PWM Stepper Motor Driver PART NO. 2183816 Control a stepper motor using this circuit and a servo PWM signal from an R/C controller, arduino, or microcontroller. Onboard circuitry limits winding current, allowing you to use any bipolar stepper motor and any supply voltage from 6-36V. The circuit will operate the stepper motor analogous to a standard or continuous rotation servo depending on the mode. Half and Full step modes are also supported. Warning: Stepper Motor must not be driven in excess of 2A per winding. Input PWM signal must be 5V. If voltage input through servo PWM cable is greater than 5V, the red pin should not be connected to the board and 5V should be supplied through X1. See more information and updates at: https://sites.google.com/site/theelectronbazaar/home/projects/pwm-stepper-motor-controller Time Required: 30min depending on experience Experience Level: Intermediate Required tools and parts: Soldering Iron and Solder Tweezers or hemostat or small pliers Helping hand Tape Flat head screwdriver R1-R2 Power resistor: PWR163S-25-R500J Bill of Materials: Qty Jameco SKU Component Name 1 288067 IC1 Stepper Driver 1 245403 IC2 Stepper H-bridge 1 -- IC3 ATtiny24A-PU Microcontroller (NOT included, must be purchased elsewhere) 10 36265 D1-D8 Diodes 10 36038 D9 Small Signal Diode 10 2081932 D10-D11 LED 10 36097 D12-D13 Zener Diode 50 691180 R3 22k resistor 2 241146 R4, R12 10k potentiometer 10 2157167 R5, R8-R9, R11, R13 10k resistor 10 2158910 R6-R7, R10 10 544905 C1 3.3nF capacitor 10 609545 C2 0.1uF capacitor 10 330431 C3-C4 2 149948 S1-S2 tact switches 2 117560 JP1-JP4 4p headers 3 2144884 JP2, JP5-JP6 2p headers
1 109576 JP3 3p header 10 15747 JP7 2x3 header 1 189668 X1 terminal block 10 37162 IC3 socket 10 38607 IC1 socket 1 129242 Heat Sink 1 34121 Heat Sink mounting kit 10 112432 Shorting Block 1 PCB Step 1 - Layout parts Make sure the kit includes all the parts listed in the instructions. Notice the polarity of certain parts, particularly the diodes and capacitors. Step 2 - Install R1, R2 First, melt a small amount of solder onto the two small pads of the D2PAK footprint, as shown in the image. Second, hold the resistor on the board with pins on top of the solder using tweezers. Third, hold the soldering iron on the pin and solder to melt the solder around the pin. The pin may not be completely flush with the pad. Finally, hold the soldering iron on the heat sink tab and heat sink pad simultaneously and add solder once it flows onto the tab and pad. One resistor is on the top side of the board and the other is on the bottom. Step 3 - Install X1 and JP1 Insert one component at a time on the top side of the board in the locations marked with the part identifiers X1 and JP1. Use tape to secure the part, flip the board over, and solder the leads to the pad. Due to the large pad size, it will take time for solder to flow over the leads of X1.
Step 4 - Install D1-8 First, using small pliers (preferably one with round tips as shown), bend the leads to form a U shape. Second, insert the diode into the corresponding holes on the top side and solder on the bottom side. Watch the polarity. The white stripe on the diode should match the white stripe on the board. Step 5 - Install D9, 12, 13 Insert D9 (1N4148, smaller package), and D12 and D13 (1N7433, slightly larger package) into the corresponding footprints on the top of the board. Make sure to follow the polarity indications by lining up the black band on the diode with the white stripe on the board. Tape and solder the leads on the bottom of the board. Clip the leads once the solder cools.
Step 6 - Install all standard resistors First, find R3 a 22k ohm resistor (red-red-orange) and insert it into its footprint on the top of the board. Next, find R6 R7 and R10 all 330 ohm resistors (orange-orange-brown) and insert them into the corresponding footprints. Then find R5 R8 R9 R11 and R13 all 10k resistors (brown-black-orange) and insert them into their footprints. You do not need to worry about orientation. Tape to secure, then flip the board and solder the resistor leads on the bottom of the board. Step 7 - Install LEDs D10 and D11 Insert one LED into the D10 footprint with the long lead closest to neighboring R7 (longer lead towards the top of the board if reading D10 right-side-up). Insert the other LED into the D11 footprint with the long lead closest to the D11 text (towards the left side of the board when reading D11 right-side-up). Tape secure and solder the leads on the bottom of the board. The LEDs should be concentric with the white arcs on the board as shown.
Step 8 - Install capacitors Insert the small yellow capacitor into the C1 footprint. It is nonpolar, so you do not need to worry about orientation. Next, insert C2 a 0.1uF capacitor into its footprint and ensure that the pin closest to the negative stripe on the capacitor body enters the pad marked "-". This pin is also the shorter of the two. Do the same for C3 and C4, except with 1uF capacitors. Tape secure and solder the leads on the bottom of the board. Step 9 - Install remaining headers Insert a 2x3 pin header into JP7, a 1x4 pin header into JP4, a 1x3 pin header into JP3, and a 1x2 pin header into JP2, JP5, and JP6. Tape secure and solder the stubs onto the bottom pads. Neighboring headers may be difficult to tape in place when loose, so you may solder a few headers at a time.
