Problem with HLK-rm04 and LED control

Hello,

I'm not sure if I'm puting this issue in the right place, so sorry in advance if I'm wrong. The thing is that I've built a row of 3W LED dimmer controllable through wifi with the HLK-rm04 module and an Atmega328 standalone. Everything is working fine, but the LEDs aren't as smooth as I wish. There is a really fast blink (almost imperceptible but annoying once you notice it) with a stable period of almost 1 second. First I thought it was a PWM frequency issue, but increasing it doesn't make any big improvement.

Accidentally I disconnected the rm04 module and realised that without it the LEDs work perfectly, no blink at all and a really smooth light. I have already tried puting a 10uF capacitor between source and ground, but still nothing.

Does anyone know how can I isolate the wifi module so it doesn't interfere with the rest of the components?

Many thanks!

Accidentally I disconnected the rm04 module and realized that without it the LEDs work perfectly, no blink at all and a really smooth light. I have already tried putting a 10uF capacitor between source and ground, but still nothing.

Tel me, do you use the Arduino to supply out the RM04 unit? This unit take lot of power, maybe you should supply it with external power if it's the case.

Personally I use the base plate that come with it's own power source, 1 amp, to power the Arduino. So basically, I do the other way around.

Hi, thanks for your reply!

Well I'm using an external 12Vdc-3A power supply and until now, it was connected to a 5vdc regulator (L7805CV) to power the atmega and the rm04 module at the same time. Just now I added another regulator to power them separately and it has improved a lot. Maybe now I'm just being paranoid but I can still sense some blinking. Anyway it's for far as smooth as I wanted.

Now the only issue I can find is that the regulator is really hot (the one connected to the rm04 module). Checking the datasheet the rm04 shouldn't need more than 140mA, and acording to the L7805CV datasheet heat sinking is needed when they have to deliver over 1A output current. Any suggestions powering the module?

Thanks!

You will always sense some blinking, since it’s PWM. The PWM technology is different from the DAC technology, and if you are like me, you probably can see the neon blinking. :wink:

Any ways. As long that you will be using noise to power up your led, this will be true. Maybe you could use one of those module

http://www.aliexpress.com/item/3pcs-lot-PCF8591-AD-DA-Conversion-of-Analog-to-Digital-Digital-to-Analog-Converter-Module-Temperature/1145286682.html

give out 1 DAC and take in 4 ADC and they are simple to program. With these you can make a almost perfect sinus signal so it will also give you a very stable signal.

Checking the datasheet the rm04 shouldn't need more than 140mA, and acording to the L7805CV datasheet heat sinking is needed when they have to deliver over 1A output current. Any suggestions powering the module?

Heatsink.... ;) lol

So just to be sure…that overheating is normal supplying only 140mA?

Many thanks!

So just to be sure...that overheating is normal supplying only 140mA?

Probably not, but depending where you got the 7805, probably China right?, I would not be surprise that it does. Any way those unit, if I'm right, are flushing all the unused juice to the ground so it's pretty normal that it get kinda hot, but how hot is it? Have you tried another 7805, maybe it has a little defect. But what really matter after all, if it's not hooked on a battery, is it sending a steady 5volt at the output?

Tel me, have you tried to put OPENWRT on it? Do you plan to? And if you do, please tel me about your experience.

Hello,

I'm one step back from you...

Is the code that you are using available on the net. I have a couple of these modules and have not found any code that makes them work.

Thanks Tim

When you say code, do you mean code for arduino or openwrt?

For openwrt there is a wiki here:

http://wiki.openwrt.org/toh/hilink/hlk-rm04?s

and if you mean code for Arduino. Well as soon that i'm done coding for the TLG10ua03 module, i'm gonna start coding for this one

Hi,

Sorry I haven't used openwrt on it and for now I won't. I'm just using the default web interface to configure it and to connect to wifi in the cheapest way I've found.

I have a couple of these modules and have not found any code that makes them work.

I'm just sending strings over TCP to the module, and then with the arduino you only have to read/write through serial. What code are you trying to use? It's probably a configuration issue...does it respond to a ping at least?