💬 Ikea Molgan Hack

[Yveaux]

MySensors sketch is still missing. After polishing I will add it to the repo ;-)

[scalz]

Sweet :+1:

[GertSanders]

hi Ivo, very nice to see this on OpenHardware.io
Any chance you find the time to reverse engineer the Molgan board, or did someone already do that ? I would like to see a schematic of the original board, to recreate it with some additions.

[Yveaux]

@GertSanders I made a start with it but didn't finish it. It is quite a standard design.

[Cliff Karlsson]

Are the components in the top right corner not needed?

[Yveaux]

@Cliff-Karlsson it's for a sha204. Only needed if you use hardware signing.

[Yveaux]

Added a basic sketch to the repo. Enjoy!

[david fagotin]

@openhardware.io

Hello
I would like to know if the pcb sold its virgin or mount.
Thank you in advance and congratulations for the work done...

[Yveaux]

@david-fagotin From what I understand the 10xPCB order is for bare PCB's.
A kit is in preparation from one of out suppliers, but I don't think it'll have the SMD parts mounted.
And ofcourse you can always make a donation to me :+1:

[david fagotin]

@Yveaux said:

From what I understand the 10xPCB order is for bare PCB's.
A kit is in preparation from one of out suppliers, but I don't think it'll have the SMD parts mounted.
And ofcourse you can always make a donation to me

If your kit goes out soon I will wait and I would give you a donation at that time !:stuck_out_tongue_winking_eye:

[LastSamurai]

Some short questions as I will start to assemble one of these very soon. Great work @Yveaux !

• What are the SJ1 and 2 parts on the pcb?Just some measurement points where I can cut the trace?
• Why did you put in the pullup for the CS line on the NRF? Never saw that one before
• The wire to the batterie spring is need to be able to use only 2 batteries for the addon pcb, right?
• But you use 3 batteries and both connection points to the main pcb still?
• Any particular reason why you did not make your pcb bigger so that it reaches the + from the main pcb too?

[Yveaux]

@LastSamurai

• What are the SJ1 and 2 parts on the pcb?Just some measurement points where I can cut the trace?

The solder jumpers are to support ATmega328PB. You need to open them when mounting an PB version.

• Why did you put in the pullup for the CS line on the NRF? Never saw that one before

Habit ;-) With multiple SPI devices on a bus it's good practise to have a pullup on all of the CS lines. Here it isn't really required though.

• The wire to the batterie spring is need to be able to use only 2 batteries for the addon pcb, right?

Yes, the addon runs on 2xAAA, the PIR on 3xAAA
By powering the addon with 2xAAA it can be powered directly without an extra voltage regulator.

• But you use 3 batteries and both connection points to the main pcb still?

The original connection points are still required to power the bottom PIR PCB. Both PCB's share a common ground.

• Any particular reason why you did not make your pcb bigger so that it reaches the + from the main pcb too?

This size I could fit more sub-PCB's in a panelized design for the board house. And, as said, the addon PCB doesn't require the + on the main PCB.

[GertSanders]

This one made it on the Adafruit blog:

https://blog.adafruit.com/2016/11/30/add-nrf2401-arduino-functionality-to-hacked-ikea-molgan-led-lamp-ikeausa/

Great Success Yveaux !!!

[Yveaux]

@GertSanders Awesome! Thanks for the tip man!

[LastSamurai]

I finished my first hacked molgan 2 days ago and it's detecting motion really well (and looks so much better than my custom builds).
So overall I love it but it also seems to have one problem: batteries...

I started it about 48h ago and the first reading was 2.119V but within some hours it dropped to 2.072V, though today it climbed back up to 2.096V. Thats still 23mV in ~2 days though.
Is this just the discharge curve and some imprecise readings? @Yveaux Whats the consumption of your modules?

[Yveaux]

@LastSamurai I don't have the exact figures at hand, but I had a look at the reported battery consumption of one of them. It dropped from 81% in August to 70% today.
I'd just let it run for a while and see how it goes.

[LastSamurai]

So yesterday my molgan started to constantly trigger, which I think might indicate that the voltage is too low. It has dropped down to 1950mV. I will try it with new batteries later today, but the power consumption still seems to be way too high compared to yours @Yveaux.
I have removed R17 to disable all leds and I have changed the fuses and used your sketch. Any idea what might have gone wrong?

[Yveaux]

@LastSamurai can you measure the consumption of individual parts? E.g. The Molgan hardware, the arduino and the radio?

[LastSamurai]

@Yveaux Ok I will try to do that. I did try other (new) batteries though and got the same values (about 2V strangely). Then it started to continuously trigger. I described the problem here.
It's so frustrating, but something seems to be wrong with my whole network I guess....

[Yveaux]

@LastSamurai how did you measure 2V? Measured with a DMM 2XAAA fresh alkaline batteries should be more in the 3V range. This makes a big difference, as at around 2V the Pir starts to behave weird, as you already experienced.