Project Patchouli: Open-source electromagnetic drawing tablet hardware(patchouli.readthedocs.io) |
Project Patchouli: Open-source electromagnetic drawing tablet hardware(patchouli.readthedocs.io) |
I've played with simple electronics on the arduino and raspberry pi platforms but this is a whole new level. Anyone gone down this path? Something you would recommend?
Making a working circuit is honestly very easy once you know the basics. Look inside a Made in China knockoff appliance, and you'll see that most things can be made from a couple of conponents and a microcontroller. Pull apart an old TV remote or bluetooth device, and look up the part numbers and what they do. There's not much to it. You have to remember that most of the stuff getting designed and built in South East Asia is done by people with zero qualifications. Electronics being "the thing that smart university people do" in the West is mostly a mental block, culturally constructed because people don't want their kids getting electrocuted so bombard them with constant threat of death if playing with electricity (which mostly isn't a worry anymore unless you're working with mains power).
The true discipline of Electronic Engineering is designing something that works for every eventuality and environment, with close to 100% reliability, at the very cutting edge of what is possible with the components we can afford while balancing physical and financial constraints. That's something which takes years of both academic study and industrial experience.
very good recommendation, that book help me turn my studies in to reality
electronic circuit emulators will help with the basics as well (eg https://www.falstad.com/circuit/)
I'd recommend also to play with https://www.falstad.com/circuit/circuitjs.html
I got this advice in 1998. I have the book. I found it useful for the "art" part. It got me through the projects that I was working on at the time, but personally it didn't help me with the fundamentals. Paraphrasing what has been said on this site many times in the past: AoE is a great first book in practical electronics if you already have an undergraduate degree in physics. I showed my brother AoE when he was building guitar pedals and he couldn't make sense of it and said it was obviously assuming things that he didn't know (he had no high-school science background).
There are a lot of potential and/or assumed pre-requistites even for basic electronics: high school physics, first-year calculus, maybe a differential equations course, certainly familiarity with complex numbers. As I understand it EEs take vector calculus and classical electromagnetism, that's a long road for self-study. For that reason it's hard to give general advice about where to begin.
For someone starting out I think the first things to study are DC and then AC analysis of passive circuits (networks of resistors, capacitors, inductors), starting with networks of resistors. Ohms Law, what current and voltage actually mean, some basic introduction to the physics passive components. This is the basics, and I don't see AoE getting anyone over this hump. This could be learnt in many ways, electronics technicians and amateur radio people know this stuff -- there are no doubt courses outside university both on line and in person. If we're talking books, get a second hand copy of Grob's "Basic Electronics." Once that's covered you can move on to semiconductors. I can recommend Malvino's "Electronic Principles," but this book won't teach you about resistors, capacitors and inductors. After that I think the Art of Electronics would be approachable. And also more specialised topics like digital design or operational amplifier circuits.
A book that usually gets a mention is Paul Scherz "Practical Electronics for Inventors." I got that book later, I personally found it a bit overwhelming with the mixture of really basic practical stuff combined with more advanced circuit theory, but it's no doubt popular for a reason.
Another standard recommendation is to buy one ARRL Handbook from each decade (I have 1988), the older ones have less advanced (hence more accessible) material. But reading the "Electronics Fundamentals" chapter is no substitute for Grob and Malvino.
Bigclivedotcom (nice, basic fun) : https://www.youtube.com/@bigclivedotcom/videos
Mend it Mark (more advanced) :https://www.youtube.com/@MendItMark/videos
Boylestad was an excellent first look at electronics with S&S being great for going in-depth on some topics.
Pick up (broken) equipment and start disassembling it to figure out how they turn A into B [1]. Go down the rabbit hole of hunting down the service manual of the thing or one of its siblings. Look at how the pcbs follow the same pattern in competing design. Look at how all the yamaha, sony, medion, … amplifier/tuners are made in the same way and learn from it. Notice that one that is costlier and has those few quircks in its design. Notice how different variations of a theme achieve the same result, but died out because the tech doesn’t scale or simply proved to be suboptimal. Try to repair your broken equipment by understanding the path that the signals and power lines follow.
Rinse and repeat a few years and you’ll get a grasp on what the innards of an unknown electronic thing looks like without opening it. Then open it and be amazed that there was a different, cheaper, simpler way to turn A into B.
All along the way you’ll experience that most educational resources aren’t actually that good at explaining, or that they follow a different school of mathematical notation, or that they’re really good at explaining this detail but the rest is missing.
