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Forum Index : Microcontroller and PC projects : Keyboard for Micromite Plus
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| Frank N. Furter Guru  Joined: 28/05/2012 Location: GermanyPosts: 946 |
@Grogster: It's not my credit with this chatpad - robert.rozee wrote in this thread about this little nice device... @TZAdvantage: It looks like the right one! Frank |
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9585 |
Guys, I bought this one on eBay. I think the first thing I will do, is experiment with a MM and and array, to transcode the relevant keypresses from the MS protocol, into serial. Something new to play around with. ;) IF the keypad wiring is a standard matrix, then I could employ the 6x6 matrix idea to it - this MM can go up to 8x8 matrix. But before we get too crazy, I will have a play with using the MS protocol - it is quite well documented by other people on the likes of this site. Smoke makes things work. When the smoke gets out, it stops! |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9585 |
Plasma was right!  
...not that I doubted him. Chinese eBay ChatPad: 
I am going to have a go at working out the matrix wiring, so that then we could just grind off the chip and it's protective black epoxy blob, and hook into the matrix directly, and couple to a nice MM controlled replacement.
Something else to play with. EDIT: I have been unable to get any kind of serial output from this unit at all. It is possible it is a factory dud, but no MM circuit sees any valid serial, and the logic analyser also sees not a thing. I have ripped all the wires off, and I will grind the chip out of the equation, so we just have a keyboard matrix, then I will design a dinky SSOP board to slide in there and interface with the matrix - so long as I can work out the matrix. I have been trying to find any info on the matrix used in the chatpad, but have so far found nothing. If anyone has any links..... Smoke makes things work. When the smoke gets out, it stops! |
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| robert.rozee Guru Joined: 31/12/2012 Location: New ZealandPosts: 2428 |
would it not be simpler to make a complete new PCB from scratch, so you end up just using the original mechanical components? how much would it cost to have a PCB that size made? i also wonder if something could be done with one of the cheap bluetooth keyboards out there - either re-engineered completely or picking off the data between the keyboard encoder and bluetooth transmitter: http://www.ebay.com/itm/181725549780 cheers, rob :-) |
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MicroBlocks Guru Joined: 12/05/2012 Location: ThailandPosts: 2209 |
Rob, that is thinking out of the box. :) Can also adapt the pcb to add a chip of your choice and have serial,i2c, bluetooth whatever you fancy. Then it is just a quick pcb swap. Sounds like a good idea. Microblocks. Build with logic. |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9585 |
@ Rob - now that is what I call thinking - nice one!  I will investigate that some more, as then you know exactly what is going on, and as you say, just reuse the rubber contact pad and it's housing. A much better idea then playing around with trying to decode the existing matrix.
I will investigate. @ TZA - Good idea too, I will take it under advisement. EDIT: Looking at the link Rob put up, I see there are many many choices of mini keyboard - way more then I thought there would be, so I have ordered a couple of cute blue ones to play with - these are available from various sellers in blue, black and white. Small Blue Keyboard Smoke makes things work. When the smoke gets out, it stops! |
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| MicroBlocks Guru Joined: 12/05/2012 Location: ThailandPosts: 2209 |
That blue one looks good. I ordered one too. If it has a bluetooth module it might be controlled through serial,and that can be captured and maybe used. Otherwise it is just using the matrix. Microblocks. Build with logic. |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9585 |
Yeah, I too was impressed with the little blue one. It's bigger then the chatpad, but smaller then a full-size keyboard, which I think is a good thing, as then the keys are not too fiddly. I see that the back panel just unscrews, so it should be nice and easy to get inside this keyboard, and see what we have. Smoke makes things work. When the smoke gets out, it stops! |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9585 |
UPDATE: Microchip do several modules, one of which the RN42 is a complete Bluetooth stack solution including HID support(Human Interface Device) for Bluetooth mice and keyboard supprt, and simple UART output - for the princley sum of $15 or so from Microchip Direct. I am still studying this device in more detail, but as well as supporting HID, it also supports several other Bluetooth profiles such as SPP, so it is an interesting module. Smoke makes things work. When the smoke gets out, it stops! |
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| MicroBlocks Guru Joined: 12/05/2012 Location: ThailandPosts: 2209 |
It is a pretty old one though with bluetooth 2, we already have bluetooth 4 and also the BLE which are more interesting for new project. There is one in development http://www.microchip.com/wwwproducts/Devices.aspx?product=BM70 One that is available now https://www.adafruit.com/products/1697 (Better price also). But i am not sure if they have been tested for compliance. Microchip doers have that so for a commercial product that can be very important. Microblocks. Build with logic. |
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| robert.rozee Guru Joined: 31/12/2012 Location: New ZealandPosts: 2428 |
