Linear Stepper Driver v0.9.2 Assembly Instructions Here's what's included in the kit: 1x Printed Circuit board 1x Heatsink bracket 5x 0.1uF capacitors 1x 6-pin ISP header 1x 10-pin configuration header 1x 2-pin reset header 4x TIP122 transistors 4x SS9014 transistors 2x 5-position terminal blocks 4x Nylon bushings 2x 4-40 x1/2" machine screws 2x 4-40 nuts 1x 10uF capacitor 2x 1W 1Ohm resistors 7x 10kOhm resistors 1x 14-pin DIP socket 4x mica TO-220 insulators You will need the following: Soldering iron Solder Small screwdriver Thermal paste 1) First, assemble the power transistors with the heatsink bracket. Place a nylon bushing and a TIP122 on each of the 4-40 screws, as shown 2) Next, put a small dab of thermal paste on the back of each of the two TIP122s. It doesn't take much! Then add a mica insulator to each.
3) Add a small dab of thermal paste to each insulator. 4) Now, add the rest of the stack in this order: Heatsink bracket Two dabs of thermal paste Mica insulator Two last dabs of thermal paste Remaining TIP122's Nylon bushing 4-40 nut Do not tighten the screws all the way at this point! You'll need to adjust them later, so leave enough slack so that you can still move the transistors a little bit. Place this assembly aside for now--you'll attach it at the very end. 5) Insert the low-profile components--the 0.1uF caps and the 10k resistors. 6) Solder the low-profile components from the back side, and snip off the excess leads. You don't have to do them all at the same time--if it's too tight, you can do just the resistors first, then insert and solder the capacitors.
7) Move on to the 1W resistors and the DIP socket. Solder and snip as before. 8) Insert and solder the terminal block near the transistors. Don't attach the other terminal block quite yet! 9) The headers come next. I did them all at once, but it is easier to insert and solder one at a time. 10) The 10uF capacitor gets a step all to itself. Watch the polarity! Insert, solder, and snip. 11) Add the second set of terminal blocks and the four SS9014 transistors. Make sure you insert the transistors correctly--the printing on the PCB will show you the right way.
12) You're almost done! Take the heatsink/transistor assembly that you made, and insert all 12 transistor legs into their holes. This step is tricky, so take your time. There should be a good amount of friction as you slide the transistors in. Once the transistors are in, go ahead an tighten up the 4-40 screws. 13) Solder the transistors in, and snip off the excess leads. Congrats--you're done soldering! 14) Insert the pre-programmed ATTiny24 microcontroller--make sure it lines up correctly with the printing on the PCB! One last step... 15) Place a Jumper on J2 to set the driver to single-stepping mode.
APPLICATION NOTES You're done! Well, you're done assembling the stepper driver. There are a few things you should note before you fire it up: 1) The heatsink bracket is NOT a heatsink. You'll have to provide your own. For lowpower applications, the bracket might be enough. Unlike the example here, your bracket has mounting holes on the top, spaced 1/2" apart. The holes are sized for 4-40 screws, but you can enlarge them if you need to. 2) This stepper driver is designed to supply 1 Amp. It can be modified for higher amperage (up to the 5A limit of the TIP122s) by replacing the 1 Ohm resistors as follows: 2A: 3A: 4A: 5A: 0.43 Ohm 2W resistors 0.26 Ohm 3W resistors 0.125 Ohm 3W resistors 0.06 Ohm 2W resistors The power rating on these resistors is the lowest integer greater than the expected power dissipation. There is no harm in using higher-wattage resistors, as long as the resistance is the same! 3) The step input is detected on a rising edge. 4) Microstepping is accomplished by adding jumpers to the 10-pin header as follows: J4 J3 J2 J1 Mode Off Off On Off Single-stepping Off On Off Off Half-stepping Off On Off On 1/3 stepping Off On On Off 1/4 stepping Off On On On 1/6 stepping On Off Off Off 1/8 stepping On Off Off On 1/12 stepping On Off On Off 1/16 stepping On Off On On 1/24 stepping On On Off Off 1/32 stepping On On Off On 1/48 stepping On On On On 1/96 stepping Note that the accuracy and effectiveness of microstepping will rely heavily on the characteristics of your stepper motor.
5) This kit is meant to be hacked! The ISP header is there to make it easy to reprogram, jumper J5 is unused, and source code is available at allgaiershops.com. We only ask that any changes and/or improvements made to the code be contributed back to the community. Questions? Comments? Derogatory Remarks? Send 'em to info@allgaiershops.com!