Design your own pcbs. Remember that - like software - hardware design is iterative. Remember that - unlike software - hardware iterations cost money.
Hope this helps.
[1] the ways to turn A into B are rather limited and it relies heavily on electromagnetism and conservation of energy.
You can build a micro-controller with a circuit that controls a stepper motor. Let the motor do something simple/fun. Connect the fun doohikie to give feedback to the microcontroller — e.g. using some kind of an encoder chip that converts motor's rotation amount to numbers that will tell the microcontroller how much to move, initialize the doohikie's start state.
But you can understand a lot more if you don't use the HBridge chip for the motor. Build the bridge circuit yourself. Build your own power supply for the microcontroller too(if you want to).
You can pick a path to go down on and focus on specific parts:
1. For the h bridge there is lots to learn. Designing the operational amp for D2A conversion as well as amplification/signal modeling — which you will need for the motor for current limiting in the h bridge per motor spec for the doohickie you want to power — That will teach you quite a bit about analog electronics and design. What kind of currents you need to protect and how e.g. using opto electronics. Limiting noise from power supply and parasitic noise so that your circuit does not misfire. You will likely need a set up of an oscilloscope, soldering irons and breadboards to prototype. Learn some basics from a book about design then go back to the circuit and build.
2. If you build your own PCB for this. It is a multi month project. You can learn a out CAD and chip layout. But I think you can do this in parts for example you can design the initial PCB only for the digital components and then connect it to a breadboard where you can prototype the H bridge you want.
3. If you choose to learn digital design and embedded system programming then maybe you can build the tougher analog parts for motor control using store-bought components and chips and focus mostly on the programming the microcontroller. That is a totally legitimate part too. You could use an old MCS-51 microcontroller and learn about data and program memory addressing and interrupt handling from scratch.
Controversial opinion but you do not need to learn electronics to have a good time. One can have plenty of fun simply writing software and plugging prebuilt modules together on a breadboard. Ohm and Maxwell need not apply.
And then yeah he's playing a Touhou rearrangement in the project intro video. "Original: ZUN".
I wholeheartedly support weebs who create useful open-source electronics and share them with the world.
Anyway I'd be interested in the implementation of a 3D mouse also.
I wonder why Apple still uses active pens on the iPad when passive EMR has become such a commodity. Maybe it's just rent-seeking, a passive pen would probably be much easier to clone without paying Apples MFi fees.
Anyone have any idea whether the touchpad part could be made open-source? Or even some closed sourced off-the-shelf solution that could be integrated with the above?
EDIT: There is a Canadian company that has recently released an open source trackpad called the Ploopy Trackpad [1].
[1] https://github.com/ploopyco/trackpad https://ploopy.co/trackpad/
The creator of it has showcased the prototype at an osu!* streamer's channel (since low-latency absolute positioning devices are highly desired for playing osu!): https://www.youtube.com/watch?v=v1afJ7OpacU
* that is osu! (sic) rhythm game, not to be confused with OSU universities
The showcase video didn't look very convincing and neither website nor the discord channel contained a lot more information. Although I didn't dig through discord history too carefully.
It's one thing to hook up 200 hall effect sensors to a MCU, and read few of them or send data over HID at 8000Hz. It's different thing to read all 200 at 8000Hz and figure out the position with reasonable resolution and accuracy.
Can it also detect the exact moment pen touches tablet or additional button clicks? Or does it require taping keyboard with other hand? Which is probably fine for OSU, but less so for drawing.
Basically:
- Pen click is useless for osu! or can just be digital, while artists would want analog pressure
- Buttons on a pen are actively detrimental for osu! but very useful for artists
- Smoothing on a tablet is more detrimental for osu! the more of it there is but absolutely necessary for artists
- High polling rate is useless for artists (they would have input delay due to the smoothing they need either way) but very useful for osu!
- Big tablets are useless for osu! players as they typically only use a 5-15cm area while they are very useful for artists
I think the entire point of something like pompyboard is to make a tablet just for osu!, which doesn’t exist right now. Meanwhile for artists there is already a whole industry of tablets available for them
If you meant for the comment to be read by the content poster, then something more meaningful than a single-word response would have been more appropriate.
These are the rules and practices which have kept HN lean and functional over nearly two decades.
