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Forum Index : Microcontroller and PC projects : Considerations for a potential "EduMite"
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Nimue Guru  Joined: 06/08/2020 Location: United KingdomPosts: 367 |
Further to discussion on another thread - here Attached is a preliminary justification and outline spec of an "EduMite". I am in no way precious about what I've written and the "spec" is more like a wish list, so I appreciate that it might be totally unreasonable. TL;DR: Imagining something like a CMM2 form factor with a few integrated sensors (LDR/DHT22), LEDs and connectors - that can be programmed via terminal over Bluetooth. I wonder if such a thing could be assembled to a price point -- say sub £50/$65 Here's my ramblings: EduMite.pdf Any and all comments welcome. N Entropy is not what it used to be |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 3649 |
Very interesting. The small PCBs look doable, perhaps each a different size/shape, silkscreen can say what each is, connectors - I'd overlooked banana plugs when I mentioned croc clips. Maybe the edge connector for a croc clip is cheaper? Probably each has to be electronically robust (easy for many of them). I suppose if the very young are to use things we need to consider choking hazards. In case WiFi / SSID/pwd are used maybe make a standard "router" (access point) with standard SSID&pwd so all the Picomites are pre-programmed with the SSID & pwd without any teacher having to do it. John Edited 2023-03-20 07:19 by JohnS |
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| Nimue Guru Joined: 06/08/2020 Location: United KingdomPosts: 367 |
100% -- 10kΩ, diode / LED symbol etc in the silkscreen Banana plug sockets on the box - cables with banana plugs on one end, croc clips on the other fixed with the screw on the croc clip. Or banana to banana - and let the kiddos add the croc clips. Yes, but by year 4/5/6 - ages 8/9/10 the likely target audience - not normally an issue. The number of times I've broken out of school networks with the access point I carry round - and suddenly I have a "jail broken" network -- used to do that back in my own class back in the day. The more "IT" lock things down, the more we all want to rebel. N Edited 2023-03-20 08:29 by Nimue Entropy is not what it used to be |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 8565 |
What are the students using as a host? I don't understand how bluetooth would work in a classroom. Wouldn't the kids all end up connected to each others modules? Can you even use that many bluetooth devices in a small space? |
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| Nimue Guru Joined: 06/08/2020 Location: United KingdomPosts: 367 |
Each student will have a host PC (mostly a Windows based laptop) with either Bluetooth on board, or Bluetooth dongle. BUT -- you are absolutely correct re the number in close proximity -- DOH!! Whilst i imagine Bluetooth itself could cope with so many in proximity -- how would they know which to 'EduMite to pair with their PC itself. I can see total confusion here -- exactly what I was looking to stop. Scrap the Bluetooth -- USB it is. ;-) [For what it's worth, I was also trying to sneak in remote access -- so an 'EduMite could be used to monitor something and the output displayed on a teachers PC without physical connection. I guess this could still be built in if a Bluetooth module was added after] Good feedback. N Entropy is not what it used to be |
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| robert.rozee Guru Joined: 31/12/2012 Location: New ZealandPosts: 2285 |
ADDENDUM: OOPS... i walked away while writing the below, and so posted an hour after Nimue had answered  will leave what i wrote, as there may still be some useful pointers.think of an open-plan office full of bluetooth mice - so there should be no problem on that front in a classroom. however, i've played with an HC-06 bluetooth module and can see some complications in a classroom situation. the module was hooked up to a USB to serial bridge attached to a netbook. the netbook was then connecting to the module via bluetooth. once set up this gave me two serial ports which i could talk back and forth between using two terminal emulators. so no micromites involved, just simple comms. once (finally) running, everything worked quite well. but getting it running required a bit of fiddling with a randomly generated 6-digit pin number required for the module to connect. multiplying this sort of issue by 20 students trying to configure 20 bluetooth modules all at once, and each asking for a different PIN to allow connection, and you can see headaches. not to mention the fact that in a classroom of 20, every student would have TWENTY different modules appearing on their computers to choose between! ideally, the (HC-06) modules would at the least need custom firmware, if not an attached small LCD and perhaps a custom bluetooth driver or 'helper' for the student computers. cheers, rob :-) Edited 2023-03-20 22:36 by robert.rozee |
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atmega8 Guru Joined: 19/11/2013 Location: GermanyPosts: 711 |
Consider a Linux server as "HUB" with Ser2net on one litte LINUX (Raspi) with cheap usb rs232 converters. Or: Why not just use the new PICO w with Telnet and WLAN? |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 3649 |
If it's suitable, yes. And as I suggested, pre-programming SSID&pwd into them. (And to do that there probably has to be SSID&pwd which are known in advance and not input by teacher let alone kids.) However it's all done, has to be up & working almost immediately and without any fussing over PINs or SSID/pwd etc. Can't waste time or get into knots in a lesson. John |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 5699 |
