Thursday, 24 December 2015

Day 24 - Atari ST PC with intel i7

This is day 24 of the Advent Calendar of USB keyboards. Not Ruud Gullit sitting on a shed as predicted, but an Atari ST.
But this is no ordinary Atari ST. It has one of these inside.
Yes, that's an i7 4790K. This is going to take a while, so are you sitting comfortably? Well, it all started with a request for an Atari ST USB keyboard kit, and turned into quite a project. The owner asked if I could install a PC inside the ST, sure not a problem.
He sent me the donor ST and the bits to go inside. The i7 was a little gruntier than I was expecting (atom, Raspberry Pi, the NUC I used on the 800XL PC etc.).There were two main issues to think about here, power and heat.
The Atari ST has an internal power supply, that wouldn't be powerful enough for the new purpose, but it would be good to keep the mains input and power switch, and keep everything internal.
The initial thinking was to use a 12V power brick and something like a Pico PSU which plugs into an ATX connector and just requires a DC input. They only went up to 120W, and the owner was thinking they would need more. (processor TDP=85W, plus RAM, SSD, USB peripherals etc.)
We settled on a miniITX board that had a built in DC-DC and only required a single 19V DC input from a laptop power brick. This is the Asus H81T. All the connectors are along one side and not very high, and it looked like they would line up perfectly with the three D connector slots on the ST case.
There was one problem with that, it left the CPU under the keyboard, so there wouldn't be enough height for a cooler, especially one for an i7.
I did look at a few options, including using an old after market GPU heatsink, bent around to fit on the processor, but it wasn't really going to be viable.
Rotating it around, in both positions where there was sufficient height for the stock intel fan, all those connectors faced inwards. Not ideal, but when it came down to it, not many of those would actually be required. In the end, only the DVI out needed to be extended to the rear panel.
Time to put it all together. I rewired the mains input to feed a 200W laptop power brick, that should be enough power. The motherboard manual was very vague on power requirements, I only knew it was 19V as that was the label on the silkscreen, no actual statement of requirements. In testing, it didn't draw more than 60W, so that should be more than enough overhead.
I left the cable full length, so it could be replaced at a later date with another standard model. The connector on the end was a standard 2.5mm DC jack, so I made up a short lead to connect to the 2 pin header on the motherboard.
Under the power supply plate, I fitted two USB sockets, wired to the internal USB header on the mainboard.
The DVI connection was extended to the rear panel using a short cable, the shortest I could find that would reach. This was DVI-I, so a VGA adapter could still be used if needed.
On the left there, you can see the USB keyboard controller, wired to a single USB header on the mainboard with a short USB lead.
This connects to the Atari ST keyboard with a short cable with mating pins. It's been quite a 3D spacial puzzle fitting all this stuff in, but I like a challenge.
One of the reasons it was easy to go with rotating the board is the audio outputs on the mainboard were not being used. The owner had supplied a USB audio device. This has 4 phono plug for the inputs and outputs, but he wanted two 1/4" jacks, so I made up short leads for those and fitted the sockets on the side of the case.
I kept the original USB lead and plugged it into one of the spare USB ports on the board. Also plugged in there is a USB MIDI adapter.
This originally had 5 pin DIN plugs on to connect directly to an instrument. The ST originally had two 5 pin DIN sockets on the side, so I've rewired the USB MIDI adapter to sockets where the originals were.
The RAM and mSATA SSD are mounted on the mainboard, so no external drives to connect. A DVD-RW drive was requested, but I just couldn't find a space to squeeze it in.
I would normally have added quite a bit of hot melt glue to ensure it all holds in place, but the owner wants to strip it down when they get it and spray it black.
The processor is under the vents on the top of the case, and the side of the case was already cut out to fit a larger floppy drive, so there should be reasonable airflow. The modern i7 processors are a lot more efficient and run far cooler than those of the past. Compare the stock cooler here to the massive Noctua NHD-14 cooler on my old i7 (I've still got that somewhere, anyone want to buy an i7 950 for some old school overclocking?)
Are there it is, an Atari 520STFM running Windows 10, with a little help from an intel i7.
This is the last day of the Advent Calendar of USB keyboards, hope you've made it to the end. Thank you to those that have stuck with me. Time for a bit of a rest now; normal service will resume in the new year.

A new dedicated version of the Atari ST USB keyboard controller  used in this build is available from my Tindie Store.

Wednesday, 23 December 2015

Day 23 - VIC20 USB keyboard with USB hub

This is day 23 of the Advent Calendar of USB keyboards. Today, a Commodore VIC20 USB keyboard with USB hub.
These keyboards are all built to order, so I'm happy to take requests for changes. On this occasion, I was asked if I could fit a USB hub in the side (instead of USB joystick ports).
No problem. It took a while to find a suitable USB hub with the right spacing between ports, but I found a nice 4 port one. The metalwork is actually from a Commodore 64, as the VIC20 only had one  joystick port.
This was fitted inside and hot melt glued in place. Three ports on the outside (one blocked by the metalwork), and one inside for the USB keyboard itself. Leaving a single USB lead from the back of the case.
In use, just plug your USB devices into the side of the keyboard.

