mega2560 pro + 4pin OLED #22
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I have already started to port Martin's code to my hardware, so Martins code will be supported in the future. I have also moved the code to VSCode and platformio so it should be easier to get it compiled in the future. I will get you posted once I have a release that's worth publishing. |
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Hi Dirk. That's excellent, I rather have you experienced people do the final programming, though I will tinker about as would like to learn as I've got some other ideas I've written down for years. These arduino based boards are interesting and possible ways I could evaluate/test my ideas. Looking forward to your next code. |
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I have moved on, the Mega ran out of memory and speed for what I was trying to add. I went to the little esp32 with the OLED attached. I have made a very nice little PCB and enclosure for it. I've redone most of the code and it has many more features now! It even has a nice little menu system. |
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I am also working on a version using the TTGO T-Display. It will be in full color. |
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You can't build my new one for $22, but I think it is much better. The PCB (printed circuit board) is much easier to build and very compact. It has the card reader, logic level translator, and rotary dial attached so the only wiring is the battery and the LEDs. |
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"> Hi, Martin. I'm new to to Github and didnt know another way to discuss or ask questions." |
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BTW, I posted the schematic on thingiverse so you can build one by hand wiring if you wish and don't want to spend very much. For me, my time is worth more than hours of soldering and fiddling! |
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I created a phone app to control the new esp32 version. The esp32 has bluetooth builtin so I thought it would be fun to use it for something. It works right now, but it isn't really feature complete enough to post. I'll do that when I think it is good enough. You can select the bmp file, set the repeats and the frame time, and start the display. It works on both iPhone and Android. Is it useful? Not sure, but it is kind of fun to play with. You can control it while somebody else is holding it or it is just sitting there. You could put it on something moving like a merry-go-round and then start it with the phone. |
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I should look at VSCode. I only used Visual Studio because I was already using it for other projects and for my business work. I'm now retired so the business part doesn't matter at all. |
Yes, indeed :-) The goal of my project really is to make this technology accessible to everyone, without needing special parts. That's why my parts cost 22 dollars from china and 50 from amazon (at least here in Germany) I do like some of your additions, but as I use my pixelstick very often, there is nothing that I really miss from my version. Personal preference, I guess and maybe I am emotionally attached to my cheap pixelstick :-) So I guess I will stay on the mega with it's limitations and will port back some of your code into lighty. An ESP32 Board which looks promising for a project of this kind is the M5Stack, as it has everything needed already on board (SD reader, full color graphical display, buttons, bluetooth, Wifi, etc. A rotary encoder can easily be added, I think they also sell a ready made modul for it. The newer version has also a touchscreen and 3 capacitive button. If you will have a look at it and and to port the code to it, we could make a collaboration and I would be willing to donate a M5Stack to you. Price is slightly higher, but no soldering is needed which is also a big plus for users that want to make a cheaper pixelstick. |
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I just noticed the M5Stack yesterday. It does look interesting. No need to donate one, I'm more short of time than money. I'll order a couple of them soon and experiment with them. I had already made a touchscreen version and to be honest I found the rotary button much easier to use in the field, it's hard to beat one-handed operation. As far as building, I also agree, the less soldering the better! I've done lots of soldering over the years and made many PCB's, but I don't like to do it much anymore, especially since my eyes are getting older. |
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M5Stack with color display. |
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Strangely all my LED Strips work with the M5Stack and also with several Wemos D1 Minis which is also 3.3V. But the sacrificial LED with a diode is indeed a very easy option that can be done in case it doesn't work as expected. IN addition, SK6812 LEDs can be used which should just work with 3.3V out of the box. |
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This one looks interesting: |
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The ttgo with color display: |
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Thanks Martin for the information, I watched your product videos, quite extensive with a feature rich system. Your second one has come out exceptionally well. From your career and experienced background, you have the knowledge for these projects. As I've got the parts and being my first one, I'll want to continue with what Dirk continues to tweak, plus budget constraints. That rotary button seems like a good addition, the control seems very fluid and intuitive. Plus the tactile feel of it, reminds of a high end amplifier volume knob. It's interesting where your taking your ideas, much further than pixel stick. Hopefully, I'll create another one, trying on of your "final" builds. I do like tinkering about, and am always sketching or inventing some ideas and these miniboards have inspired me to pursue some ideas, perhaps get to a point of commercial manufacture, if design is feasible. I would be interested to see how you created the mechanism, that allows another bar to be attached. |
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I'm also trying to quickly educate myself, to get an understanding of the technical speak you both are discussing around electronics. Martin, that TTGO T-Display ESP32 you linked, is that what you base your current design on? |
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The PCB for my design is about $10+shipping from China, PCBWAY.com. All the parts except the esp32 are installed by them. I’m switching to the TTGO ESP32 instead of the Heltec one, the TTGO is $8 from China. So the cost is pretty reasonable in my opinion at least, <$20 (plus some shipping of course). PCBWAY also sells the TTGO, so I have asked them if they could install it on the PCB. They haven’t responded yet, but if they do that, there will be minimal work to build my system. The TTGO has a color display, so it will be very cool. It has enough pixels to do a preview of the image also. 140 pixels, so I’ll have to chop a few off the top and bottom, probably not noticeable anyway. It is my intention to have way more features than the real PixelStick. 😊
I visited England a few times when I still lived in Denmark, it was pretty easy to get there. My favorite fish and chips was a dingy little place somewhere in Liverpool. I did find the “English” hard to understand in Liverpool though. I thought my command of English was excellent until I got there!
