IRIN Timeout Erratic

erco

Senior Member
I'm abusing IRIN, I'll admit. Instead of an IR receiver, I'm using a 433 MHz radio receiver per my post at https://picaxeforum.co.uk/threads/sending-ir-commands-over-radio-comms.31566/ I'm working on 2-way comms going between a robot and controller, and I'm getting long unexpected delays (up to several seconds, it varies) using a timeout with IRIN. I suspect there is some noise in these cheap radio receivers which is affecting PICAXE timeout. Hippy, Technical, can you comment on the nature of the timeout? Does any signal (non-SIRC code or noise) reset the timeout interval?
 
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hippy

Senior Member
Hippy, Technical, can you comment on the nature of the timeout? Does any signal (non-SIRC code or noise) reset the timeout interval?
Yes it does. The timeout is on lack of signal so noise which appears to be a signal to the PICAXE firmware will reset the timeout.
 

erco

Senior Member
Update: My project uses 2-way radio comms, the controller and robot each have a 433 TX and RX. Robot-to-controller comms are very simple, in fact it only needs to communicate 3 events. My workaround is instead of sending IR codes over the radio link, the robot sends a 1-second PWM signal of 3 different frequencies (I used 5000, 6000 and 7000 hz, 50% PWM) . The controller sends a regular stream of IR codes and periodically counts pulses coming from the receiver in a 10 ms interval to detect the events signaled by the robot. That brief count period is analogous to an IRIN timeout, which was problematic with the noise coming from the 433 radio link. Using this PWM/count technique, noise isn't a problem. The noise count in 10ms is always single digits, whereas those PWM frequencies yield counts of 50, 60 and 70. Works great.

BTW this relates to my thread HERE where I had to shut down the robot servos and PAUSE briefly before transmitting the PWM signal, then turning servos back on.
 
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