good morning to everyone, i have just found this site and hope somebody can help as im stuck!!!
what i need:
i require a circuit using a 555 timer to drive a relay but here is the tricky bit,
this will need to be a monostable trigger circuit that uses trimpots to decide
1: the sensitivity of the trigger
2: duration of output from relay
the input source will be from the cars accelerator pedal (potentiometer) which reads between 0v and 5v,
what i need is something that can determine when the pedal is backing off (dropping to 0v) not accelerating (rising to max 5v)
i know this kit exists as i have a top picture of the circuit in question but no values or circuit diagrams - if needed i could post the pic.
these modules are extremely expensive and the company who used to make them no longer provide them.
so to sum up i require a monostable circuit that triggers when the input trigger falls from anywhere between 5v and 0v, the voltage is not important it just needs to "sense" that the voltage is dropping then trigger a relay for a max duration of 3s but must reset when voltage starts to rise again ( so when i push the pedal down by any ammount the system would reset then as soon as i let the pedal come up it would trigger for max 3s then switch the relay off???????????
i know this is one hell of a brain freeze or at least it has been for me.
i have limited knowledge of electronics but can learn extremely quickly.
i have mad various circuits but they will only trigger from a set voltage not a falling one
many thanks in advanve
graham
what i need:
i require a circuit using a 555 timer to drive a relay but here is the tricky bit,
this will need to be a monostable trigger circuit that uses trimpots to decide
1: the sensitivity of the trigger
2: duration of output from relay
the input source will be from the cars accelerator pedal (potentiometer) which reads between 0v and 5v,
what i need is something that can determine when the pedal is backing off (dropping to 0v) not accelerating (rising to max 5v)
i know this kit exists as i have a top picture of the circuit in question but no values or circuit diagrams - if needed i could post the pic.
these modules are extremely expensive and the company who used to make them no longer provide them.
so to sum up i require a monostable circuit that triggers when the input trigger falls from anywhere between 5v and 0v, the voltage is not important it just needs to "sense" that the voltage is dropping then trigger a relay for a max duration of 3s but must reset when voltage starts to rise again ( so when i push the pedal down by any ammount the system would reset then as soon as i let the pedal come up it would trigger for max 3s then switch the relay off???????????
i know this is one hell of a brain freeze or at least it has been for me.
i have limited knowledge of electronics but can learn extremely quickly.
i have mad various circuits but they will only trigger from a set voltage not a falling one
many thanks in advanve
graham