how to determine IR remote codes for consumer audio amp - Page 1
Forum section: electronics / repair

author: hummusdude
author_rank: Regular Contributor
timestamp: January 02, 2022, 01:36:12 am
content: My Kenwood powered subwoofer is missing the remote and I'm wondering if there is a known way to figure out what binary sequence it uses. I have some transmitter LEDs and an arduino so I was thinking perhaps I could hack together a remote in order to access some of the functions that are otherwise unavailable. I have the schematic available if that helps.

author: sleemanj
author_rank: Super Contributor
timestamp: January 02, 2022, 01:54:01 am
content: http://www.remotecentral.com/cgi-bin/codes/kenwood/https://github.com/mkatzef/pronto-remote

author: hummusdude
author_rank: Regular Contributor
timestamp: January 02, 2022, 03:24:18 am
content: Wow...I feel like I hit the jackpot! I figured I would have to reverse engineer all of it. thanks for the links!

author: hummusdude
author_rank: Regular Contributor
timestamp: January 02, 2022, 04:30:08 am
content: Hmnn....so it doesn't appear as if my device is represented in the link. I found a pic online of the remote and the model number is RC-W0501. I've googled that number and I'm not finding anything. Perhaps it's too old.

author: JDubU
author_rank: Frequent Contributor
timestamp: January 02, 2022, 05:36:03 am
content: Don't know if this is legit:https://mandisshop.ie/en/Kenwood/1038072-82604-replacement-remote-control-for-Kenwood-RC-W0501.html

author: Peabody
author_rank: Super Contributor
timestamp: January 02, 2022, 06:03:34 am
content: Before buying a replacement remote, you might use your Arduino to try out the codes used by other Kenwood products to see if they might work. Typically a manufacturer will use the the same IR codes for everything. Just be sure you get your transmitter LED right up close to the Kenwood, and go for maybe 100mA through the LED. The original remote probably used more current than that.

author: hummusdude
author_rank: Regular Contributor
timestamp: January 02, 2022, 06:27:12 am
content: That was my suspicion. I don't think I will put any $ into this project. I'm more into the challenge of figuring it out anyway. Thanks for the input!

author: geggi1
author_rank: Frequent Contributor
timestamp: January 02, 2022, 10:51:10 am
content: Try the codes for a similar unit form Kenwood.Its common to reuse stuff likte this.

author: Peabody
author_rank: Super Contributor
timestamp: January 02, 2022, 05:18:03 pm
content: One other thing to watch out for is that IRremote.h, the Arduino library, had a major format shift beginning with version 3, and it's not clear the usual hex codes you see quoted still work in the new version, or if any sketches written for the older versions still work. I've actually had better luck using v2.8.0. The Arduino library manager wil let you pick the version to install.

author: m3vuv
author_rank: Super Contributor
timestamp: January 02, 2022, 11:01:04 pm
content: Is there not a smatphone app that can do this?

author: hummusdude
author_rank: Regular Contributor
timestamp: January 02, 2022, 11:06:36 pm
content: Pretty sure my phone doesn't have infrared capability. Does yours?

author: m3vuv
author_rank: Super Contributor
timestamp: January 02, 2022, 11:34:21 pm
content: Yes my phone does,its an old samsung galaxy s5,the s4 has ir tx too tho.there are apps on the playstore,install one then view your phone thru a digital camera,it will flash white on the camera if fitted.

author: sleemanj
author_rank: Super Contributor
timestamp: January 03, 2022, 12:30:31 am
content: I don't know why this has got stuck in my head, but I actually hacked togethor a script to decode those Kenwood pronto codes into NEC Device and Function bytes to see if there was any particular pattern (my script just assumes they are NEC but all the ones I looked at seemed to be).https://gist.github.com/sleemanj/c51dabfcff7ba73d454f27deb78c54f9If we look at the Power sequence for CD-224M it decodes with my script toCode:Device: 01101101Function: 10001001---And for the 405,Code:Device: 01101101Function: 10001001Identical---And for the DV-5900M,Code:Device: 01101101 but check complement 00110000 does not match: could be 11001111 maybe.Function: 11110011The function is different, but the device, even though the complement is unexpected, is the same.---But the KRV-8050Code:Device: 00011101Function: 10111001is completely different.---It might be worth tryingDevice: 01101101 and all the functions (0-255), but start with 10001001Function: 10001001 and all the devices (0-255)to see if you hit on a combination. If you can find the device code, then you only have 255 codes to test.