Range sensor code question

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Pat13

Senior Member
Hello everyone, I am having troubles writing code for this application.
I need to monitor ranges in inches from 5 sources simultaneously and if range falls within a certain parameter, to trigger a piezo speaker.
I have a client who is legally blind (can see shapes within 3-8') and is now a quadraplegic.
We are going to put range sensors on her power wheelchair, one each left right and rear, and two on the front. Each sensor will be accompanied by a piezo speaker.
When she is with 18" to 24" of an object (say, a wall) I want the speaker on that side to emit a tone with a set duration, if she continues in that direction (12" to 17") i want the tone to increase in pitch and duration, if she continues (6" to 11"), again an increase in pitch and duration.
I ran debug on the senor and these are the readings I got:
at 3': 12/$0C/%00001100
at 2': 8/$08/%00001000
at 18": 6/$06/ %00000110
at12": 4/$04/%00000100
at 6": 2/$02?%00000010
Here is the code I have so far, View attachment Wheelchair Range Sensor.bas
I have run syntax and it is getting hung up on {if b1< 16}.
I think by using the "start" command, I can have this picaxe monitoring all 4 quadrants at once, but am stumped as how to write the byte variable. Any help greatly appreciated.
 
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westaust55

Moderator
Firstly, in using the Start0, Start1, Start2 and Start3 labels for multi-tasking please confirm that you have an M2 series PICAXE chip.

With your lines such as:
if b1< 16 'if chair is within 18"-24" of object gosub alarm1
then gosub alarm1

the THEN keyword MUST be lon on the same line as the IF.

In fact, if you are only branching from the IF&#8230;THEN commands the destination label should also be on the same line so you will have:
IF b1< 16 THEN GOSUB alarm1 ; if chair is within 18"-24" of object gosub alarm1
 
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westaust55

Moderator
Further to earlier response, for the data you have indicated there is a potentially better way to branch to the respective subroutines. Since the READADC value received increments by 2 for each 6 inches, then you could use some code such as:

value = b1 / 2 – 1 ; then give 0 for 6 inch, 1 for 12 inches, 2 for 18 inches etc
ON value GOSUB alarm1, alarm2, alarm3, alarm4, alarm5, alarm 6

Here alarm6 related to the 5th interval (0 to 5) = = > 6*(5+1) = 36 inches
For any greater distance, the ON. . .GOSUB will just all through to the next line of program code.
 
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Pat13

Senior Member
Thanks for the help. Yes, am using the 18M2, on the CHI-030 project board. I will try the code when I am in the office tomorrow and will post the results. Once we have the unit running on the wheelchair, will post a video of it in action. Thanks again.
 
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Pat13

Senior Member
boriz said:
Can you post the minimum code that demonstrates the problem?
Click to expand...
here it is
Code: 
	start0:
		readadc Range_RF,b1		'read range in inches into byte variable
		readadc Range_LF,b2
		
		if b1< 16 'if chair is within 18"-24" of object gosub alarm1 
	 	then gosub alarm1
 
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westaust55

Moderator
As already mentioned, fixing the problem by moving the THEN GOSUB xxx to the same line as the IF... does solve the problem

Here is a snippet of the original code
Code: 
'Wheelchair Range Sensor for client EK, clinically blind quadriplegic

symbol Range_RF=B.1
symbol Range_LF=B.2
symbol Range_R =B.3
symbol Range_L =B.4
symbol Range_RR=B.5

symbol Spkr_RF =C.0
symbol Spkr_LF =C.1
symbol Spkr_R = C.2
symbol Spkr_L = C.6
symbol Spkr_RR =C.7

main:
	start0:
		readadc Range_RF,b1		'read range in inches into byte variable
		readadc Range_LF,b2
		
		if b1< 16 then [B][COLOR="#006400"]gosub alarm1[/COLOR][/B] 'if chair is within 18"-24" of object gosub alarm1 
               [COLOR="#B22222"] ; gosub alarm1[/COLOR] ; remove here - it is now in the line above		
                GOTO Main ; added for for demo only
		
Alarm1:
	RETURN
 
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Pat13

Senior Member
We seem to have run into another issue. The piezo that we are using are not loud enough when powered with 5V. They are rated 5-30V. We are using a CHI030 board and of course, I can use the darlington side of the board with 12V, however. I need to have at least 4, preferably 5 inputs to readadc for the range sensors, correct. And according to the 18M2 specs only C.0, C.1 and C.2 have readadc. Is there a way that i can power the piezos off 12V but still use a couple of the B pins to readadc the sensors? The sensors are rated for 5V.
 
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eclectic

Moderator
A drastic but feasible method:

1. Saw off the top 6 legs of the ULN2803.

2. Connect jumper wires.

You then have inputs B.5, B.6 and B.7

e
 

Attachments

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Pat13

Senior Member
The board we are using is actually a CHI030A and has a strip between the picaxe and the darlington designated B.0 thru B.7. I'm sure I could use these once i cut off the appropriate legs of the darlington
 
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eclectic

Moderator
Pat13 said:
The board we are using is actually a CHI030A and has a strip between the picaxe and the darlington designated B.0 thru B.7. I'm sure I could use these once i cut off the appropriate legs of the darlington
Click to expand...
In that case, there seems no need to amputate anything.

Just don't connect to the right-hand outputs of the ULN2803

e
 
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