Chip Station Portable – The game is on

Hey Chipsters, this post is about one of my current projects, the CSP – CHIP Station Portable.

Motivation

pocketchipI’m a big fan of the $9 C.H.I.P. – it’s a great module and I still can’t wrap my head around the $9 price tag. I’ve also bought two Pocket CHIPs but I’m frankly not the biggest fan. I’d rather use a single CHIP to build a small system and add the required components whenever they are required – e.g. add a screen via Tzatziffy  to build a small picture-frame.

Looking at the official pocket chip page gives me the impression that Pocket CHIP was made as a Gameboy replacement, but I’m still not convinced that the keyboard can be used for gaming. It’s too clicky, too hard to push .. simply not the right gadget for me. So the big question: How can I used the super cool CHIP for some gambling around, but have decent buttons and a nice form factor?

My first approach was to mill a custom wooden case with a screen and some buttons. But this has been done way too often by the game industry to do it once more. There are Sony, Nintendo, SEGA (only to name a few) who invested probably millions and had professional development teams, designer and usability tester to come up with a nice housing. So re-using an existing housing would make way more sense. There were already Gameboy and GBA thread running in the forum and I didn’t want to steal a project from another chipsters, so I’ve searched on.

The SONY PSPimg_20161105_150241
seems to be a fit-for-purpose gadget:

  • 4.3″ screen (same resolution as Pocket CHIP)
  • integrated 3.6V battery
  • 5V charging system
  • many gaming friendly buttons (4 left+4 right+7 below screen + even 2 shoulder buttons + power = 18)
  • absolute stunning design and perfect position of keys and screen layout in my opinion
  • widely available on eBay for decent prices $20-$30 (display alone: $20)
  • enough room inside the housing for modifications

What has been done by others

I’ve googled a bit a found pretty quickly that it has already been investigated by a page called othermod. The admin has done a absolute amazing job taking the PSP apart and also documented every step which gave me a head-start. The main tasks (from my point of view):

  1. Add lipo charger / discharge and battery measurement circuit
  2. Add audio amplifier
  3. Add external micro sd slot
  4. Add power on circuit
  5. Add display driver fpga (wow!)
  6. Add batteries
  7. Connecting the PSP buttons to the rpi

WOW! Thats an amazing amount of work and cost – the display driver alone cost 2x the money of CHIP and the all in one board is targeted at $80 and probably worth every penny (thats for the modification, you still need a (mostly) working PSP). The work to connect all the flat band cables must have taken weeks!

PSP and CHIP:

Lets see how this would work out with CHIP:

  1. Add lipo charger / discharge and battery measurement circuit on board on chip
  2. Add audio amplifier – yep that’s needed as well
  3. Add external micro sd slot needed not needed (but should be added)
  4. Add power on circuit on board on chip – might need some scripts to control the PSP LEDs
  5. Add display driver fpga (95%) on board on chip
  6. Add batteries reuse of PSP battery?
  7. Connecting the PSP buttons to the rpi

The amp isn’t expensive, same for the SD slot. CHIP has an parallel LCD interface that should more-or-less work with the display, so we only need the DC/DC part (we have to convert 5V to ~23V to drive the back-light, but I gained quite a bit of experience with the Tzatziffy) and we have to find a way to connect to all those nice buttons, battery, screen etc to CHIP.

Display

Alright, first step was to get a used PSP .. I’ve bought one for ~$25 (shipped) which had a bad UMD drive (perfect for me). I took it all apart (pretty much following this teardown guide). I’ve used one of my previously developed Tzatziffy boards to connect to the 40 pin zif cable .. and the display stayed black…  It took a day to find the root-cause which was simply an inverse polarity of the synchronization signals (didn’t read the datasheet correct). So after a small modification:

Here we go, CHIP + PSP display, without expensive FPGA board. This was more like a proof of concept, soldered with 20 free wires and an external power supply. The image was crystal clear but slightly shifted to the right (that issue is now fixed by using another driver).

Buttons

The next big line item were the reuse of the buttons. The hardware part of it was easy peasy thanks to the documentation on othermod

PSP Pinout

(image copied all credit to othermod)

I’ve search for a pin extender that would be compatible with CHIPs OS to avoid a custom kernel an found support for the PCA9555, single interrupt 16pin extender and connected this extender with some community help to act as a keyboard. So pushing the keys will make them act as regular keyboard inputs. This helps a lot, especially with emulators without gamepad support.

Create the replacement PCB

The real work was to get all the connector, the DC/DC circuit, the amp, the SD and C.H.I.P. on a single PCB that can be installed inside the PSP. I’ve asked othermod if I could get the outline, but unfortunately he replied that he isn’t ready to share his work – which I totally understand!

I’ve screwed the PSP to my CNC and measured all position by simply directing the drill to the center and write down the position from the screen. I’ve also cut a preliminary rough layout to see if the connector would end up in the right position.

After some modification I had a design for the first prototype to see if it fits as shown above, but the professionally made boards (see below) looked a lot better

The board is automatically identified by CHIPs OS and the driver for display, SD and the fake keyboard are loaded. The display runs of the onboard battery as well as CHIP does. SD card and Speaker .. all running fine.

I’ve cut the backdoor 51mm wide, instead of 41mm … oh well 🙂

And here is what this is all about, cable free, all keys working, including sound: (and yes, I’m not very good at Super Mario anymore :] )

Battery, speaker and charger input

The CSP is almost solder-free but only almost. The battery has to be connected to the board and I didn’t spend the time to find the right (probably SONY internal) battery connector, instead I’ve simply soldered two wires to the battery. The same applies to the speaker and the 5V charging cable. But it’s super easy to strip the cable and connect them to the board.

