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#1

UEXT / Re: MOD-IRDA faulty ?

Last post by SirExie - December 20, 2025, 10:24:31 PM

Hi Folks,

Final post to wrap this thread up - its done, all working!

I soldered in the 20ohm resistor and saw the uplift in current, but still couldn't get the range. I used a laser pointer to align it with the target, but still no joy.

In the end I swapped out the LED with one:
https://download.altronics.com.au/files/datasheets_Z0880A.pdf

It's a larger 5mm one, but it fit on the board fine and it has a narrower viewport at 20 degrees, and a much higher radiant intensity. This did the trick and now it works perfectly, I appreciate I'm at the max 100mA that it supports, but as it is pulsed, nothing gets warm on the board so I think its going to be ok.

Thanks for putting up with my questions and vandalising your hardware. I should say thanks for making great kits and been open about sharing the schematics, without that I probably never would have tried this in the first place.

#2

UEXT / Re: MOD-IRDA faulty ?

Last post by SirExie - December 18, 2025, 01:33:24 PM

Thanks LubOlimex, I ordered some of these SuSuMu ones which came in 1/3W:
https://www.susumu.co.jp/common/pdf/n_catalog_partition08_en.pdf

They should arrive tomorrow and I'll have a go swapping it out.

#3

A20 / Re: A20 Board Power Consumptio...

Last post by plantedpig - December 17, 2025, 11:22:07 AM

On the A20 OLinuXino, idle power consumption with no peripherals connected is usually in the few hundred milliwatts range, depending on the OS and kernel configuration. True deep sleep support on the A20 is pretty limited, so most setups rely on aggressive idle tuning rather than full suspend. You can reduce power usage by lowering the CPU frequency and voltage (using cpufreq with the powersave governor), disabling unused interfaces in the device tree, turning off HDMI, Ethernet, and USB when not needed, and unloading unnecessary kernel modules. With some tuning, you can get idle consumption down noticeably, but it won't be ultra-low like an MCU-based system.

#4

New Products release / Re: MIPI-HDMI converter for ES...

Last post by ramblecube - December 16, 2025, 11:22:27 PM

Hello olimex,

Thanks for developing this product.

Would it be possible to add I2S audio support to this product?

The datasheet for the LT8912B (QFN64) says that pins 58 (I2S DATA) 59 (I2S WS) and 60 (I2S CLK) are for I2S, but your schematic shows that they are not connected on the board.

Could you add a breakout/connector for I2S in a future revision of this product?

Thank you,

-ramblecube

#5

A20 / Re: A20 Board Power Consumptio...

Last post by LubOlimex - December 15, 2025, 10:15:09 AM

These are power-hungry processors not designed with low power modes in mind, not a lot of current can be saved especially if you want to use the boards at their full capability. Yet, you can limit the CPU clock, the RAM clock and much more to reduce the power consumption to a minimum. Hard to say what is the minimum since it depends on the goals and what you are willing to sacrifice.

#6

UEXT / Re: MOD-IRDA faulty ?

Last post by LubOlimex - December 15, 2025, 09:31:06 AM

Is this about receiving or sending (both have 33R resistor)? I guess it is the sender. Changing R1 down to 20R should be alright. This will bring the current to absolute maximum of 100mA.

The 33R that we use is calculated as follows - supply 3.3V DC, forward voltage of SIR-32ST3F - 1.3V - means voltage is 3.3V - 1.3V = 2.0V

2.0V/33R~0.06A

If you use 20R - 2.0V/20R=0.1A

Refer to the datasheet:

https://fscdn.rohm.com/en/products/databook/datasheet/opto/optical_sensor/infrared_led/sir-34st3f-e.pdf

#7

A20 / A20 Board Power Consumption in...

Last post by annasm - December 15, 2025, 06:42:52 AM

Hi everyone, I'm using an A20 OLinuXino board for a low-power project. I'd like to know the typical power consumption of the board when it's in sleep or idle mode with no peripherals connected. Are there any recommended settings or tweaks to minimize power usage in this state? Thanks in advance!

Geometry Dash

#8

UEXT / Re: MOD-IRDA faulty ?

Last post by SirExie - December 14, 2025, 02:17:16 PM

Hi Folks,

Follow up post again, I now have it working, the protocol is correct, its not Whynter at all, its NEC!

But I'm now on to another problem, I cant get the range I want. Ideally, I'm looking for ~3m.

Looking at MOD-IDRA I notice it had a 33 ohm resistor which by rough maths makes it about 50mA (I think). It looks like a surface mount 0805 which I'm a chance at re-working.

So how bad would it be to put a 20R in there ? I should be about to get a .25W or maybe a .333W and this should push the IR diode a bit harder maybe 80-90mA ?

Sorry if its poor form to talk about hacking away at the Olimex product here, I'm not an electrical engineer, if this is a bad idea, just tell me and I'll come up with a different solution.

#9

UEXT / Re: MOD-IRDA faulty ?

Last post by SirExie - December 12, 2025, 01:48:27 PM

Just a follow up - I ended up getting an old Gopro Session camera and rigging it up to watch the transmit LED, and it DOES show the LED blinking.

It may not be a super scientific test, but I hope it confirms the hardware is ok and as LubOlimex pointed out, it's just the code.

I'm using ESPHome and I might just be struggling to get it to support Arlec signalling, which I'm guessing is Whynter from the earlier test which it determined from the Arduino-IRremote library.

#10

ARDUINO / Re: BC66 NB-IoT Module (DevKiT...

Last post by LubOlimex - December 11, 2025, 01:13:06 PM

Maybe try this, refer to the comments in the README files: https://github.com/OLIMEX/NB-IoT/tree/master/SOFTWARE/AT_restore_tool