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Forum Index : Microcontroller and PC projects : My little DREAM COMPUTER
| Author | Message | ||||
| Frank N. Furter Guru  Joined: 28/05/2012 Location: GermanyPosts: 828 |
I've always wanted to have a small, portable BASIC computer. Here it is now:    The device should be able to run for approx. 22 hours with the power bank shown. The current consumption is approx. 80-90mA@5V. The computer has three micro USB ports: - Keyboard (or hub) - power - PC via TTL-USB (it can also be supplied with power via this) I used an ILI9488 with touchscreen as the display. To do this, I had to insert a 1N4148 with a resistor in the MISO line, swap the series resistors in front of the card reader for 0R and set the solder jumper J1. It has a separate power switch for the USB power socket and the heartbeat LED has been led out. The internal LED was removed and the series resistor was increased from 470R to 4K7. The Würth 3mm LED (151033GS3000) still shines almost too brightly! Unfortunately, the LED is not on in all the pictures at the moment I pulled the trigger. A DS1307 RTC and a piezo buzzer are also built in. Unfortunately, the buzzer sound is very high and very quiet. The SD card holder is accessible from the outside. Today I received shortened card adapters - unfortunately they were squashed so much during transportation that they don't work properly (the internal contacts were pressed flat...) GP0 and GP1 are accessible via a 3.5mm stereo socket. I installed all this in a TEKO SR31.7 housing. The case was far too expensive at €14.71 and the screws supplied are too short!  Unfortunately, I have not found any other housing with these dimensions... It doesn't look so nice from the inside, but it works:   All in all, I'm very happy with my little DREAM COMPUTER at the moment!  Frank |
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| lizby Guru Joined: 17/05/2016 Location: United StatesPosts: 3150 |
Nice. I like it. Wireless USB keyboard makes a nice feature (if one doesn't expect to do too much typing on it). PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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| Bleep Guru Joined: 09/01/2022 Location: United KingdomPosts: 509 |
Hi Frank, Looks great :-) very nice portable, almost laptop computer. I've been thinking of making something similar myself, I'll have to get a move on now ;-) Regards Kevin. |
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thwill Guru Joined: 16/09/2019 Location: United KingdomPosts: 4038 |
Nice. In a similar vein I've dropped the cash for one of these: https://www.clockworkpi.com/product-page/devterm-kit-cm4-series which is why I've dusted off and started work on MMB4L again. This is of course a full Linux computer (Raspberry Pi 4 Compute Module) rather than "Boot to BASIC". 60 day wait time though, so fingers crossed as to whether I get anything for my dollar. Best wishes, Tom Game*Mite, CMM2 Welcome Tape, Creaky old text adventures |
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| Bleep Guru Joined: 09/01/2022 Location: United KingdomPosts: 509 |
Hi Frank, Just noticed the version of Solar System you are using is for a 320x240 display, if you prefer I attach one scaled for 480x320. If you haven't enabled backlight brightness, you will need to comment out all lines setting brightness. Regards Kevin. PS. what are your option settings? solarsys480x320.zip Edited 2024-03-01 03:51 by Bleep |
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| Frank N. Furter Guru Joined: 28/05/2012 Location: GermanyPosts: 828 |
@Bleep: Thank you very much! I happened to have the 320x340 version on the SD card and it worked straight away. My options are: Many thanks also to Geoff and Peter! Without them this great device would not have been possible! Frank |
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| lizby Guru Joined: 17/05/2016 Location: United StatesPosts: 3150 |
Frank--can you post the result of ?mm.hres,mm.vres Can you provide a link to where this particular ILI9488 is sold? PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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stanleyella Guru Joined: 25/06/2022 Location: United KingdomPosts: 2127 |
https://www.ebay.co.uk/itm/126156639999? is typical now with inflation |
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| lizby Guru Joined: 17/05/2016 Location: United StatesPosts: 3150 |
480x320, not, as per the other thread, "a USB Picomite with a 320x240 ILI9488 display." The options say ILI9488. I would have guessed this was actually 480x320, but if not, I wondered where it was available. Maybe this is not the same LCD. PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2135 |
320x240 was probably a typo. In the photos the text font and size look like 320x480, like all other ILI9488s. |
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| stanleyella Guru Joined: 25/06/2022 Location: United KingdomPosts: 2127 |
480x320 stupid size, 320x240 is lcd and vga. doesn't make graphics adaptable. |
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| phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2135 |
Code can be made to work with all screen sizes by scaling everything with MM.HRES and MM.VRES. |
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| lizby Guru Joined: 17/05/2016 Location: United StatesPosts: 3150 |
Try doing what Frank has done with half as many pixels. It can be done, but many of us would need our magnifying glasses. PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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| zeitfest Guru Joined: 31/07/2019 Location: AustraliaPosts: 482 |
Excellent !!  |
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| Frank N. Furter Guru Joined: 28/05/2012 Location: GermanyPosts: 828 |
 (This time with an illuminated heartbeat LED )Unfortunately not! I bought the displays via EBAY. It was a private individual who only had two left... But they are available on EBAY if you search for ILI9488. Frank |
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| lizby Guru Joined: 17/05/2016 Location: United StatesPosts: 3150 |
Thanks, Frank. 480x320. I have several ILI9488s with that resolution--bought on Aliexpress. I was wondering because the other thread had started off with mention of an "320x240 ILI9488". I thought that was probably a mistake--thanks for the confirmation. Great project--especially the nice enclosure and the wifi keyboard. It might make me go look for a wifi keyboard with more normal-sized keys. But there are many other projects on the go. PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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