Step 10 - Install pushbuttons Insert the pushbuttons S1 and S2 into their respective footprints. They will snap into place and therefore do not need to be secured while soldering. Finally, solder the leads to the bottom side pads. Step 11 - Install potentiometers R4 and R12 Insert the potentiometers into the R4 and R12 footprints. Orientation does not matter, although you may want to place them such that the non-marked face aligns with the outside of the boards.
Step 12 - Install IC2 Find IC2 labeled L298N. Insert it into the IC2 footprint. You may have to bend the leads slightly for it to fit. If the IC is loose, tape to secure. Finally solder the IC. Fix any bridging between pads. Step 13 - Install sockets for IC1 and IC3 Insert the 20 pin socket into the footprint for IC1 and the 14 pin socket into the footprint for IC3. Align the notch in the socket with the box or semicircle on the white outline of the IC. Tape to secure and solder the bottom pads. Insert the IC labeled L297 into the socket for IC1, again aligning the notches. Do the same for IC3.
Step 14 - Install heatsink Place the heatsink next to the L298 tab with fins facing the right of the board. Insert the parts in the mounting kit as follows: left of board screw head - heatsink - insulator - L298 tab - white washer - metal spring washer - nut right of board. Note: Large motors will draw large amounts of current, some of which the driver dissipates as heat through the heatsink. Therefore you may need to replace the heatsink and/or use fans to cool the driver and possibly sense resistors R1 and R2. If the heatsink still becomes excessively hot or the driver shuts down, you may be using a stepper motor with too high current rating. Step 15 - Connect Power and Input Look at the board horizontally with the text right side up. X1 should be on the right side. Connect the stepper motor power supply to the middle (V+) and top (GND) terminals of X1. If the input PWM signal (both V (red wire) and S (white wire)) has maximum 5V, leave the bottom terminal of X1 empty (this is the case for most microcontrollers, including Arduino). If you are in doubt about the voltage on the V line of the PWM cable, use a multimeter to measure its voltage reference to the black cable (ground). Connect the PWM cable according to the G V S marks on the three pin connector on the right side of the board. Alternatively, if the V (red wire) of the input PWM signal is greater than 5V, supply 5V to the bottom terminal of X1 and connect the ground to the top terminal along with stepper motor power ground (this is the case for most R/C controllers and the VEX system). Connect the PWM cable according to the G V S marks on the three pin connector on the right side of the board, but do not connect the V (red) wire. You may disconnect it by pulling the pin out of the housing, cut the red wire, or not supply any voltage on the red wire from the source device.
Step 16 - Connect stepper motor Connect the stepper motor wires to the 4 pin header just below X1. Positions 1 and 2 are for one winding and positions 3 and 4 are for the other winding. See your stepper motor datasheet for wire colors and winding information. Step 17 - Calibrate Chopper (R4) Calculate the sense voltage: 1.5*Winding current. With 5V and 12V power (either 12V through X1 and all pins of PWM cable plugged in or 12V and 5V supplied through X1 and power (red V wire) of PWM cable disconnected) and stepper motor attached, measure the voltage across the leads of R1 and R2. Adjust R4 as necessary until the voltage is below the calculated sense voltage. If the voltage is always above the sense voltage, you are using a stepper motor with current requirements greater than the board can handle (2A per winding).
Step 18 - Install jumpers Step Size: JP2: Half step mode when no jumper installed, full step mode when jumper installed. L297 chopper control JP5: chopper acts on individual windings when no jumper installed, all windings when jumper installed. See L297 datasheet for more details. Velocity/Position mode: JP6: Velocity control (continuous rotation) when no jumper installed, Position control (standard servo) when jumper installed. For beginners, the recommended setup is: JP2: no jumper JP5: install jumper JP6: depends on application Note for advanced users: to program the ATtiny via ISP, you must disconnect all jumpers since some I/O pins are shared. Also, the jumpers may be dynamically controlled but absolute limits in position mode may change. See schematic for more details.
Step 19 - Adjust Speed and run Adjust R12 to set the speed of the motor (in position mode) or the maximum speed of the motor (in velocity mode). Other notes: JP4 is provided in case direct access to the Enable, Direction, and Step lines are required, bypassing the PWM translation in the microcontroller (e.g. in a CNC where the PC gives such outputs). It is recommended that the microcontroller not be installed if such operation is desired. JP7 is provided in case the user wants to program the microcontroller using the AVR ISP interface. Pin 1 of the ISP header is marked on the board. D10 will indicate if 5V power is supplied to the board. If it does not turn on when 5V is supplied, check the power supply and ensure that a logic supply of greater than 5V was not supplied. D11 will indicate if the L297 counter is at the home position. The two pushbuttons will reset the microcontroller and L297 respectively.