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Forum Index : Microcontroller and PC projects : Add a remote control to a Harman Kardon HK6350R amplifier.
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Marcel27 Regular Member  Joined: 13/08/2024 Location: NetherlandsPosts: 53 |
I think you are right with the modulated version.  The new circuitry....  If you use AI, you lose your mind. |
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Mixtel90 Guru  Joined: 05/10/2019 Location: United KingdomPosts: 6761 |
I've not been able to find a data sheet on that IR receiver. It's probably a good idea to change it for a more modern one. Just make sure your remote works with it first though or you'll be sad. :) Looks like you could do that with a RP2040-Zero. There's not a lot of IO. A bit of a pain to surface mount though. A TSOP28328 IR receiver would run from 3V3 and you could lose a transistor. It does the 38kHz decoding too. . Edited 2024-10-31 03:07 by Mixtel90 Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Marcel27 Regular Member Joined: 13/08/2024 Location: NetherlandsPosts: 53 |
Hi Mick, There is indeed no data on the SBX1619-52. My remote works with the SBX1619-52 but not all codes/buttons are resolved. So I'm using the TFMS5360, all buttons produces a code. This sensor handles the carrier also. Good idea to use a 3.3V type sensor, although the 3.3V types are cheap I have a few 5V types lying around and the transistors also. These are the cheapest Pico's €3.95, the RP2040-Zero is much more expensive.  Your idea to create a new pcb is great. I looked around for some software for pcb-design and found several packages. Two of them are my favorite: Sprint layout and KiCad. I read a lot of negative feedback about KiCad, that it doesn't work intuitively and other things. I have no experience with any software package, except EasyEDA and I never had a printed circuit board made there because it was way too expensive. Now I'm learning KiCad and and so far everything is going well. Maybe I'll get to a point where I start cursing.  Sprint Layout 6.0 costs €50 and I do not know if I'm going use this software on a regular basis to justify the expense. Next step is to create a board for de HK6350R with a Pico on it and some obsolete old stuff.  If you use AI, you lose your mind. |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6761 |
The RP2040-Zeros that I got from AE were nothing like that. Currently £1.42+vat, mid price. Not many dearer than that. You aren't stuck for space though. :) Looks like Sprint Layout has gone up in price. IIRC I only paid about £30. EasyEDA is the way to go for a free package now, I think, if you want "proper" PCB software. I fell out with KiCAD when I attempted to create new objects. I doubt if you'll find a PCB house cheaper than JLCPCB. If you can get the PCB size down to less than 100mm x 100mm you'll save a lot of money! You can have more than one design on the same board if you only separate them with a silkscreen line and saw them yourself. By the way, using a transistor between the IR receiver and the Pico is inverting the signal. That's fine if you can handle it in the Pico's software but if you can't then it may not work. . Edited 2024-10-31 04:46 by Mixtel90 Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2129 |
Part of the issue of the old Sony IR receivers poor performance is their maximum sensitivity is at 40kHz, not the more common 38kHz. (Philips use 36kHz). Regarding level shifting a 5V sensor, they usually have an open collector output with an internal pullup (40kΩ is common) so all that is needed is a suitable pulldown resistor. Finding the value of the pulldown is easy as the output is idle high. 1) Before connecting to the Pico simply put a 82k from the output to ground and measure the voltage. If it is a bit high or low change the resistor to get it in the range 2.5 - 3.3V. 2) Or just add a Schottky diode from the output to 3.3V. |
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| Marcel27 Regular Member Joined: 13/08/2024 Location: NetherlandsPosts: 53 |
Woooha, I had my KiCad swearing moment when assigning a footprint of the RP Pico. But I did it. The next step is to find out where I can specify the dimensions, for the time being I was going around in circles. @Mixtel90: I did indeed find an RP2040 Zero for €5.00. As you already indicated, there is enough space on the PCB to place an RP Pico. Fortunately, I have not had to make any new objects yet. I am just having a little trouble finding the right component in the endless list with the right dimensions. So far I can keep the PCB within 100mm x 100mm. The wiring with the connector is long enough to be placed on the new location on the PCB. Yes, the signal is inverted because of the transistor, but strangely enough it works. I still have to check whether the transmit codes are also correct in the normal or inverted situation. phil99 also suggested to just use a pull down resistor on the output of the remote sensor or a Schottky diode to 3.3V. @phil99: thanks for the input, I'll test it. Thanks, both of you for the input.  If you use AI, you lose your mind. |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6761 |
I like phil's idea of the pull down resistor. Very simple and foolproof. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Marcel27 Regular Member Joined: 13/08/2024 Location: NetherlandsPosts: 53 |
The resistor pull down phil99 suggested is working. I'm using now the TFMS5360 from TEMIC (Telefunken 1996) an oldie from another amplifier. The datasheet tells me that it has an internal 100k resistor from output to 5V. An external resistor with a value of 180k does the job. The voltage at the output is 3,34V. Next step is to change the KiCad circuitry again and create a footprint for the sensor lying on it's back and looking to the frontside. Still need to find the board dimensions  Thanks, gentlemen. If you use AI, you lose your mind. |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6761 |
If you are considering surface mounting the Pico make sure you can still get the programming lead to it. If you aren't, make sure there is enough depth behind the front panel. :) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Marcel27 Regular Member Joined: 13/08/2024 Location: NetherlandsPosts: 53 |
 If you use AI, you lose your mind. |
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