Hardware mod, tribute to the M4 board ;)

[dxs]

Hi there!


Just wanted to show off my latest hardware job, involving the great M4 board!


For this mod I used my spare 6128, which was perfectly fine, apart from a dead (and non fixable) floppy drive. I have no spare drive, and I don't like the idea of "Goteking" it which changes the computer look and feel. In my opinion the M4 superseeds it as I don't need the ability to read protected floppy images, especially since a great cracked games pack was released (check M4 thread for that).
So the goal was to internally mount my M4 inside this CPC, and re-use the floppy drive (a small part of it actually )


This is the final look of the modded CPC... impossible to distinguish from a standard one, as I also don't like "butcher like" mods:





Now the inside, showing the M4 mounted between the mainboard and floppy drive:





I soldered the 50P cable to the Centronics holes nearby the expansion port:





The only mod to the case are two holes for M3 screws to mount the M4:





I soldered some additional wires on the M4: the "SD activity" LED, and the reset button:





I modded the remains of the floppy drive by having the front LED wired to some pins of the original 34P back connector. A switch was epoxied inside so that it gets activated when the "eject" button of the drive is pushed, the connections for the switch are also brought on the 34P connector.
So the front face of the drive is unchanged:





and the led now indicated SD operations on the M4, the eject button is now the missing reset switch for the CPC!


Now let's wait to see if a WiFi based browser for the SD card becomes available, otherwise it would be possible to bring the SD card port on the front face of the floppy drive, to allow easy removal and PC/CPC transfer.

[Bryce]

Nice work. Just out of interest, what was broken on the 3in drive that made it unfixable?

Bryce.

[Duke]

Great work, looks very good

For the microsd, you could use something like this, to easily bring it somewhere accessible:
60cm TF to Micro SD Card Flex Extension Cable Extender Adapter Reader Car GPS |

[Bryce]

Great work, looks very good

For the microsd, you could use something like this, to easily bring it somewhere accessible:
60cm TF to Micro SD Card Flex Extension Cable Extender Adapter Reader Car GPS |

Those extenders can be a real pain in the arse. They work about 50% of the time.

Bryce.

[TotO]

Those extenders can be a real pain in the arse. They work about 50% of the time.

I disagree... They not work about 50% of the time! 

[CraigsBar]

Are the full size sd card ones any more reliable?
I has hoping to relocate the SD card slot in my HxC for my custom Amiga 600 with one.

Craig

[Bryce]

I disagree... They not work about 50% of the time! 

So is this glass half full or half empty?

[attach=2]

Bryce.

@Craigsbar: Nope, they are all pretty unreliable due to the fact that SDCards use SPI to send/recieve data. This bus system is quite sensitive and adding long (and unscreened) lengths of wire to the system can render them unusable.

[dxs]

On Arduino stuff, SPI trouble started at around 20cm cable length on my last project.
If I mount the remote SD port (I'll go for the SD instead of micro SD are they're easier to handle) the cable will be shorted as much as possible, and we'll see if that works or not. The shortest easily available ones are about 20 inches. The µSD port of the M4 is quite close to the drive face so not much length is actually needed.
(Btw @Bryce the drive was unrepairable because... well *years ago* I borrowed a bunch of parts (rods, motors...) for other projects... and even before it no longer read disks and that was not the belt)


But obviously a web based file browser would be much better, that I can't code unfortunately.

[TotO]

So is this glass half full or half empty?

W/o opinion! 

[Joseman]

Hi there!


Just wanted to show off my latest hardware job, involving the great M4 board!

Hi

I'm interested in this mod, as i will do the same in a short period of time.

one question:  how about the wifi signal strength with the M4 inside the cpc?

[SRS]

So is this glass half full or half empty?

[attach=2]

As long as it contains doppelkorn ...

@topic: nice mod. don't you need an extern antenna of some sort ? the german cpcs are very well shielded against radiation

[dxs]

Well how do I easily check the signal strength? All I can say is that it works fine at my place (consumer grade internet box with built-in wifi antenna). The french CPC has no shielding, so I don't think the signal is -that- reduced.

[Duke]

Well how do I easily check the signal strength? All I can say is that it works fine at my place (consumer grade internet box with built-in wifi antenna). The french CPC has no shielding, so I don't think the signal is -that- reduced.

With latest beta (1.0.9b8), when you type |netstat it will display a signal value too. Good signal is in range 0xC0 upwards. It may also be possible to check the signal strength in your router (atleast with dd-wrt I can see it).

[Joseman]

Hi again

About this mod, as i said i want to do the same mod for a friend of mine.

But i want to add a X-mem too.

the question is: how i interconnect the two pieces of hardware? simply making the same as @dxs but with 2-50pin cables or.. using only 1 cable with two terminals?

Any discrete components are needed to be added  for stability or good perfomance?

thanks!

[TotO]

It is the same expansion bus, so you can put two boards on the same ribbon cable.
But, take care about the lenght. If too long, you should have stability problems.

[dxs]

Tests regarding attenuation were carried.


Conditions are CPC one floor above wifi router, inside my house. The M4 is attached inside like shown on pictures in first post of this thread. Each time I walked away a few meters as the position of hands / body does change signal strength. Signal strength is given as printed by ùnetstat, inside a basic continuous loop.


Case closed: signal C3
Case opened at 90° (keyboard still attached): signal C9
Overall I observed attenuation of 5 or 6 units with closed case.


Btw @Duke I believe there's a bug somewhere as calling netstat repeatedly gives an error at some point, usually between 250-400 calls.

[TFM]

So is this glass half full or half empty?

[attach=2]

Bryce.

@Craigsbar: Nope, they are all pretty unreliable due to the fact that SDCards use SPI to send/recieve data. This bus system is quite sensitive and adding long (and unscreened) lengths of wire to the system can render them unusable.

Obviously it contains only 40% water and 60% air. So it's not half 

[Duke]

Tests regarding attenuation were carried.


Conditions are CPC one floor above wifi router, inside my house. The M4 is attached inside like shown on pictures in first post of this thread. Each time I walked away a few meters as the position of hands / body does change signal strength. Signal strength is given as printed by ùnetstat, inside a basic continuous loop.


Case closed: signal C3
Case opened at 90° (keyboard still attached): signal C9
Overall I observed attenuation of 5 or 6 units with closed case.


Btw @Duke I believe there's a bug somewhere as calling netstat repeatedly gives an error at some point, usually between 250-400 calls.

Not too bad I think. With the CPC about 1 meter from one router I get about 0xD0. And yes I am aware of the bug, hopefully I will get some time this weekend to fix it.

[pelrun]

@topic: nice mod. don't you need an extern antenna of some sort ? the german cpcs are very well shielded against radiation

You can get 400m range on an esp8266 with a bit of random rusty wire for an antenna. Gotta hand it to espressif, their RF front end is amazingly good. I've stuffed them inside devices with metal cases and still manage to get a solid connection. I wouldn't consider a CPC case to be shielded anywhere near that level.

[Prodatron]

Btw @Duke I believe there's a bug somewhere as calling netstat repeatedly gives an error at some point, usually between 250-400 calls.

This has been fixed today

Every signal strength >=#C0 is perfect. The total range seems to be #A0-#DF (below #A0 the signal is lost and I never get values higher than #DF).