I configure the tablets in the "Relative" mode, in which they behave exactly like a mouse, unlike in their default "Absolute" mode. I configure left click to be done by touching the tablet with the stylus and the 2 buttons that are on the stylus to generate right click and double left click.
The advantage over a mouse or trackball is the much more comfortable position of the hand and also the much higher speed and accuracy of positioning. Moving the pointer to any location on the screen is instantaneous and without any effort, due the lightness of the stylus and to the lack of contact with the tablet.
Because the stylus is extremely light, I can touch type on the keyboard while still keeping the stylus between my fingers. This allows faster transitions between keyboard and graphic pointer than with a standard mouse (because the time needed to grip the mouse is eliminated). Only when I type longer texts, I drop the stylus on the tablet.
The tablet is no bigger than a traditional mouse pad, so it does not need a bigger space on the desk.
After switching to use exclusively a graphic tablet, I would never want to use again a mouse, trackball, trackpoint or touchpad. I only regret that I have never thought earlier to try this.
Besides being a better mouse than a mouse, a tablet obviously allows to do things for which a mouse is inappropriate, e.g. drawing or handwriting (e.g. for signing a document).
I should mention that I have always used the Wacom tablets with Linux. I have never tried them on Windows, so I do not know if there they work as well.
MacOS is well-supported once the drivers are installed, though sometimes the driver doesn't seem to pick up tablet (either after the laptop or tablet goes to sleep). Restarting the driver fixes this, though this bug seems to have been fixed in the latest driver release. Linux works out of the box (at least on KDE/Arch), though sadly customization support on Wayland isn't quite there yet compared with what you could do on X11 (with the xsetwacom utility). For drawing support though it should work perfectly but as far as I know you can't the the button functionality, which is a bummer when using it as a pointing device.
The main benefit for me is that it feels much more ergonomic compared with a regular mouse or even a vertical mouse or trackball and I don't get anywhere near as much wrist or shoulder pain - especially in the cold temps in the middle of winter where I am. There is a bit of an adjustment period and I find for interacting with small UI elements such as buttons it can be a bit tricky, but for me the benefits outweigh the downsides. The only other downside I can think of is that when using the tablet over bluetooth (wired is also an option and tracks a little more smoothly) the battery only lasts 1½ days compared with the weeks/months a wireless mouse would go for.
Annoyances: games that require you to push the cursor against the edge of the screen to move the view, app/website developers who force tiny scrollbars that constantly hide themselves despite me setting the OS to never hide scrollbars, having to restart the tablet drivers most of the time when I move between having the laptop docked with the big screen and big tablet on the desk, and taking it out to a cafe or the park and using the smaller tablet that lives in my laptop bag.
I've dreamed of using a stylus and tablet since reading _The Mote in God's Eye_ when I was young, and have preferred to use them since using a "Koalapad" attached to a Commodore 64 in the school computer lab when I was young.
The NCR-3125 I had was donated to The Smithsonian by the guy I sold it to, along w/ a lot of other materials on pen computing --- PenPoint was my favourite OS alongside NeXTstep, and the high-watermark of my computing experience was using the NCR running PenPoint as a portable, then cabling it up to my NeXT Cube to transfer data --- had a Wacom ArtZ attached to the Cube, so still had a stylus, just it wasn't a screen.
Futurewave Smartsketch is still my favourite drawing program, and I was very glad that its drawing system made its way through Flash and into Freehand/MX (which I still use by preference and despair of replacing). If you have a graphics tablet, be sure to try out:
Hopefully the folks making Graphite will figure out that it's a core functionality for a drawing program to work w/ a graphics tablet --- haven't been able to do anything when I've tried.
I sketch (either on a Samsung Galaxy Note 10+ or Kindle Scribe or Wacom One or Samsung Galaxy Book 3 Pro 360), take notes (mostly on the Scribe), do block-programming (Wacom One or Book 3), or draw (on the Book 3).
When it doesn’t anymore I’ll need to get something else, probably an iPad so I can also use it as a 2nd screen.
Anyway there are plenty of things like https://wokwi.com and it's fun ... but it's NOT like the actual hardware. Most of those projects precisely make sense because of the tangible aspect, or because you support a "vision" (e.g. Precursor) and learn while tinkering with them.
So... no unfortunately sorry I don't have any recommendation for doing this virtually. Maybe it exists but I'd caution against thinking it's equivalent.
Text comments here are supposed to have more content. (And lamenting about downvotes has a high chance of getting more downvotes)