Interfacing SRF05 to PICAXE

[jinx]

pic srf small.PNG (204.12 kB . 671x191 - viewed 430 times)

parts required:
                       PICAXE base shield
                       srf05 ultra sonic sensor
                       Dupont Male to Female Jumper

                          This snippet written in Picaxe BASIC and is  written for the axe 401 shield with the distance displayed in the terminal window of the editor.  first note that am using the shield pin definition "s.2"  rather than the PICAXE pin definition  c.0  but either will do the compiler will sort it out. Second is the setfreq which sets the internal clock frequency of the MCU and the 28x2 defaults to 8MHz which is fine but the maths will need altering on this line in the code :                                                                                                                                                let range = range * 10 / 62    
  refer to the manual for more on the maths.


 
wiring connection:   

srf05 wiring.PNG (211.95 kB . 635x452 - viewed 1036 times)
   

 with the code snippet

Code: [Select]

#picaxe 28x2
#no_data
#no_table

symbol trig     = S.2            ' pin b.2 Define output pin for Trigger pulse
symbol echo   = S.8            '  pin C.0 Define input pin for Echo pulse
symbol range  = w1             ' 16 bit variable for range

symbol delay = 30

init:
    setfreq m4             '
    pause 100
do
    pulsout trig,2                                       ' produces a  20uS pulse (must be minimum of 10uS)
    pulsin echo,1,range                             ' measures the range in 10uS steps
    pause 10                                              ' recharge period after ranging completes
    let range = range * 10 / 62                  ' multiply by 10 then divide by 62
    sertxd("Range is" ,#w1,13,10)         ' display range via terminal
    pause delay                                               
loop
                                                      happy building Jinx.

LINKS:
   SRF05 data sheet: http://www.picaxe.com/docs/srf005.pdf
  technical sheet :http://www.robot-electronics.co.uk/htm/srf05tech.htm