PICAXE Speed Controller
d. bodnar
revised 04-08-11

 

The controller is very capable but made up of very few parts.  The schematic is shown below.  The main components are: PICAXE 18M2 microcontroller Infrared TV remote control Infrared receiver module DPDT relay (5 volt coil) IRL 530 Mosfet power transistor NPN transistor (2N2222) Indicator LEDs 7805 voltage regulator DC power supply (12 to 24 volts)

TV Remote The TV remote control is used to operate all functions of the controller.  The following buttons are used: Channel Up - increase speed Channel Down - decrease speed Volume > or < - change direction Mute - stop, remembering speed or start, at stored speed, after stop Return - enter configuration mode Number Keys - 1-->0 - enter configuration data

Using the Controller The controller is connected to a source of filtered DC of between 12 and 24 volts.  Its output is connected to the rails of the track. When first started the blue LED flashes out the software version number and the train's speed is set to zero. Press and hold the UP ARROW key on the remote control to speed up and the DOWN ARROW to slow down.  Use either of the VOLUME keys to change direction. Pressing the MUTE button at any time will stop the train.  Pressing it again will start it back up at the same speed that it was going when stopped. (optional) - if a sound device is installed press number buttons 1, 2, 3 or 4 to activate the corresponding sounds. To enter Configuration Mode press the RETURN button.  The unit will wait for you to enter 1, 2, 3 or 4.  These numbers select the following configuration modes:     1 Change Maximum Speed - the range is 0 to 255 with 255 being fast and 0 being stopped 2 Change Minimum Speed - the range is 0 to 255 with 255 - the minimum must be less than or equal to the maximum speed 3 Change Run Time - the range is 0 to 255 -  this is the time (in seconds) that the train will run in one direction before slowing, reversing and speeding up to the same speed.  Entering 0 will disable automatic reversing.  4 Change Acceleration / Deceleration rate - the range is 0 to 255 with 0 being very fast acceleration / deceleration and 255 being very, very slow acceleration / deceleration - the useful range is -0 to about 30.  Beyond 30 the rate is too slow. 5 (not yet set) - Change run time before slow down to minimum speed - this is the time in seconds that will elapse before the train changes speed from its maximum speed to its minimum 6 (not yet set) - Change Acceleration rate (independent of deceleration rate) 7 (not yet set) - Change Deceleration rate (independent of acceleration rate)

