variable timed switch?

legepe · Mar 3, 2019

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 **broken link removed**
Can anyone give me advice, Im a complete newbie
Thanks
legepe

Pommie · Mar 3, 2019

Sounds like a job for a microcontroller. How will you change the range? Can you program?

Mike.

ronsimpson · Mar 3, 2019

legepe said:
switch

What voltage and current are you switching?

gophert · Mar 3, 2019

ronsimpson said:
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 · Mar 3, 2019

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 ...."

ronsimpson · Mar 3, 2019

gophert said:
Let's play, "guess the voltage & current"

Good guess. I will go with 12V, automotive.

gophert · Mar 3, 2019

Pommie said:
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 · Mar 4, 2019

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

AnalogKid · Mar 4, 2019

y o u ' r e

AnalogKid · Mar 4, 2019

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 · Mar 4, 2019

AnalogKid said:
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 **broken link removed** not more suitable especially considering my lack of experience?
Thanks a lot..

gophert · Mar 4, 2019

legepe said:
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 · Mar 4, 2019

gophert said:
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 · Mar 4, 2019

Let's try a different question, how long does your battery last powering your secret device?

Mike.

gophert · Mar 4, 2019

legepe said:
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 · Mar 4, 2019

gophert said:
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 · Mar 4, 2019

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.

legepe · Mar 5, 2019

Pommie said:
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.

Yes.. battery is 4000mah

legepe · Mar 10, 2019

Initially wasnt sure if I was getting a reply on here when I first posted this.. and guess I was a little impatient so I posted same question on https://forum.allaboutcircuits.com
Sorry for double posting... hope I can be forgiven

gophert · Mar 10, 2019

legepe said:
Initially wasnt sure if I was getting a reply on here when I first posted this.. and guess I was a little impatient so I posted same question on https://forum.allaboutcircuits.com
Sorry for double posting... hope I can be forgiven

Could you please explain what happened on that thread that caused it to be closed?

variable timed switch?

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