PIC Turns off and On with No program?

[fouadalnoor]

Hello guys,

I am using a PICAXE 08M to control a motor, but for some reason even when not connected to anything (when testing it by itself) the pic's output turns on and off a fair few times before it settles down. So when I have it blank it will just turn on and off a few times and then it will be OFF.

When I actually program it, it'll do the same, but then do what it's supposed to do...

I dont understand why it initially behaves in what seems to be non-random behaviour (it seems to always turn on and off 6 times) ? I know that it may be noise, but I did try to put a 0.1uF cap between the power pins, but still the same happens...

any ideas?

PS: The data sheet is found here: https://www.electro-tech-online.com/custompdfs/2011/06/picaxe_manual1.pdf

 

[Reloadron]

What exactly in detail are you using for the power supply? What pin is showing this out symptom?

Ron

 

[fouadalnoor]

I am using a "Project Board" that my lecturer gave me. It has a 5v supply and is called a "LD-2 Logic Designer" found here: **broken link removed**

Also, I am trying to measure a change in temperature from my cooker, can I use a thermocouple for this (and connect the heating end directly to the flame of the cooker?). How would I make sure that the voltage produced is not more than 5v (as I want to detect a flame using my PIC )

 

[colin55]

Power the device with 3 cells (4.5v) on short leads without anything else nearby and see what happens.

 

[Reloadron]

I would start as colin55 suggest using batteries to power the PIC. There has to be noise from somewhere to give the symptom you are seeing.

As to the cooker, placing a tc in a flame can be used as flame detection (there are other ways to do it also) if all you want to know is if a flame is present or not. Thermocouples deliver a very small mV signal that generally requires signal conditioning to be of any use. Here in the US older furnaces (gas fired furnaces) used a TC for flame detection on the pilot flame.

Before worrying about driving a motor or flame detection it would be best to get the uC behaving correctly.

Ron

 

[aljamri]

I am trying to measure a change in temperature from my cooker, can I use a thermocouple for this (and connect the heating end directly to the flame of the cooker?). How would I make sure that the voltage produced is not more than 5v (as I want to detect a flame using my PIC )

Thermocouple is used for High temperature applications, but it has many groups depends on the material it is made from, the temperature range and consequently the cost.

But I prefer to use optical component to detect the flame instead of measuring the temperature.

The out put of your sensor can be adapted to fit the microcontroller specs, by amplifying or attenuating it.