PICStep Microstepping Controller
I took a small webcam video of PICStep driving a 24inch linear stepper motor. Once I figured out how much current I could push through the coils the motor actually is quite strong. I would make an awesome x-axis in a gantry type CNC drilling machine/vinyl cutter as it's mechanical resolution running in 1/8th step mode is quite something (with no possible backlash!). It's fun to think what I'm going to do with this thing!
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| LinearStepperFinal.wmv | 988.94 KB |
| linear_stepper1.jpg | 49.88 KB |
| linear_stepper2.jpg | 11.38 KB |
| linear_stepper3.jpg | 36.9 KB |
A few small modifications to the existing V2.0 board. Basically just a few cosmetic changes like the addition of mounting holes (again!), removable of some redundant wire-links, and a slightly better routing of the ground. Otherwise it's exactly the same design, just on a slightly bigger PCB.
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| picstep_v2_1_small.jpg | 124.64 KB |
PICStep V1.0 firmware has been released! (Yippie!)
It now is fully functional on a PIC16F628A and includes some nice new tasty features!
New features include :-
- Automatic motor shutdown after around 6 minutes of inactivity (saves your motors from burning when your job is finished)
- Watchdog timer automatic reset (the controller will now automatically reset itself after 18ms if the PIC crashes)
- More optimized table look ups and interrupt handling (hopefully should yeild more RPM!)
- Works on a PIC16F628A (didn't before because of some stupid error on my part!)
So if you're interested in building a PICStep make sure your use the V1.0 firmware. I'll be posting the PICs to customers who've ordered them with V1.0 firmware today.
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| picstep_v1.0.zip | 10.25 KB |
Finally finished the PICStep PC interface board. It has an on-board 5v regulated supply, emergency stop / motor enable screw terminal, expansion header for three more PC outputs and five PC inputs (all with screw terminals).
It doesn't offer opto-isolation or anything fancy, so use a parallel port PCI card if you don't trust your wiring (or my designs :)
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| picstep_interface_v2.0.jpg | 107.38 KB |
| picstep_interface_v2.0_schema.jpg | 95.9 KB |
After many requests, here is a parts list of the PICStep V2.0 boards including part no. for Jaycar, Dontronics and DigiKey.
Resistors ------------- 5 x 10K 1/4W (R5, R6, R7, R8, R9) RR-0596 2 x 20K 1/4W (R1, R3) RR-0603 2 x 20K 1/4W (R2, R4) - Adjustable to set current limit Capacitors ------------- 2 x 2.2nF MKT (C1, C3) RM-7022 2 x 500pF Ceramic (C2, C4) RC-5333 2 x 1uF 100V MKT (C5, C7) RM-7170 2 x 470uF 63V Electro (C6, C8) RE-6210 1 x 100uF 16V Electro (C9) RE-6130 2 x 10nF MKT (C10, C11) RM-7065 Semiconductors ------------- 1 x PIC16F628A (U1) ZZ-8520 2 x LMD18245 (U2, U3) DIGIKEY LMD18245T-ND Misc ------------- 1 x 6 pin 0.1" Locking Header (CONN1) HM-3416 3 x 2 way PCB Mount Screw Terminal (CONN2, M1 x 2) HM-3172 1 x 10 way DIL Header (CONN3) HM-3250 1 x 4 way 8 pin DIL Switches (U4) SM-1020 1 x 20MHz 3 pin resonator (X1) Dontronics ZTT-20.00MX
Last night I knocked together another PICStep board, but this time using the professionally produced boards. The results speak for themselves!
They went together excellently! I only stuffed up a few hole sizes in the design (namely the 10 pin IDC should be 1mm not 0.8mm, and the 100uF electro should also be 1mm not 0.8mm), but apart from that it all went together like magic.
While building this board I took photos of each step and I plan to put together some basic building instructions and a complete parts list.
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| PICStep_Pro1_V2.jpg | 91.36 KB |
| PICStep_Pro2_V2.jpg | 81.48 KB |
| PICStep_Pro_V2.jpg | 71.81 KB |
A FedEx parcel landed on my desk and inside contained 12 fresh new professionally produced PICStep V2.0 boards!!!
The quality is awesome (I know it's just a single layer board and all, but I'm excited okay.. :P ) and I got a good price too. CustomPCB.com did an awesome job, and got them to Australia in under 5 business days too!
I've also just received a few more LMD18245's too, so I'll be constructing a couple of these boards to try out. If you'd like to purchase some of said boards they'll be $22 inc GST each.
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| PICStep-Pro-Board1.jpg | 93.77 KB |
| PICStep-Pro-Board2.jpg | 106.94 KB |
Again with the late nights, but not because of PICStep. I came home from a late meeting (11pm) and didn't feel ready for bed, so I took some photos and some crappy webcam footage of the PICStep running via TurboCNC.
You can see my current setting resistors sitting high above the board in their sockets because I haven't trimmed them down to the sockets while I'm still fiddling. You just pop in a new set of 1/4W resistors to set the maximum current of the driver (resistor = 20,000 / max coil current eg. 20000/0.7A = ~27K) and the LMD's take care of the rest!
I've thought of a decent way to do a self-test and also the motor timeout current limit. I'll set to work on the new firmware shortly.
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| picstep_motor_video.wmv | 656.96 KB |
| pic_step_testing.jpg | 67.43 KB |
| pic_step_testing1.jpg | 72.61 KB |
| pic_step_testing2.jpg | 54.98 KB |