A) They are using (and need) separate PCs so a server doesn't *have* to be used. It's probably a "nice to have". A USB "tether" isn't a bad idea either (even better if it's terminated inside the case). Such things give the impression that the box is part of the PC and can't be slipped into a pocket and taken away... B) Why complicate things with Telnet and WLAN? This has to be maintainable by overworked and underpaid staff who have no interest in doing the job because it eats into their teaching time. Some of them think a router is a motorised thingy that sprays bits of wood everywhere. The less complication the better. I used to design boilerhouse control panels (among other things). Council policy changed and there were, relatively suddenly, no people around that knew how the school heating systems worked. It's a job that fell on the head teachers. Now, these are definitely not stupid people, but they are not heating or control panel engineers. Some got the hang of setting things pretty quickly, others were not too great at it and needed an appreciable amount of hand holding if the system had an optimiser, compensator and two or three sets of pumps. If I, personally, wanted to network a load of PicoMites I'd probably use multi-drop RS-232 because it's so easy to implement. Now we have MATH(CRCn) it's even better and should be pretty bomb-proof in a classroom. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Nimue Guru Joined: 06/08/2020 Location: United KingdomPosts: 367 |
For use in schools, especially primary -- it needs to be "plug in and use". The following would work: (1) Plug device into USB (PC - probably Windows based) (2) Fire up terminal software of some sort (3) Connect to EduMite (4) Code All my comments related to "wireless" were aimed at two things: (1) Emphasizing that the EduMite is not "controlled" by the PC (2) To allow "wireless" data acuqusition Happy to drop (1) for sake of simplicity and (2) can be achieved if wanted after the event with a bluetooth module. For this to work -- it has to be as "plug in and code" -able as possible. N Entropy is not what it used to be |
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| atmega8 Guru Joined: 19/11/2013 Location: GermanyPosts: 711 |
So stay with PC and USB Cable. |
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| lizby Guru Joined: 17/05/2016 Location: United StatesPosts: 3008 |
Why wouldn't something like the GL.iNet MT300N running openWrt (pre-installed) with an AP name of something like "PicoMiteWeb_Hub" and whatever as password work with the Pico W with the PicoMiteWeb firmware? The MT300N wouldn't need any internet connection--it would just serve to provide a local network to the PicoMiteWeb devices. However, the Pico_Ws would cost about 3 times as as an original Pico with wired USB connection. PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 8565 |
The big question for me on this project is "Box, or no box?" Creating a box large enough for what is wanted with multiple cut-outs is likely to cost as much as the rest of the project put together. Can you manage with a PCB only (on stand-offs). If necessary we could get it made from 2mm stock which would be completely rigid. Then it would be easy to plug and unplug etc. |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 5699 |
Can someone non-technical maintain the system? Someone who doesn't know what a command line is and has to have the concept of "IP address" explained to them? Not all schools have these people. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 5699 |
I think, if there's a LCD display, there has to be a box. If it's just a device hanging from a USB lead then it may not need a box as such, but it does need protection (e.g. plastic sheet above & below the PCB) against things dropped on it and it being knocked off onto the floor. And chewing gum. Edited 2023-03-22 03:06 by Mixtel90 Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Volhout Guru Joined: 05/03/2018 Location: NetherlandsPosts: 3483 |
You could surface mount the mite at the bottom of a pcb and only have robust io pins through hole at the top. This way you can use the pcb as a lid on a plastic box. Something like a cheap lunch box. So only switches,sensors,led and lcd display can be touched. Power through usb from the smd pads under the pico using a robust USB B connector. Real old school, but robust Volhout Edited 2023-03-22 03:40 by Volhout PicomiteVGA PETSCII ROBOTS |
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| Nimue Guru Joined: 06/08/2020 Location: United KingdomPosts: 367 |
Realistically a box is required -- oddly, not so much from the perspective of protecting the components, but rather more of mounting the LCD / buttons and plugs. Childrens fine motor control can be awful -- plugging things in always gets lateral forces -- so a box is needed to help with the structure. Yea - Will have to add the cost in. Maintenance wise, plug / play is the name of the game. For example, whilst a wireless access point is a great idea -- actually configuring the access point itself to navigate the schools network (often things like DHCP are disabled - static IPs are the name of the game) - can be next to impossible. I work for the local authorities and even I need to promise the next seven generations of male children before I can get access. So I think USB cable / tether is the most realistic. N Entropy is not what it used to be |
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| JohnS Guru Joined: 18/11/2011 Location: United KingdomPosts: 3649 |
One of the reasons I mention pre-programming was so that no such person would be needed nor anyone grasping the concepts. But the cost may rule it out. I'd read that plugging in via USB was not wanted but that's been relaxed. Good - USB is cheaper. John |
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| lizby Guru Joined: 17/05/2016 Location: United StatesPosts: 3008 |
The point of the MT300N or similar access point is that it could be entirely local--no need to connect to the school network. And with each PicoMiteWeb device displaying its IP number, a PC would connect to the PicoMiteWebHub access point, and then with TeraTerm, connect to the Picomiteweb's given IP address. PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 8565 |
These could all be done permanent mounted to the PCB I genuinely believe we are talking about the difference between feasible and not-feasible. I assume this would be of a scale where 3D print etc is out of the question so we are talking about a custom enclosure and if things like sockets are mounted to the enclosure rather than the PCB then build costs will immediately jump massively |
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