Picaxe 08m2 in "low power-mode" ;-)

jscottb

Active member
I saw a YT video that got me thinking about a similar problem I had. In pulling the parts together, I decided to not use a low-power uC in it and instead use a 08M2 that has no LP option. Here's my bodge-up :)

 

lbenson

Senior Member
Nice project. Very neat. I like using those pwm modules--very convenient. Regarding lack of a "deep sleep" feature, it's really not a problem with the picaxe, unless you consider 11 years on 3-AA batteries insufficient: https://picaxeforum.co.uk/threads/low-power-battery-backup-reference-design.8353/

That code would, I believe, work unchanged for monitoring a PIR, since it currently monitors a pin for activity (which it never saw in that 11 years). But your big problem regarding draining the battery isn't going to be the picaxe--that requirement will be swamped by what your LEDs need when they're on. It depends on what kind of lighting you want--garden pathway lighting works with dollar store solar lights, even, I believe, with significant shading. If you want real working light, it's a different matter. I've experimented with probably a dozen or more types of 12V LED lights, with varying degrees of satisfaction. I'd be interested to see what you come up with for LEDs.
 

jscottb

Active member
Thanks. I should have been a better communicator! Yeah, I know the pics have some LP capabilities and I should have said more, but my thought train is quite "sporadic" at times, I'm ADHD and autistic and my brain and mouth don't get along most of the time ;-). It's good to be antisocial some times because of it. I will have a look at the code in detail, thank you for sharing it. I may fold it in my project. One of the things I did change in my code was to ramp the LED's up to full-on, to help manage current in-rush. I should have done this to begin with as I do it with motors to help with that.

I'm not sure what LEDs I will end up using in the building and had 12v whites at the start of the night but ended up with the 5v ones at the end. I'm going to have a 12v large cell in the building that I will trickle charge via speaker wire or the like from my garage. The indoor light will get very little use, but the outdoor will get a bit more on-time. I will put an LDR on that controller for night-time usage only. I may make a panel of 12v whites for the inside but will have an outdoor LED light that will run at 12v. I need to look into that at some point but will sort out the battery and charger first.

Thanks,
Scott
 

lbenson

Senior Member
a 12v large cell in the building that I will trickle charge via speaker wire or the like from my garage
That sounds like a plan. This is the best 12V LED I've found so far for close-to-120V lighting (and dimable) : https://www.ebay.com/itm/12V-70W-7000LM-LED-Panel-Strip-COB-Ceiling-Light-Tube-Lamp-220X120mm-White-Warm/293384558271

I also like these: https://www.ebay.com/itm/48W-16LED-Work-Light-Flood-Beam-Bar-Car-ATV-Off-Road-Driving-Fog-Lamps-12V-24V/283651397142
 

premelec

Senior Member
@Ibenson - I wonder if you have "looked into" the 16 LED unit to see what sort of regulator it has perhaps to make it dimable and or rewire a bit for 2x2 or 3x3 switchable LED configurations? thanks...
 

lbenson

Senior Member
I wonder if you have "looked into" the 16 LED unit to see what sort of regulator it has perhaps to make it dimable and or rewire a bit for 2x2 or 3x3 switchable LED configurations?
I haven't looked inside, but the 16-LED 12V light is easily dimmable with a picaxe with PWM @ 1kHz and IRLZ44N or like MOSFET or mosfet module: https://www.ebay.com/itm/5-Pcs-kit-IRF520-MOSFET-Driver-Module-For-Arduino-ARM-Raspberry-Pi-33-24mm-New/353148084178

I can't say about lighting subsets of the LEDs, but at $4.64 each you can't lose much. As it happens, yesterday I was in an electrical supply store where they had a similar (but certainly more sturdily constructed) 16-LED module for $120+ Canadian (about $100USD).
 

premelec

Senior Member
Interesting - with the wide input voltage range [Working Voltage: 9-32V DC ] I assumed there is an integrated switching power module - which I guess is OK with PWM input... have you noticed any RFI issues? I ordered one so will eventually know more... thanks...
 

lbenson

Senior Member
have you noticed any RFI issues?
None that I have noticed, but I don't know exactly what I would notice it in. With one 12V module I was testing (I've tried a lot), I got flicker at a quite dim level, and it may have been mains-synchronized flicker, but I don't remember exactly which LED.
 
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