bangood also sell them for a similar price. reading the feedback on bangood's website, some buyers have complained that the back plate is just thin galvanized steel sheet. but then, if you are 'reworking' the keyboard the back plate could at the same time be replaced with a piece of laser-cut 1/4" perspex. this would greatly increase rigidity and weight. "Scissor type keyboard, quick typing, good touch": with a bit of luck, it may turn out the keyboard is built like a laptop/netbook one, where the keyboard has a pair of FFC ribbons running to connectors on a very small PCB containing just the electronics. being small in area, this would be very cheap to replace. my thoughts are that serial out would be most useful, providing VT100 keyboard emulation, as this would interface with any of the micromite family. if my reading is correct, the micromite plus can accept input from both serial console RxD and PS2 keyboard at the same time. do simple "print" statements similarly go to both an attached colour LCD and out the serial console TxD line too? cheers, rob :-) |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9585 |
@ Rob: - I will check out the backplate when they get here. Kinda does depend on how brutal you plan to be with the thing, but I will post here about that. - As far as I know, the console commands on USB are echoed on the native serial terminal, and vise-versa, and this is all seamless and automatic. In any event, I will put up some photos once they arrive. Smoke makes things work. When the smoke gets out, it stops! |
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| paceman Guru Joined: 07/10/2011 Location: AustraliaPosts: 1329 |
I reckon these are the answer. |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9585 |
UPDATE: My little blue units arrived at last. Here are some shots: 
Rob is correct - the backplate on these things is about as flimsy as one of those tin oven dishes. Screws holding the back on are about 1mm in length, and one of the two units I got, had five screws missing, and one more fell out when unpacking, so we definetly need some sort of hardware improvement there.
On the plus side, the keyboard itself seems to be s standard looking matrix, and there are even nice little test pads on the PCB, so I can probe the matrix to find what key is where. I have had a look on the web for the HASKEY part number, but cannot find anything. Further down the ribbon, there is the marking: "PRIDE-K1311 VER:B", so I will also look for that too. It would be quite easy to grind and file a small slice of 3mm aluminium to replace the bottom, and give back the rigidity to the board as a whole. I think I would just use zinc or stainless countersunk machine screws from the top of the keyboard, and use small rubber feet to keep it off the table on the bottom - a work in progress... EDIT: Forum has squished these images a little, but you can see the gist of it. I have high-res close-up images if anyone wants to see them. Let me know if that is the case, and I can link to a ZIP file. EDIT: Control chip is AIROHA AB1112A, which directly interfaces to the matrix. Looking for datasheet - does not appear to be available from their site. Not sure the data sheet will be much help as far as the matrix is concerned, as this device has a PROGRAMMABLE matrix up to 8x18, so it could likely be just about anything. I am not going to waste too much time on datasheet searches - I plan to hook up one of WW's 44 pin MM modules an write a matrix scanning code, to allow me to decode the matrix. Smoke makes things work. When the smoke gets out, it stops! |
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Positron Newbie  Joined: 09/08/2015 Location: ArgentinaPosts: 15 |
grog & others: if you're still interested in the Chatpad matrix layout, I figured it out some time ago for a mini serial terminal that I built using and Arduino mini pro and a graphical LCD display. I can search my project files and publish a download link; just let me know. |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9585 |
Yes please. 
That would be very useful to have, as the chatpad is also still one of the units on the agenda. Smoke makes things work. When the smoke gets out, it stops! |
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| Frank N. Furter Guru Joined: 28/05/2012 Location: GermanyPosts: 946 |
Hi Positron, that would be very useful! 
Frank |
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bigmik Guru Joined: 20/06/2011 Location: AustraliaPosts: 2947 |
Hi Grogs, I believe this is the datasheet you want AB1112A Regards, Mick Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<< |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9585 |
...you crafty Australian.
Thanks, mate. Smoke makes things work. When the smoke gets out, it stops! |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9585 |
UPDATE: Here is a photo of the keyboard membrane once removed from the plastic case by drilling out the melted plastic locating dowels: 
The keys themselves, the rubber springs, the membrane and the black plastic backplate are all one unit, so it is not easy to remove them - I will leave well enough alone. I will remove the matching connector from the PCB, then hook up some link wires so I can run tests to establish which key is where. That done, I will design a PCB consisting of a MM(I think the 44 will have enough pins, failing that, the 64 MM+) to interface to the keyboard, and output serial. This will all be released on the forums, so others can copy from it, if they wish to. Code would not be the most efficent in the world, but other members would be free to develop better code for driving the thing, and perhaps even adding the VT100 commands to the serial stream - who knows. The latter would be extremely useful, as then this keyboard project could be directly connected to the MM console.Smoke makes things work. When the smoke gets out, it stops! |
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