As situations would have it, I have installed and tested the unit with an IR Range Finder, simply by hooking up to the PC board already running the Power Chair.

From here I could install four sensors like this one, one at each corner, and as long as the speed was reasonably low, I believe the bot/power chair could navigate it`s way around fairly easily.

I believe I will do an experiment with sensors on the serial bus late, because I actually want to be able to remotely control the thing. I believe I want to take an existing remote controlled computer (that is programmable, of course) and use it to allow someone who is willing to hack their power chair, to be able to pull it up beside their car, or even drive it into a van on a ramp.

In the stories I hear, a simple inexpensive mechanism to give people a remote controlled chair would be a very big help to disabled power chair users everywhere.

Next stop: Wireless Remote Control!

`------------------------------------------------------------------------------
` COMPILER DIRECTIVES / SYMBOLS
`------------------------------------------------------------------------------
#picaxe 18m2
` -------------------------------------------------
`--------------------------------------------------
` PicAxe 18M2
` Pinout and Definition of Legs
`=======================================
`(DAC / Touch / ADC / Out / In) C.2 leg 1
`(SRQ / Out) Serial Out / C.3 leg 2
`(In) / Serial In / C.4 leg 3
`(In) old reset is now signal C.5 leg 4
`---------------------------------------
`(gnd) 0v leg 5
`---------------------------------------
`(SRI / Out / In) B.0 leg 6
`(i2c sda / Touch / ADC / Out / In) B.1 leg 7
`(hserin / Touch / ADC / Out / In) B.2 leg 8
`(pwm / Touch / ADC / Out / In) B.3 leg 9
`=======================================
`---- package bottom -- direction up ----------
`=======================================
`(i2c scl / Touch / ADC / Out / In) B.4 leg 10
`(hserout / Touch / ADC / Out / In) B.5 leg 11
`(pwm / Touch / ADC / Out / In) B.6 leg 12
`(Touch / ADC / Out / In) B.7 leg 13
`---------------------------------------
`(vcc) +v leg 14
`---------------------------------------
`(Out / In) C.6 leg 15
`(Out / In) C.7 leg 16
`(Touch / ADC / Out / In) C.0 leg 17,in0
`(Touch / ADC / Out / In) C.1 leg 18,in1
`
`=======================================

`--------------------------------------------------------------
`--------------------------------------------------------------
` Actual Code starts Here
` by using a prototyping board we can make modifications
` which will allow us to test feasibility of sensors, etc
` using a power Chair Wheelchair
` This version gives us standard IR sensor
` It gives motor control f/b, l/r
`
` ***
` Make the changes on the PCB
`--------------------------------------------------------------
`--------------------------------------------------------------
`
` set these according to the way you wired your board
symbol in3 = b.7
symbol en34 = b.2

symbol in1 = b.5
symbol en12 = b.3

symbol IRdet = C.0

symbol i2csda = B.1
symbol i2cscl = B.4


symbol checkVal = w0 `where the sensors talk to the bot
symbol IRdetVal = w1 `where the bot sees ahead
symbol rRange = b4 `= (w2)range limits
symbol lRange = b5 `= (`w2)range limits
symbol Xcnt = b6 `= w3
symbol Ycnt = b7 `= (w3)
symbol maxStor = w5 `= w5

symbol adc_delay = 5 `Let ADC settle (can be 1 or 0)

let dirsb = %10111110
let pinsb = %00000000

pause 1000

` set motor drivers to known position
` turn all motor enables OFF
` stop everything
initi:
low en34,en12,in1,in3
let checkVal = 0 `init the check values register to 0
pause 1000

main:
`inline checks of robot condition
`stop, analyze, react appropriately
`make this check so fast it is a blur
`monitor the pb, then start the mover forward until strategy
gosub updateIR
if IRdetVal < 300 then
gosub moveForward
else gosub holderNute
endif
pause 500
goto main



`----------------------------------------------------
` Sensing Routines
`
updateIR:
`Look at the IR det- also monitor and interrupt
`load value in a register
`use a loop routine that watchs the register
`identify corner/front/back and apply appropriate reaction
readADC10 IRdet, IRdetVal
pause adc_delay
`sertxd("IRdetVal : ", #IRdetVal,13,10)
return



````````````````````````````````````````````````````````
`` :DRIVE CONTROL
`
moveForward:
high in3
high en34
pause 10
return

moveBackward:
low in3
high en34
pause 10
return

stopFB: ` stop forward/backward motion
low en34 `drive off
pause 10
return

turnRight:
high in1
high en12
pause 10
return
turnLeft:
low in1
high en12
pause 10
return

stopTurn: ` stop right/left motion
low en12 `drive off
pause 10
return

holderNute:
low en12 `drive off
low en34 `drive off
pause 10
gosub moveBackward
pause 200
low en12 `drive off
low en34 `drive off
gosub turnLeft
pause 300
low en12 `drive off
low en34 `drive off

`turn on a light or something
return