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variable timed switch?

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legepe

New Member
Hi all
Is it possible to build a variable timed switch that can fit into a space of around 20mm x 15mm which would have a range of something like 10min to 5hrs
Ive done some googling/youtubing but there doesnt seem to be anything suitable.
The only thing ive found which looks ok is https://www.ebay.co.uk/itm/152478915048
Can anyone give me advice, Im a complete newbie
Thanks
legepe
 

Pommie

Well-Known Member
Most Helpful Member
Sounds like a job for a microcontroller. How will you change the range? Can you program?

Mike.
 

gophert

Well-Known Member
Most Helpful Member
What voltage and current are you switching?
Let's play, "guess the voltage & current" before the OP responds.
My guess is 120VAC and 10 amps.
 

Pommie

Well-Known Member
Most Helpful Member
The last switch I designed was 12kV at 650A back in 1981. Designated the LNC12, I can still find the odd one here in Australia.

Hopefully the op only needs to switch something light.

How thick can it be?

Mike.
Edit shouldn't "before the OP responds" be "if the ...."
 

gophert

Well-Known Member
Most Helpful Member
Edit shouldn't "before the OP responds" be "if the ...."
Umm, no. What fun would guessing be if he doesn't return and let us know who wins.
 

legepe

New Member
Hi guys and thanks for replying...
Sorry for delay... its 12v and around or upto 4000 mah.. your the winner ronsimpson!
 

AnalogKid

Well-Known Member
Most Helpful Member
Something requiring programming like a microcontroller will be the least physical effort. For a one-off I'd consider a picaxe. All hardware certainly is possible, looks like two or three chips and a power MOSFET. One thought has it programmable in 10 minute increments with combinations of five shunts or a dipswitch.

ak
 

legepe

New Member
Something requiring programming like a microcontroller will be the least physical effort. For a one-off I'd consider a picaxe. All hardware certainly is possible, looks like two or three chips and a power MOSFET. One thought has it programmable in 10 minute increments with combinations of five shunts or a dipswitch.
would it be possible to have shunts like: 10min / 30min / then 1 hr / 2 hr / 3hr and so on?
I dont have any real experience with building electronic circuits.. and I dont have knowledge of programing.. would it be relatively straight forward?
What other components would I need to complete the circuit?
Is the https://www.ebay.co.uk/itm/152478915048 not more suitable especially considering my lack of experience?
Thanks a lot..
 

gophert

Well-Known Member
Most Helpful Member
Hi guys and thanks for replying...
Sorry for delay... its 12v and around or upto 4000 mah.. your the winner ronsimpson!
Note that mAh is a battery rating for the energy that is stored in a battery, 4000 mAh can supply 100 mA for 40 hours. How many amps does your device need?
 

legepe

New Member
Note that mAh is a battery rating for the energy that is stored in a battery, 4000 mAh can supply 100 mA for 40 hours. How many amps does your device need?
What i want to do with the switch is shut down a supply for a set time, create an open contact for that time chosen, then once the time is lapsed it will create a closed contact, a time again will then be manually chosen.. regarding the actual mah's of device is not important, however it will need to be this battery power that drives the circuit
 

Pommie

Well-Known Member
Most Helpful Member
Let's try a different question, how long does your battery last powering your secret device?

Mike.
 

gophert

Well-Known Member
Most Helpful Member
What i want to do with the switch is shut down a supply for a set time, create an open contact for that time chosen, then once the time is lapsed it will create a closed contact, a time again will then be manually chosen.. regarding the actual mah's of device is not important, however it will need to be this battery power that drives the circuit

We need to know the current draw of the mystery device to recommend components for your switch.
 

legepe

New Member
We need to know the current draw of the mystery device to recommend components for your switch.
If it were on full time it would last like gophert said.. around 40hrs but it will not be on full time and would last much longer... but when its on it will have a current draw of around 4000mah
 

Pommie

Well-Known Member
Most Helpful Member
If it lasts 40 hours and your battery is 4000mAh then it needs 100mA. You're confusing battery capacity with current consumption. Assuming your battery IS 4000mAh. Please confirm.

Mike.
 

gophert

Well-Known Member
Most Helpful Member
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