Tune in tomorrow to open the final window on the Advent Calendar of USB keyboards. Will it be Ruud Gullit sitting on a shed?

Tuesday, 22 December 2015

Day 22 - TRS80 Model 4 USB Keyboard

This is day 22 of the Advent Calendar of USB keyboards. Today, a TRS80 Model 4 USB keyboard conversion. I was sent this TRS80 Model 4 keyboard by someone who was part way through a case mod project on their TRS80, and wanted the keyboard converted into a USB keyboard.
The TRS80s with built in screens don't tend to survive well when shipped, and often the monitor mountings will snap off and the loose tube inside the chassis doesn't survive well. Hence I imagine the owner chose to start again. The keyboard was therefore untested, so the first step was to clean it up.
One of the keys (Clear) wasn't moving, and it looked like the key had snapped off at some point and been glued back on. It seems the glue had seeped down into the switch and locked the whole thing up, so I had to replace it.
The TRS80 used all individual mechanical keyswitches, but I didn't have an exact match to hand. It turns out the size is still standard today, and a Cherry MX Black switch fitted fine. The cross at the top was slightly smaller, but the keycaps was full of cyanoacrylate anyway, so I just cleared a suitable amount to fit snugly.
The pinout was different, but it was raised a bit higher, so I was about to wire it in between the metal frame and the PCB. Sorry, the picture isn't very clear, the two pins are the bottom of the Cherry switch, which doesn't reach the PCB, and the green wires are connected to the pads below.
The feel was slightly different, but as it was an ancillary key, this wasn't too noticeable. Had it been one of the more letters or numbers, I would have swapped it with one of the individual keys anyway.
With the key fixed, I was able to look at reading the keyboard. The connector used was a dual row 0.1" header, so a suitable connector was found and fitted to the USB keyboard controller. The keyboard plugged into this and the keyboard was mapped, a simple 8x8 matrix.
There was one extra key, the square orange power button. Although it looks like it should illuminate, it is just a push switch.
That's all reassembled and posted back to the owner, to continue their project.

Tune in tomorrow to open another window on the Advent Calendar of USB keyboards.

Monday, 21 December 2015

Day 21 - Atari ST USB keyboard kit

This is day 21 of the Advent Calendar of USB keyboards. Today, an Atari ST USB keyboard conversion kit.
I've been asked to build a few of these or assist with conversion projects on Atari STs. The conversion is easier than something like the Amiga 500, as it uses a standard serial protocol, albeit at the slightly usual baud rate of 7812.5.
The serial cable from the keyboard is unplugged from the ST and plugged into the lead from the USB keyboard controller. The cable is polarised to connect only one way.
The USB keyboard controller is mounted to the case at an appropriate position, either with the USB socket facing outwards, for USB keyboard use, or mounted inside if you are adding a computer of some description.
Most Atari ST keyboards includes two 9 way D joystick ports which can be accessed from the underside of the Atari. I understand the early smaller 520ST with no internal power supply or floppy drive has a different arrangement, but I have not been able to test this controller with one of those.
These will appear as USB joysticks alongside the USB keyboard, so you can use original Atari / Commodore joysticks.
The Atari ST USB keyboard conversion kit consists of the controller board, mountings and USB cable.

Tune in tomorrow to open another window on the Advent Calendar of USB keyboards.

A new dedicated version of the Atari ST USB keyboard controller is available from my Tindie Store.

Sunday, 20 December 2015

Day 20 - ZX Spectrum Pi Zero Revised

This is day 20 of the Advent Calendar of USB keyboards. Today, another ZX Spectrum Pi Zero, this time, the buyer asked, could they have access to the microSD card without opening the case?
Certainly, it now sits in the opening between the MIC and EAR sockets.
And still have USB and 9 way D joystick? Yes, no problem.
To do this, it was a case of rotating the Raspberry Pi Zero. This microSD socket isn't as nice as the usual one on the Raspberry Pi, it doesn't click and latch, but you can slide it in and out.
The wiring inside is revised slightly as the HDMI socket was in the way of the microUSB connectors.
The USB hub is now wired direct to 5V from the DC-DC board - I designed that with two 5V outputs for this configuration.
The 5V in and the USB D+ and D- are wired direct to the pads on the bottom of the Pi Zero.
As before, the two internal USB ports are for the USB keyboard on the lid and the USB joystick. Two USB ports are available externally.

I will be adding this as an option to the ZX Spectrum USB keyboard with Pi in my Etsy store, if you wish to order this version now, just let me know in the order comments.

Tune in tomorrow to open another window on the Advent Calendar of USB keyboards.