Help with a SImple Calculation for the Interval Timer Kit MK

Kits General
1

HI Guys,

I hope you can forgive the question that will be very trivial for the experienced members hare i’m sure. I’m having trouble as i don’t have the knowledge or experience at the moment.

I’ve bought the Interval Timer Kit MK111 velleman.eu/downloads/0/mini … _mk111.pdf

I’m trying to work out how o modify it to have the following property a pause of 5 minutes and a pulse of less than 0.5 seconds

The default supports a pause of between 2.5 and 60 seconds and a pulse of between 0.5 and 5 seconds.

Is this possible and if so would anyone be kind enough to suggest some values of resistors and capacitors please?

Many thanks from Paul in North Wales

2

For 5 minutes, C3 needs to be roughly 5 times as big. Since electrolytic caps can feature up to 40% tolerance, we’d suggest 1000µF.
A pulse smaller than 0.5s with this circuit and a relay will be tricky and most likely unreliable. You might want to try decreasing R1, but do not use a value lower than say 220 ohm.

3

Thank you very much i will try this.

Paul