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Forum Index : Microcontroller and PC projects : I2C keybvoard design for PicoMite family
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| matherp Guru  Joined: 11/12/2012 Location: United KingdomPosts: 9139 |
GBP 18 fully built by JLC. Just need to write the code for the STM32. 210.82 mm * 66.04 mm   Edited 2023-04-11 07:56 by matherp |
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thwill Guru Joined: 16/09/2019 Location: United KingdomPosts: 4047 |
ROFLOL, you're a "dangerous" man Peter. The price is about twice what I originally paid for my M5Stack i2c keyboards, though it is also bigger; is that STM32 semi-unobtainium ? Could an RP2040 (running MMBasic ?) do the job. Or am I making sh*t up because I'm too ignorant to know better ? Best wishes, Tom Edited 2023-04-11 09:03 by thwill Game*Mite, CMM2 Welcome Tape, Creaky old text adventures |
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| robert.rozee Guru Joined: 31/12/2012 Location: New ZealandPosts: 2350 |
been done years back, as i recall Grogster was involved, used a MX170 running MMbasic as the controller. total sales: approx zero. laying out the board is easy, the hard part is the plastics to turn those itty bitty buttons into usable flat keytops with labels on them. the plastics is always the hard part, no one has solved that one to date. here is the simplest solution: https://www.ebay.com/itm/313641188025 buy a replacement netbook keyboard from china for us$15 and just build an interface board. use either an arduino (atmega328p chip), or a pico board. design the software to be flexible enough to accept a number of different netbook keyboards, although those NAV51 keyboards have been around on ebay for over a decade now and likely will be for quite a few more years. cheers, rob :-) |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 9139 |
No, it is chosen because it is in stock at JLC and a "basic" part so minimum cost. All the parts are "basic" for cost reasons The GBP price of 36 for 2-off and includes shipping and VAT The actual cost per board is just under GBP9 I intend to design a 3D printable overlay to turn it into a "real" keyboard The problem with netbook keyboards is that there are no pinouts available, the pinout is probably not standardised, and they need a undefined FPC connector before you can even start to try and buzz them out to connect to a uP. After all that you can start to think about how to mount them in a usable way |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6812 |
I like. :) I like the two spiky sticky up finger piercers at the LH end too. ;) (swap them for right-angle ones?) I can see the 3D printer owners being in demand: "Hey, ..., How do you fancy swapping one of your keyboard overlays for one of my ready built keyboard PCBs?". :) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 9139 |
The headers were just to create the holes in the PCB. The 5-pin one is the ICSP header for debug/development. The 4-pin is the actual I2C and could be right angle on the bottom or flying lead - whatever |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6812 |
I thought it might be something like that. JLCPCB never cease to amaze me. After searching in vain for a UK supplier who would even consider producing a low quantity of bare PCBs at less than an extortionate price and less than many weeks delivery time they put our PCB business to shame. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| robert.rozee Guru Joined: 31/12/2012 Location: New ZealandPosts: 2350 |
1. the pinouts are DEFINITELY not standardized across different models, hence why you would need to first obtain a sample of the model you intend to use and buzz it out. this is not exactly rocket science, they are just a simple matrix with no components integrated into them. as i said before, the NAV51 keyboards have been around for OVER A DECADE and are still obtainable. 2. the FPC connectors come in about three different pitches. in a 'home built' environment you only need the right pitch and AT LEAST enough pins - it is easy enough to insert the FPC hard up against the pin 1 end of the connector and ignore the space left at the other end. in no way practical on a production line, but fine for 'home built'. use the 'lever locking' connectors, these are both ubiquitous and cheap. 3. mounting the keyboard is absolutely trivial! pick your housing, cut a rectangular hole in the top, and sit the keyboard in the hole. use a chunk of flat wood or similar solid material behind the keyboard to prevent it flexing. there is nothing simpler to mount, other than perhaps one of those self-adhesive 4x4 keyboards that you stick to a flat surface. the NAV51 is rectangular, obviously avoid any model that has a non-rectangular shape. these keyboards date from an era when they were designed to clip into a 'tray' opening in laptop, from the OUTSIDE. often memory upgrades and sometimes access to the HDD was via removing the keyboard, just like lifting the lid on a biscuit tin. 4. software-wise, as the keyboard is JUST a simple matrix, you could likely write the software in such a way they you don't even need to buzz out the keyboard first, but have the software interactively 'learn' the key placements through a configuration program that the user runs. instructions like "press Q to P keys in order" would suffice to map out most of the keys. cheers, rob :-) Edited 2023-04-11 19:47 by robert.rozee |
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Hans Senior Member  Joined: 18/10/2022 Location: CanadaPosts: 116 |
@matherp Nice KB Peter, you are one hell of a machine!  My preference would have been to have the RESET and BOOTTO buttons at the top of the KB, perhaps on the right side. Just a thought.  Hans ...  |
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9308 |
Yes, I did one using a cheap BT keyboard from ebay or AE. It was blue with white keys. I think it only cost $5 or something like that at the time. I gutted the KB BT interface, and replaced it with a 170, and this one outputted standard ASCII serial @ 9600 baud rather then I2C. The idea of doing it that way, was primarily cos you would get a nice professional looking keyboard, but still small-ish. I can't even find the photos I took now, it was years and years ago. I expect I could hunt out the thread, but as Rob said - zero sales.  I don't think I even bothered to keep the prototype, cos at the time, if a MM supported a KB, it would have been a PS2 one. I can't even really remember WHY I built the first one now, cos if you needed KB input, you could just use the MM+ series of chips that supported that natively, and at the time, the chips were plentiful. Smoke makes things work. When the smoke gets out, it stops! |
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