wondering if anyone can help i am trying to build a timer were a 12vdc supply is switched on and 5- 10 sec later a +12v signal is sent out to turn on a relay which in turn handles a larger load, this would be used in a negative ground automotive application any help would be greatly appreciated
Thankyou
Power-on delay can be realized in several ways, for example with the very popular 555-timer, but I would like to encourage you to use a small microcontroller, some times called the 555 of the new millennium, namely the PICAXE08 ..
You shouldn’t have problems in buying it in Australia (Altronics) ..
Programming in BASIC is incredible easy and all necessary tools are free (available from the same website as the above manual ..
The advantage of using this small (8-pin DIL) microcontroller is that if you change your mind about the way the device is to be switched on – such as different time delay, for example – the only thing that has to be modified is the program – hardware stays unchanged ..
Program may look like this:
Code:
main:
low 1 ‘ switch off output 1
pause 5000 ‘ wait 5 seconds
high 1 ‘ switch on output 1
Thanks IanP the programming will be a sinch as i use plc's all day and being an electrician i can understand basic electronic schematics so hopefully i can find a way of putting it all together
with kind regards Evbagnall
p.s. if i need a push in the right direction i hope you dont mind giving me a shove