Software installation

Using the CSP doesn’t require any modification of CHIP OS. Its just a matter of loading the correct driver. This is achieved  by following the NTC guideline for DIPs (link). The installation process is a simple three stepp process. First make sure that git is installed:

sudo apt update
sudo apt install git -y

Second step is to clone the repository:

cd /opt/
sudo git clone https://github.com/KoljaWindeler/CHIP_STATION_PORTABLE.git

Third and last step is to call the installer, which will copy all required files

sudo /opt/CHIP_STATION_PORTABLE/overlay/install.sh

Reboot CHIP and it will recognize the display, SD slot and the buttons (as keyboard input).

Software goodies

I’ve added a script which is in big parts copied from https://raw.githubusercontent.com/fordsfords/blink/gh-pages/blink.sh to the respository.
It will

  • Monitor the battery and start blinking the power LED if the battery is below 15%
  • Shutdown the CHIP if the battery is below 5%
  • Starting blinking with the charge battery as long as the battery is charging
  • Turn the charge LED solid on as soon as the battery is fully charged
  • Shut CHIP gracefully down if the PSP power button was pushed

To run the script simply start:

sudo /opt/CHIP_STATION_PORTABLE/scripts/blink.sh

Hack the Hack

If you feel like modifying the Chip Station Portable – DIP you might need some info about which pins are already used and which are still available.

hdd_csp_v1

Problems and issues

I’ve tried to make this as user friendly as possible, but after all this is a hardware hack. The PSP was never meant to carry a C.H.I.P. and some minor modification are required.

  1. The metal frame of the PSP display has two hooks which needs to be removed, to make space for the pcb:
  2. It is complicated to remove the insulation of the speaker wire, I’d recommend to cut the connector to get to the part of the wire that has already been stripped.
  3. The battery isn’t quite compatible or mine is bad .. the charge indicator is always “loading” and never reaches “fully charged”.
    And even when the battery is fully discharged and definitively charging: The charge current  always shows: 0.0mA

Are you interested? I’ll probably build another CSPs on the weekend and can make some documentation for the hack. Just leave me a comment. I’m also thinking about selling the kit, but need to know how many would be interested. Target price might be ($35-ish) for the board with all connectors (you still need your own PSP) but really dramatically depends on the demand.



Build protocol for version 2

Step 1, remove everything from your PSP, remove every screw and every electronic board until you’ve a PSP as shown below.

001

Step 2, prepare the battery, the speaker and charge connectors

Step 3, add some solder to all PCB pads and solder the speaker and charger to the PCB

Step 4, solder the battery to the PCB, and UGLY: add two connectors to the display power circuit

Step 5, modify the frame a little bit ..

Step 6, connect the ZIF cable, align the PCB and crew the frame in. Make sure the d-pad is clicked into the frame.

Step 7, connect the display, and solder the display power to the board UGLY

Step 8, connect CHIP see if it boots and if so, connect all the outer shell parts

Step 9, if you can and want: Mill a 41x62mm cutout in the back. Now: fire up some games

Done 🙂

 

17 Comments

  1. Hay! If you need to re-home your PocketCHIP’s I would love to have 2 more. I use mine to play Multiplayer Descent. 4 Players is the max number supported and I have 2 PocketCHIP’s so 2 more would suit me right down to the ground. The $20 increse in price killed my ambition to buy 2 more right away – but I still think I’m gonna get them some day. I wan’t to have that portable LAN party rig and ready to travel.

  2. This is an awesome project, though I had a somewhat easier, though less compact solution with the pocketchip: buy a $25 bluetooth gamepad on amazon, that has all the same button layout as the vita.

  3. Wow! Again an amazing work! I’m becoming your fan, dude!

    I’m interested in it! In fact I bought my CHIP during the kikstarter time impulsively. Don’t planned any use with it.

  4. Definitely interested, but which model PSP would that be for?
    Also of consideration would be whether the thumbstick can be made to work, without further hardware modification. I’m happy hacking software, but hardware would be more complicated 😉

    • It’s for the PSP-1000 since it’s the only model that has a compatible display. As far as I know, making the thumbstick work (which would be absolutely awesome, I agree!) does require additional hardware, since it needs an analog input which, afaik, the chip doesn’t have. But I think it would fit on the current board and wouldn’t add too much to the costs, so maybe Kolja can look into it?

    • you’re right, psp-1000, analog joystick not used. Honestly: Its unlikely that I’ll work on it as I don’t like the joystick and it would be a lot modification required … one would need an external adc and some driver interface and I highly doubt that there is support for an analog joystick via adc in common emulators. Sry.
      JKW

  5. I’d possibly pay $25 plus some bananas for this board!

    I’ve got a PSP lying around doing nothing (don’t have a charger for it)

  6. What’s your ETA on having some boards (CSP) ready for sale – I’ll probably grab 2 – do you need some bananas for upfront investment? Put me down for two please.

    Regards,

    Dan / Outlaw

  7. I’ve already torn my psp appart in hopes that someone would mod one for emulators. I thought that the rasberrypi community would come up with something first but they kept saying “it’s not possible”. Glad I bought chip and have been waiting for something to use it on. I’d totally buy a board, I’m already half way there! Please do post more info when you have ideas of how you want to do this. I’ll check back weekly

    • I will post updates as soon as I have all parts available, which will take a while. I’ve ordered the parts for the first board at mouser and their prices are just too high for a production run.
      Jkw

  8. +1 for interested in buying this. I have the Pocket CHIP and not sure how much more modification I’d need to make that work, but I am NOT a hardware guy and I’d easily pay to get your mod…

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