Hi clever folks.

I was searching for a solution to my problem, found something similar in your forum but it wasn’t quite what I was after, so I joined up in the hope that you might be able to help.

We have small bottles of insulin that are used twice a day, that have to be kept refrigerated. If they are left out of the fridge for more than a couple of hours they’re ruined, and they are very expensive.

I am trying to build an alarm to prevent this from happening.

So I made a holder for the bottle, with a switch at the bottom which is ‘closed’ when the bottle is lifted out.

It would be very annoying if the alarm went of as soon as you removed the bottle, so what I wanted to add was a delay of, say 2 minutes [to allow someone to take the bottle out and fill a syringe] before an alarm goes off to remind them to replace it.

I have very limited knowledge of electronics, though I’m fairly logical and know which end of a soldering iron to hold.

I bought this unit to function as the delay, hoping to use it with a 9v battery and a buzzer of some sort (which I have yet to source), however it came with no instructions or schematics and I can’t get it to do anything useful.

thanks in advance for any help!

Nick

 

Can you give us a link to that board please.

 

Of course https://www.ebay.co.uk/itm/192421886348

My question, which I didn't really make clear, is - is this module right for the job, if yes then how would I use it? If no, could you recommend a module that is?

Thanks so much.

 

I found this image which will mean more to you than to me...

 

Ideally, you need your switch to connect power to the circuit so that while the bottle is in place no current will be drawn so the battery would have a good life.
You will need to do some experiments with your board.
Connect a voltmeter between the output pins.
Connect a suitable power supply and watch the voltmeter. Note the tests will be quicker if the pot is adjusted to a fairly short delay time.
If nothing happens on the voltmeter, press the button and check that you see something happening on the voltmeter.
Post what you see.

 

OK will do that when I get home. Thank you.

 

Hi clever folks.

I was searching for a solution to my problem, found something similar in your forum but it wasn’t quite what I was after, so I joined up in the hope that you might be able to help.

We have small bottles of insulin that are used twice a day, that have to be kept refrigerated. If they are left out of the fridge for more than a couple of hours they’re ruined, and they are very expensive.

I am trying to build an alarm to prevent this from happening.

So I made a holder for the bottle, with a switch at the bottom which is ‘closed’ when the bottle is lifted out.

It would be very annoying if the alarm went of as soon as you removed the bottle, so what I wanted to add was a delay of, say 2 minutes [to allow someone to take the bottle out and fill a syringe] before an alarm goes off to remind them to replace it.

I have very limited knowledge of electronics, though I’m fairly logical and know which end of a soldering iron to hold.

I bought this unit to function as the delay, hoping to use it with a 9v battery and a buzzer of some sort (which I have yet to source), however it came with no instructions or schematics and I can’t get it to do anything useful.

thanks in advance for any help!

Nick[/QUOTE
At this type of alarm mechanism you need a switch open when bottle is taken out.
reason: when contact open alarm is on when cable or contact malfunction alarm true.
statement: alarm is always on unless a save condition is reached.
Save condition: power and temperature correct and bottle in.
Temperature when bottle in should stable for a defined period of time.

Please be extreme careful with medicine condition containers.

Picbuster

 

Hi again

OK… so my 9v battery is measuring 8.72v.

With battery connected + to VCC and - to GND (on the left hand side of the diagram above), the output (across the terminals OUT / GND on the right hand side of the diagram above) measures 0.05v.

If I then connect IN to VCC output is 7.2v.

If I then disconnect IN from VCC output drops back to 0.05v after the user-set delay time.

Does that help?!

Seems like that's pretty much the opposite of what I'm after...?

 

Try connecting a capacitor, perhaps 100n, from IN to VCC then monitor the output as you connect the power.
With a bit of luck the output will go high for the delay time...

 

But surely I want the voltage to be low for the delay time, then go high enough to activate a buzzer afterwards?
I'm afraid I don't have any components, would have to order them in, so this might take a while. I get the feeling I'm wasting your time here, and maybe I should just do some research and but the right module in the first place...?

 

You could connect the buzzer between the output pin and VCC then the buzzer will activate after the time delay.

 

Aha! Just tried that and it works, however only if the timer is manually triggered. The timer doesn't start automatically (I tried with and without IN connected to VCC)

 

I think a capacitor across IN and VCC will get it doing what you want.

 

OK thanks - so a 100n capacitor? I see you're from the UK - used to have a Maplins round the corner but they've gone now so I'll have to order on line. Could you recommend a buzzer module that would work for this? Might as well get it all from eBay...

Thanks so much for your help.

 

Be careful with buzzers. There are two different kinds of things called buzzers.
1. A simple piezo disc which makes a sound if you feed it with some AC.
2. A more complicated version which makes a sound when you feed it with a DC voltage.
You need the second kind.

Your profile doesn't say where you are in the world but if you are in the UK then this would do the job:
https://www.ebay.co.uk/itm/Piezo-Bu...nkw=buzzer&_from=R40&rt=nc&_trksid=m570.l1313

 

I'm in London - I might try and find an old fashioned shop where I can get advice about what I'm buying.

Again, thank you so much.

 

One more question! These..?

https://www.ebay.co.uk/itm/Pack-of-10-100nF-5mm-50V-general-purpose-disc-capacitors/112428923894

 

Yep, they'll do.
Please remember I am guessing that the capacitor will work - I don't have the circuit diagram for that board.

 

It's not a huge investment, so no big deal if it doesn't work. I've ordered them, will let you know how it goes! Thanks again.

 

Hello again. Well, I got the the components you recommended, and it nearly works! Thanks so much. The only problem is that when I connect the battery, the voltage between the output pin and VCC is 1.5v, and then when the timer is up, it jumps up to 9v. So the buzzer comes on immediately and then changes pitch after the set time, rather than coming on after the timer has elapsed. So close. Any ideas?!