TheBackShed.com

Forum Index : Microcontroller and PC projects : MM2 random number on startup

Author

Message

GoodToGo!

Senior Member

Joined: 23/04/2017
Location: Australia
Posts: 188

Posted: 11:04pm 02 Apr 2020

Copy link to clipboard

Print this post

Howdy all,
I hope you are all well in these trying times.
I have multiple LED lighting modules powered by E28's that are designed to flash 3-wire Xmas lights. As a part of the Basic routine, there are multiple sub-routines with the flashing sequences. Upon startup I seed the Random generator with the Timer and then use it to select 1 of the 5 routines as a starting point. Reason being I don't want all the modules to start at the same routine. Great in theory, doesn't work in practice due to all modules seeding the same timer time of course.
I was thinking of maybe using a 'programming resistor' and measure the analog input voltage and use that as a seed? Different resistors should give different voltages, meaning different seed values meaning different random numbers meaning different starting points....
Can anyone else think of a way to generate differing random numbers on module start?

Cheers,

GTG!

...... Don't worry mate, it'll be GoodToGo!

OA47

Guru

Joined: 11/04/2012
Location: Australia
Posts: 899

Posted: 12:08am 03 Apr 2020

Copy link to clipboard

Print this post

GtG, could you use the onboard clock to supply current uS value to start as your seed?

OA47

Phil23
Guru

Joined: 27/03/2016
Location: Australia
Posts: 1664

Posted: 02:06am 03 Apr 2020

Copy link to clipboard

Print this post

How many E28 Modules?, And I'm Guessing they don't talk to each other.

Just boot & then run one of the 5 sequences & then switch to an alternate random one after a random time?

Turbo46

Guru

Joined: 24/12/2017
Location: Australia
Posts: 1593

Posted: 06:11am 03 Apr 2020

Copy link to clipboard

Print this post

Could you have a 'start' button for each that you must press to start the sequence? That would add randomness to the startup.

CaptainBoing has discussed random number generation using a noise generator on the Fruit of the shed, see here and here. You can find more circuits on the web.

Bill

Keep safe. Live long and prosper.

TassyJim

Guru

Joined: 07/08/2011
Location: Australia
Posts: 5900

Posted: 06:50am 03 Apr 2020

Copy link to clipboard

Print this post

> AUTOSAVE
spare = 23 ' any spare analog pin left floating.
setpin spare, ain

RANDOMIZE pin(spare)*1000

print rnd()
Saved 53 bytes

> RUN
0.300794
> RUN
0.0807553
> RUN
0.830729
> RUN
0.62072
> RUN
0.270705
> RUN
0.170715
> RUN
0.370797
>

Jim

VK7JH
MMedit MMBasic Help

GoodToGo!

Senior Member

Joined: 23/04/2017
Location: Australia
Posts: 188

Posted: 07:43am 03 Apr 2020

Copy link to clipboard

Print this post

Quote GtG, could you use the onboard clock to supply current uS value to start as your seed?

I originally did, using RANDOMIZE(TIMER). But because all the E28's are connected to the same time switch, they all appeared to use the same TIMER value.

Quote How many E28 Modules?, And I'm Guessing they don't talk to each other.

Just boot & then run one of the 5 sequences & then switch to an alternate random one after a random time?

5 so far, they are all independent except for their power source which is switched on by a 230VAC timer. They all run through the sequences in turn, and then repeat.

Quote > AUTOSAVE
spare = 23 ' any spare analog pin left floating.
setpin spare, ain

RANDOMIZE pin(spare)*1000

print rnd()
Saved 53 bytes

> RUN
0.300794
> RUN
0.0807553
> RUN
0.830729
> RUN
0.62072
> RUN
0.270705
> RUN
0.170715
> RUN
0.370797
>

Jim, that's perfect! I did try using a high-ish value resistor between pin 7 and the 3.3v supply, which worked, but I also found it worked with the resistor removed! Much better than seeding from the TIMER value in my case.

Thanks for all your help everyone!

Cheers,

GTG!

...... Don't worry mate, it'll be GoodToGo!

Print this page

To reply to this topic, you need to log in.