Compact 10-minute delay with transistor, don't want to use special IC

[KlausST]

Re: Compact 10 minute delay with transistor , dont want to use special IC

Hi,

i have no idea where you live, and about quantity and so on..

i understand all your points about manufacturing

... but now i read about oscillator and earphone driver and size:
this all for me make a ATTINY (or any other small micro) perfect for your solution.

* soldering of an SO8 device (ATTINY) should be possible, even by hand. Buti don´t know if it is available for you
* all other parts are in the size of 1206 or 0805 or tanatal size "A" or "B", all solderable by hand.
* all the parts ne less than 10 x 15 mm of place and 3 mm in height.

and now the new information about oscillator and earphone driver.
* it is already built in the ATTINY, you just need one or two port pins and a small and cheap piezo disc, soldered on the backside of pcb.
* if you use a 3V coin cell battery then you even need less parts (no resistor and no zener for power supply)
* you don´t even need a power switch, because the micro in power down needs less than 1 uA. It works for years.

Size: You will fit four of these circuits in a tictac box. OK, at least three ;-). with battery and buzzer!
And for programming, i am sure you will find somebody here in this forum (or other forum) who lives next to you...
***********

Capacitor:
I just looked into a datasheet of a 1000uF, 6.3V electrolytic capacitor:
Size: 10 mm diameter, 12 mm in length
Leakage current 0.01CV or 3uA --> here 3uA. With that value and a 150k resistor it is impossible to charge the capactior to more than 11.6V at 12.V. And any voltage between 11.6v and 12V is not reliable.
You definitely need a better one than this one.

***********

But for sure i can´t see your possibilities about manufacturing and availability and these things....


Good luck


Klaus

 

[onoffman]

Re: Compact 10 minute delay with transistor , dont want to use special IC

All people seniors thanks for all the answers , learning is the best part here .

KlausST ,
i know about ATTINY .. i write linux kernel drivers on a daily basis so coding for ATTINY is as easy as wiping
a pair of shoes. I even soldered 200+ pin ARM9 chip with hand.
[ even made a hot air gun out of aquarium pump ]

just making things simple for the newbies .


production models sure 8bit MCU can sing even music in tictac box
even polyphonic music from many boards (just a possibility )

 

[BradtheRad]

Re: Compact 10 minute delay with transistor , dont want to use special IC

A counter IC (or two) will take up less space than a large capacitor.

Example, 4020, 4060. There are low power versions as well. Possibly miniaturized types.

Or a couple of 4017 decade counters, arranged in cascade.

 

[KlausST]

Re: Compact 10 minute delay with transistor , dont want to use special IC

Hi,

I hope you are not upset about my last post.
This was not my intention.

Klaus

 

[onoffman]

Re: Compact 10 minute delay with transistor , dont want to use special IC

Hi,

I hope you are not upset about my last post.
This was not my intention.

Klaus

Klaus ,
Not at all .There is always good to learn for me .



BradtheRad,
counters need >3V vcc , clock etc .

This NAND gate timer circuit

**broken link removed**
is a good candidate

The low voltage 74LCX00 can be used with 2 button cells . Issue is many markets you dont get
74LCX00 .user will be struck in online international parcel shopping.
Many cant do that or ready to take the hassle.

 

[colin55]

Re: Compact 10 minute delay with transistor , dont want to use special IC

You could use a PIC10F200. It's only 1206 and no other parts. But it's expensive at 33 cents. China sells it for 5 cents.

- - - Updated - - -

"With that value and a 150k resistor it is impossible to charge the capacitor to more than 11.6V at 12.V. And any voltage between 11.6v and 12V is not reliable. "

You are forgetting the Schmitt Trigger action of the circuit. Voltages 10v to 12v do not apply.

 

[ahsan_i_h]

Re: Compact 10 minute delay with transistor , dont want to use special IC

This NAND gate timer circuit

**broken link removed**
is a good candidate

The circuit uses 4011 nand gate. It is not a good idea to apply such long duration analog signal to the input of 4011. They should use schmitt trigger gate in place of IC1. (e.g. 4093)

 

[onoffman]

Re: Compact 10 minute delay with transistor , dont want to use special IC

The circuit uses 4011 nand gate. It is not a good idea to apply such long duration analog signal to the input of 4011. They should use schmitt trigger gate in place of IC1. (e.g. 4093)

constraints
Vcc-3V
no special chip (uC alike )
yes 4093 may be possible but SMD version is not found in many markets
and DIP will not fit

collin,
Avoiding imports ....there are 10 chips that can do this if I import .

 

[onoffman]

Re: Compact 10 minute delay with transistor , dont want to use special IC

A counter IC (or two) will take up less space than a large capacitor.

Example, 4020, 4060. There are low power versions as well. Possibly miniaturized types.

Or a couple of 4017 decade counters, arranged in cascade.

Many IC dont fit in the smallsize(avoiding smd )