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Sega Genesis build questions



  • Is it OK to use an extension cable for power? To fit it in a genesis case better. I know if you have wrong cables it doesn't get enough power so wanted to check. Also is it fine to use the sega original buttons such as power switch reset and the original led? Also do I need to add a resistor to the led? Thanks.

    I'm using a rasperry pi 3 b with retropie 4.4 build. Also the sega genesis is one of the old large ones. 1601 I think.



  • Unlike HDMI cables, power cable quality matters more. Power wires with crappy metals will generate less consistent power and increased waste heat. Length of cable doesn't tend to matter as much for power supply. So, I would think a high quality short extension would be fine. I have used a decent quality switched extension on my Pi without issue.

    As for your resistor question, I'm afraid somebody with more knowledge will have help you. I can complete such projects with some guidance and elbo grease, but I'm happy if my spastic fingers aren't soldered to the board when I'm done.



  • @orehruoy Take a look on the Mausberry with use your own switch setup.
    This is are brilliant devices and rock solid ... It's also possible to solder power LED to it (so you don't have to mess around with your resistors). I would tend to the 2-spring header version, costs are 18$ for this.



  • From what I've read I can do it without buying anything extra like the mausberry. Today I'm going to desolate the original switch and see if I can get it working with some shutdown scripts that have been posted.



  • I replaced the switches inside with these, had to trim the megadrive buttons a little, but was easier than reusing the original switches.

    Careful use of hot glue holds them in place

    0_1531673657483_generic-oem-switches-mini-microswitch-spdt-offset-lever-2-pack-27026327566_x700.jpg



  • @orehruoy No you can't. Don't rely on things posted on youtube. There will never be a real "poweroff" .... it's more like a deep sleep or standbymode.

    If you are interested in the powerbutton method (without extra devices) you can use the Multi Switch Shutdown Script with the --generic command.
    Then you can set your Pie into deepsleep mode and do proper shutdowns. But I think it's worth the money for a real power off device, mausberry, on/off shim, powerblock or other devices.... the on/off shim for ex. costs just 7$ or 8$



  • @cyperghost I can vouch for that. I use a PowerBlock to power off my Pi. I have one of the 5V lines on the Pi connected to a relay which powers off the monitor, amplifier etc on my cabinet when it goes to 0V. Without a real shutdown like thePowerblock etc, the relay doesn’t work as the 5V line stays high, ie the Pi is really “resting” not powered down.



  • Anyone know how all the 3 prong on the original genesis power switch are used?



  • @orehruoy
    Also can I test it on a breadboard and not ruin my pi. Or if it's hooked up wrong can I fry my pi?



  • @douga Yes that's the point. We speak of a "real" shutdown. AFAIK all devices that are connected to power rail (fans, external HDDs, LEDs...) did not poweroff without a dedicated device.

    All in all it's the decision of the thread starter but I don't want to push him in a direction ;)

    Personally the connection of a switch just connected to GPIO3 is a fair trade of costs and reliability. If you press the button the Pie will powerdown (Multi Switch Script strongly recommended!!!) and you press the button again the Pie will restart. But it's more a "hack" than a real option (IMHO!!!! (; !!!).

    @OrehRuoy Just a try to push you in a real poweroff option -- PIMORINI ONOFF SHIM

    Also can I test it on a breadboard and not ruin my pi. Or if it's hooked up wrong can I fry my pi?

    No not likely. If you try to get 5V on a 3,3V GPIO input then it might happen to get a fried GPIO input but all in all the Pie is robust for errors ;)



  • Maybe someone could help some with this...

    I took the original genesis switch out. It has 3 pins. I'm trying to figure out how it works. I am using this guide someone posted to try to figure it out... link text

    I have it setup to a breadboard. I have one pin set to a GPIO pin set as an output driven HIGH. I have the other 2 pins set to inputs. I also have 2 resistors. 1 running from each input to ground as the guy says on that link.
    I then made a script to test what the 2 inputs are reading. The problem is no matter which way I set the switch (left or right) they both are always reading high. What am I doing wrong? Does this mean the switch isn't working? or something else?



  • ok so I messed around a bit and got some more information.

    When the output which is always set HIGH is in the middle. The inputs change as follows when I go left or right.
    HIGH - LOW
    LOW - HIGH
    So they both change each time.

    When the constant output is placed on either side pin only the middle pin changes each time.

    So my guess is the middle pin connects to either the left or right pin depending on which way the switch is.

    How would I permamently set this up to control something say like a LED? Would I keep it how it is with one pin being output always high and the other 2 being inputs that change. And then a script to read the state and change accordingly.

    I want it as a permanent thing that the switch will turn on or off the system along with a led. I know theres a script already but I doubt it uses 3 pins. Also I do know its not a correct power off but the best I can do.



  • In case anyone else tries to use a genesis' original switch... middle connects to left or right depending which way the switch is. So you can connect middle to a gpio and one side pin to ground and it will work.



  • @orehruoy I think what you might of had problems with is the shutdown type button you use with the shutdown script is a single press sprung button to inturpt the signal/make a signal. ( squid button)

    Sounds like the mega drive button is a switch which is why it's changing around each time.



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