 50% of the current of the motor.

i presume you know where the 5v and ground needs to go, then attatch the dir and stp on jp2 to your chosen picaxe output, pulsout the step pin, high and low the direction pin.

however i would suggest you investigate a driver that is able drive the motor

heres a quick program i wrote for use with the THB6064 driver board for my heavy duty macro rail project (FYI, the motor i am using is almost identicale to your, bu slightly higher quoted torque)

Code: 
[color=Navy]#revision 1[/color]
[color=Black]#picaxe28x2[/color]
[color=Blue]setfreq m16

symbol [/color][color=Black]clk        [/color][color=DarkCyan]= [/color][color=Blue]b.7
symbol [/color][color=Black]enb        [/color][color=DarkCyan]= [/color][color=Blue]b.6
symbol [/color][color=Black]dir        [/color][color=DarkCyan]= [/color][color=Blue]b.5

      let [/color][color=Purple]dirsc [/color][color=DarkCyan]= [/color][color=Navy]%00000000
      [/color][color=Blue]let [/color][color=Purple]dirsb [/color][color=DarkCyan]= [/color][color=Navy]%11111111[/color]
[color=Black]init:
      [/color][color=Blue]let [/color][color=Purple]pinsb [/color][color=DarkCyan]= [/color][color=Navy]%00000000
      [/color][color=Blue]pause [/color][color=Navy]1000
      [/color][color=Blue]high [/color][color=Black]dir
      
      [/color][color=Green];initialise driver
      [/color][color=Blue]pulsout [/color][color=Black]clk, [/color][color=Navy]10      [/color][color=Green]'end clock pulse
      [/color][color=Blue]low [/color][color=Black]enb                [/color][color=Green]'endble
      [/color][color=Blue]pause [/color][color=Navy]100
      [/color][color=Blue]pulsout [/color][color=Black]clk, [/color][color=Navy]10      [/color][color=Green]'send clock pulse
      [/color]
[color=Black]main:
      [/color][color=Blue]for [/color][color=Purple]w2 [/color][color=DarkCyan]= [/color][color=Navy]0 [/color][color=Blue]to [/color][color=Navy]12800
            [/color][color=Blue]pulsout [/color][color=Black]clk, [/color][color=Navy]2
            [/color][color=Green]'debug
            'pause 10
      [/color][color=Blue]next [/color][color=Purple]w2
      
      [/color][color=Blue]pause [/color][color=Navy]1000
      
      [/color][color=Blue]let [/color][color=Purple]w2 [/color][color=DarkCyan]= [/color][color=Navy]0
      [/color][color=Blue]if [/color][color=Purple]b0 [/color][color=DarkCyan]=  [/color][color=Navy]1 [/color][color=Blue]then
            high [/color][color=Black]dir
            [/color][color=Blue]let [/color][color=Purple]b0 [/color][color=DarkCyan]= [/color][color=Navy]0
      [/color][color=Blue]else
            low [/color][color=Black]dir          [/color][color=Green]'change direction
            [/color][color=Blue]let [/color][color=Purple]b0 [/color][color=DarkCyan]= [/color][color=Navy]1
      [/color][color=Blue]end if
      goto [/color][color=Black]main[/color]
this was run the the driver set to 1/64 step which give 12800 micro step per rotation. you can remove the enable, well the entire drvier initialistion section unless your driver requires it


kit obtained from here: http://www.piclist.com/techref/io/stepper/THB6064/index.htm
 
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westaust55

Moderator
Based on the information known from first posts:

1. Stepper motor rated voltage 3.4 Volts
2. Stepper motor rated resistance 2.0 0hms
3. Stepper motor rated current 1.7 Amps

4. Supply voltage 6.0 volts

Then the current through the stepper motor windings will be 6/2 = 3 Amps.

At the very least you should review what stepper motor you will use and or what driver module (Easy Driver already indicated as only 0.75 Amps rating).

If you were to put a 1.5 Ohm 10 Watt resistor in series with each stepper motor winding you would limit the current to the motor rating of 1.7 Amps but still twice the E-D rating and the resistor will dissipate almost 5 watts of heat so even a 10 Watt resistor will get warm if not provided with a heat sink.

IMHO you need to review the components you have to prevent further fires before getting too worried about how to connect the PICAXE.
 
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MartinM57

Moderator
@WA55

...have a read of Q1 on http://schmalzhaus.com/EasyDriver/ - the EasyDriver will work with up to a 30v supply and still limit the current to its 0.75A maximum. The steady state DC (V, I and R) parameters of stepper motors are not particularly relevant to a stepper driver scenario - it's mostly dominated by L actually, but we're still at first base in this thread

..but you are correct in that there is a mismatch of components at the moment - but the OP in the first post seems to suggest that the EasyDriver does work with a Uno - whether that's theory or fact for this particular motor I'm not sure
 
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westaust55

Moderator
Noted the E-D limits the current to 0.75 Amps.
Motor Torque is a function of the current (ampere turns) so if the motor is lightly loaded then it will still operate/turn.
 
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nickwoodrow

New Member
Thanks all for your help and advice. I kind of don't know what I do and don't know! I so far have the axe20 running the stepper on 4.. 8 v through the picaxe driver chip (replacement) and it is running well having attached a heat sink. I will act upon all of your advice. Where can I post my completed project for you guys to see it? Happy new year. Live long and prosper!
 
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