Software The software for the PICAXE 18M2 is shown here. C:\Shared_stuff\PICAXE-18M2\18M2-IR_motor_control-MultiFunctionv3-0.bas 1 2 'd. bodnar 4-6-2011 v3.0 Working Well! 3 Symbol Sound1 = b.4 'pin 10 4 Symbol Sound2 = b.5 'pin 11 5 Symbol Sound3 = b.6 'pin 12 6 Symbol Sound4 = b.7 'pin 13 7 Symbol Motor = b.3 'pin 9 8 Symbol Relay = b.0 'pin 6 9 Symbol Track = pinc.5 'pin 4 input only 10 Symbol T1 = b.1 'pin 7 11 Symbol IRSense = b.2 'pin 8 12 Symbol T3 = c.0 'pin 17 13 Symbol T4 = c.1 'pin 18 14 Symbol LEDBlue = c.6 'pin 15 15 Symbol LEDAmber = c.7 'pin 16 16 Symbol L3 = b.6 'pin 12 17 Symbol L4 = b.7 'pin 13 18 19 symbol Loop1 = b27 20 symbol Digit = b26 21 symbol Value = b25 22 Symbol ValueTemp = b24 23 symbol divisor = b23 24 symbol temp5 = b22 25 symbol temp = b21 26 symbol temp6 = b20 27 symbol TimeTemp = w5 28 Symbol ADRate = b16 29 30 symbol digitsbyte = b19 31 Symbol Loopie0 = W1 32 Symbol SetSpeed = w2 33 Symbol MinSpeed = w3 34 Symbol InfraRED = b12 35 Symbol TempStore= w4 36 Symbol TempByte = b18 37 Symbol WaitTime = b17 'pause before reverse 38 39 Symbol LStart = 0'120'450 40 Symbol TTrigger = 7000 41 Symbol Period = 150 42 Symbol PWMMin = 0'350 43 Symbol PWMMax = 1023'600 44 Symbol ChUp = 16 45 Symbol ChDown = 17 46 Symbol VolUp = 18 47 Symbol VolDown = 19 48 Symbol OK = 20 49 Symbol Retrn = 59 50 Symbol One = 0 51 Symbol Two = 1 52 Symbol Three = 2 53 Symbol Four = 3 54 Symbol Five = 4 55 Symbol Six = 5 56 Symbol Seven = 6 57 Symbol Eight = 7 58 Symbol Nine = 8 59 Symbol Zero = 9 60 Symbol Power = 21 61 Symbol VerWhole = 3 62 Symbol VerDecimal = 0 63 64 high sound1:high sound2:high sound3:high sound4 65 66 WaitTime = 0 67 ADRate = 10 68 Read 0, WORD SetSpeed 69 if SetSpeed = 0 then 70 SetSpeed = LStart 71 endif 72 SetSpeed=0 73 pwmout motor,50,500'150 ; set pwm duty 74 75 pwmduty motor, SetSpeed 76 for tempbyte=1 to VerWhole:high LEDBlue:pause 200:low LEDBlue:pause 200:next tempbyte:pause 900 77 temp=verdecimal 78 IF temp > 0 then 79 for tempbyte=1 to VerDecimal:high LEDBlue:pause 200:low LEDBlue:pause 200:next tempbyte 80 else 81 high ledblue:pause 10:low ledblue 82 endif 83 sertxd("d. bodnar",13,10,"4-6-2011 v3.0",13,10,13,10) '4800 baud @ this clock speed 84 85 Cruise: 86 if waittime=0 then SkipReverse: 87 if time >=WaitTime then 88 sertxd("Time= ",#time,13,10) 89 time=0 90 goto Revers 91 endif 92 SkipReverse: 93 Infrared=255 94 Irin [50, Cruise],IrSense, InfraRED 95 sertxd("IR= ",#infrared,13,10) 96 if InfraRED = Retrn then GetOption 97 if infrared= One then 98 low sound1:pause 200:high sound1 99 endif 100 if infrared= Two then 101 low sound2:pause 200:high sound2 102 endif 103 if infrared= Three then 104 low sound3:pause 200:high sound3 105 endif 106 if infrared= Four then 107 low sound4:pause 200:high sound4 108 endif 109 110 111 if InfraRED = VolUp or InfraRED=VolDown then Revers 112 113 if InfraRed = OK then 114 Sertxd("@ OK",13,10) 115 if SetSpeed > 0 then 116 TempStore=SetSpeed 117 gosub decel 118 SetSpeed=0 119 disabletime 120 pause 1000 121 else 122 SetSpeed = TempStore 123 gosub accel 124 enabletime 125 endif 126 endif 127 128 if InfraRED=ChUp then 129 high LEDAmber 130 SetSpeed = SetSpeed +5 131 pwmduty motor,SetSpeed 132 write 0, WORD SetSpeed 133 sertxd(#setspeed,13,10) 134 else 135 low LEDAmber 136 endif 137 if InfraRED=ChDown then 138 high LEDAmber 139 if SetSpeed > 5 then 140 SetSpeed = SetSpeed -5 141 sertxd(#setspeed,13,10) 142 endif 143 pwmduty motor,SetSpeed 144 write 0, WORD SetSpeed 145 else 