Progress
My FYP report is due on Friday. The demonstrations are then 1.5 weeks later. I doubt that my project will be 100% complete by friday so i'll be taking a gamble with the report and writing down that i finished everything. Then i'll have those 1.5 weeks so make that true.
I am pretty close to completion. I'm working on my IR barrier circuit and Charging station at the same time in UL. My IR circuit wasn't working for me until last week. This took me ages to try and fix and in the end it was pointed out by my supervisors that the duty cycle of my IR beam was too high. I would have never guessed this. The problem i was having is that the IR photodiode picked up the IR signal when the reciever and transmitter were in close proximity but when they were moved apart, after like 20cm, the signal was lost. My photodiode is a TSOP1136 so it detects a 36khz IR signal. At the transmitter i'm using a 555 timer to create this 36khz clock.
The duty cycle of a 555 timer is given by:
D = RB/(RA+2RB)
Where RA and RB are shown in this diagram:
Originally in my design i had RA = 22k-32k (variable resistor in series with 22k) and RB = 470ohm, clearly RA > RB, but for an even duty cycle this should be the other way around. So i changed my design to RA = 3K and RB = 15K
This gives me a duty cycle of roughly 50% which boosts the power to my IR led and now the photodiode is detecting it perfectly!
Now i'm going to pass the output of my photodiode into an ATTiny861. I have the AVR code written for this controller but i want to make it a bit more intelligent. Like, if the lower beam is only broken, but it stays broken for more than 2 seconds, then someone is probably crawling through so alert the robot. I dont know though, it's hard to think of things. I'm open to suggestions.
I am pretty close to completion. I'm working on my IR barrier circuit and Charging station at the same time in UL. My IR circuit wasn't working for me until last week. This took me ages to try and fix and in the end it was pointed out by my supervisors that the duty cycle of my IR beam was too high. I would have never guessed this. The problem i was having is that the IR photodiode picked up the IR signal when the reciever and transmitter were in close proximity but when they were moved apart, after like 20cm, the signal was lost. My photodiode is a TSOP1136 so it detects a 36khz IR signal. At the transmitter i'm using a 555 timer to create this 36khz clock.
The duty cycle of a 555 timer is given by:
D = RB/(RA+2RB)
Where RA and RB are shown in this diagram:
Originally in my design i had RA = 22k-32k (variable resistor in series with 22k) and RB = 470ohm, clearly RA > RB, but for an even duty cycle this should be the other way around. So i changed my design to RA = 3K and RB = 15K
This gives me a duty cycle of roughly 50% which boosts the power to my IR led and now the photodiode is detecting it perfectly!
Now i'm going to pass the output of my photodiode into an ATTiny861. I have the AVR code written for this controller but i want to make it a bit more intelligent. Like, if the lower beam is only broken, but it stays broken for more than 2 seconds, then someone is probably crawling through so alert the robot. I dont know though, it's hard to think of things. I'm open to suggestions.