146 low LEDAmber 147 endif 148 goto Cruise: 149 150 GetOption: 151 sertxd("@GetOption",13,10) 152 pause 1000 153 StayHere2: 154 Infrared=255 155 Irin [50, StayHere2],IrSense, InfraRED 156 sertxd("IR= ",#infrared,13,10) 157 if infrared >3 then 158 goto cruise 159 endif 160 161 Branch infrared, (speedmax, speedmin, runtime, acceldecelrate) 162 goto cruise 163 164 speedmax: 165 value = setspeed 166 gosub flashvalue 167 gosub getirnumber 168 setspeed=digitsbyte 169 sertxd("setspeed= ",#setspeed,13,10) 170 goto cruise: 171 172 speedmin: 173 value = minspeed 174 gosub flashvalue 175 gosub getirnumber 176 minspeed=digitsbyte 177 sertxd("minspeed= ",#minspeed,13,10) 178 goto cruise: 179 180 runtime: 181 value = waittime 182 gosub flashvalue 183 gosub getirnumber 184 waittime=digitsbyte 185 sertxd("waittime= ",#waittime,13,10) 186 goto cruise: 187 188 acceldecelrate: 189 value = adrate 190 gosub flashvalue 191 gosub getirnumber 192 adrate=digitsbyte 193 sertxd("adrate= ",#adrate,13,10) 194 goto cruise: 195 196 AutoReverse: 197 for b0=1 to 10:toggle IrSense:pause 100:next b0 198 goto cruise 199 200 Revers: 201 sertxd("@Revers",13,10) 202 gosub decel 203 toggle relay 204 pause 1000 205 gosub accel 206 goto Cruise: 207 208 Accel: 209 disabletime 210 low sound1:pause 200:high sound1 211 sertxd("@Accel",13,10) 212 for loopie0= PWMMin to SetSpeed step 5 213 sertxd(#loopie0," ") 214 pwmduty motor,loopie0 ; set pwm duty 215 pause adrate 216 next loopie0 217 sertxd(13,10) 218 enabletime 219 return 220 221 Decel: 222 low sound2:pause 200:high sound2 223 disabletime 224 sertxd("@Decel",13,10) 225 for loopie0= SetSpeed to PWMMin step -5 226 sertxd(#loopie0," ") 227 pwmduty motor, loopie0 228 pause adrate 229 next loopie0 230 sertxd(13,10) 231 enabletime 232 return 233 234 FlashValue: 'Flash out current reading 235 sertxd(13,10,"@FlashValue ",#value,13,10) 236 ValueTemp=Value 237 for Loop1= 2 to 0 step -1 238 if Loop1=2 then 239 divisor=100 240 endif 241 if Loop1=1 then 242 divisor=10 243 endif 244 if Loop1=0 then 245 divisor=1 246 endif 247 248 sertxd("divisor ",#divisor," ")'debug divisor 249 Digit=ValueTemp /divisor 250 sertxd("digit ",#digit," ",13,10)' debug Digit 251 temp5=Digit * divisor 252 ValueTemp=ValueTemp - temp5 253 sertxd("valuetemp ",#valuetemp," ",13,10)'debug ValueTemp 254 if Digit=0 then 255 high LEDAmber:pause 50:low LEDAmber:pause 100:pause 600:goto skipover3: 256 endif 257 for temp=1 to Digit 258 high LEDAmber:pause 200:low LEDAmber:pause 200 259 next temp 260 pause 600 261 SkipOver3: 262 next Loop1 263 return 264 265 GetIRNumber: 266 sertxd(13,10,"@GetIRNumber",13,10) 267 DigitsByte=0:digit=3 268 GetDigits0: 269 Infrared=255 270 irin [50, GetDigits0],irsense, InfraRED 271 sertxd("infrared ",#infrared," ",13,10) 272 if infrared > 9 then 273 return 274 endif 275 infrared =infrared +1 276 if infrared = 10 then 277 infrared=0 278 endif 279 if digit=3 and infrared>2 then getdigits0:'can't be above 2hunderds 280 if digit=2 and digitsbyte = 2 and infrared > 5 then getdigits0 281 if digit=1 and digitsbyte =25 and infrared > 5 then getdigits0 282 skiprnd: 283 sertxd("Digit= ",#digit,13,10) 284 if infrared=0 then 285 high LEDAmber:pause 50:low LEDAmber 286 endif 287 for tempbyte=1 to infrared:high LEDAmber:pause 200:low LEDAmber:pause 200:next tempbyte 288 DigitsByte=DigitsByte*10+infrared 289 digit=digit-1 290 pause 200':'command=0 291 if digit=0 then 292 sertxd("Digitsbyte ",#digitsbyte," ",13,10) 293 return 294 endif 295 goto GetDigits0: 296