I understand about budgets, I grew up dirt poor, we didn’t have much. My dad was a wonderful gardener though and we lived from his garden for a good part of the year. We mostly had meat when somebody gave it to us, other than that we were largely vegetarians, of course of necessity more than philosophy. I was a news photographer (like my dad) before I studied engineering. I tried weddings for a while, good money but too stressful for me. News photography was easier, if you messed up, 24 hours later nobody cared.
Where are you in England?
Sent from Mail for Windows 10
From: DaveStu
Sent: Thursday, December 3, 2020 10:46 AM
To: MartinNohr/LightWand
Cc: MartinNohr; Comment
Subject: Re: [MartinNohr/LightWand] mega2560 pro + 4pin OLED (#22)
Thanks Martin for the information, I watched your product videos, quite extensive with a feature rich system. Your second one has come out exceptionally well. From your career and experienced background, you have the knowledge for these projects.
I knew I should of done software develepment, alas I went into product design and engineering, though over time much of the engineering design&engineering has been sold out of the UK. We're extensively a services country. In recent times, I've been pursuing wedding photography and 2020 was suppose to be my year, but for some reason my plans got changed ha.
As I've got the parts and being my first one, I'll want to continue with what Dirk continues to tweak, plus budget constraints.
Life of an artist is somewhat frugal ha. I do however like some of the sample patterns you've added in, and the idea of using the wand as a static light bar is fantastic. I've done some studio work and that would work well, akin to using gels. I've seen some of the photography segment coloured led light bars, and they're super pricey.
That rotary button seems like a good addition, the control seems very fluid and intuitive. Plus the tactile feel of it, reminds of a high end amplifier volume knob. It's interesting where your taking your ideas, much further than pixel stick. Hopefully, I'll create another one, trying on of your "final" builds. I do like tinkering about, and am always sketching or inventing some ideas and these miniboards have inspired me to pursue some ideas, perhaps get to a point of commercial manufacture, if design is feasible.
I would be interested to see how you created the mechanism, that allows another bar to be attached.
My own goal is to stay with the 144 strip, split in half, then be able to snap together when needed. This will aid in transport/portability. I was thinking of pogo pins, to allow the electrical connection or something similar.
I'm waiting on some aluminium led profile, plus my LED strip, from spain.
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A custom PCB for $10+shipping, thats very reasonable and that's a single units? I assume that includes the rotary dial too. All parts except the TTGO board? If so, I maybe interested earleir than expected ha. IF I were to, I'd solder the TTGO myself, I like soldering. A colour display, thats spoling us now. I don't mind the more features philosophy, I've already hinted the knight rider car light sequence 😁 I'm most likely to have other ideas too. Oh so you had visited ye olde England and partook in fish & chips, I liverpool of all places. The Football team which I wholeheartedly support, small world. Yes, english in Liverpool is a complex drive, even a seasoned pro like me, can easily lose my bearings ha. There are plenty of more towns and cities where the experience is the same or more mind boggling. Yes weddings can be very stressful, but rewarding too. I like engaing with people in such an art, to be part of their day/journey and try to capture something for them to remember forever. I've never truly thought about press photography, I think nowadays though, like so many markets, its saturated. |
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When I worked for the paper, I also ran the darkroom. You had to know a lot of arcane stuff to get good photos. The cameras are a lot smarter now, anybody can get the technical aspects right. You still need a good eye for engaging photos though. Cameras are really just a tool for the artist. |
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Amazing progress here :-) Martin, I think the TTGO is the way to go, it's an amazing little device. I guess if we settle on the hardware and can all have the same base, we can build something great which is still accessible to many people for a reasonable price. Do you mind sharing a BOM list and also vendors so we can all have the same hardware for testing? I would then also create a 3d printable snapfit case for all the components. |
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How about this idea? I have done some testing using 4 AA NiMH batteries and it seems to work fine. That gives a nice option instead of the USB pack, which might not be available in the future anyway, at least the model I designed the case around. We can use a standard case or design one for 3d printing. I have noticed that the LED strips tend to go pink in color when the voltage drops below about 4.5, but the 4AA NiMH stay above for that for long time. We can't use regular AA because the voltage will be too high. We could add an LDO regulator, but that is one more part to add, and it will have to be sized for 3A to be safe. I prefer rechargeable batteries anyway, less garbage. I'll work on a new schematic in the next couple of days. We should probably create a new GitHub entry for this project. Do you have a good name for it? GoWand, GoLight, Golem(haha, probably not),, LEDGo, GoCheap PixaGoGo... :-) |
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BTW, I have already designed a 3D handle that has a mount for the rotary dial. It attaches to the aluminum extrusion for the LED strip. It is posted on Thingiverse. https://www.thingiverse.com/thing:4613446 |
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After using my wand last night I noticed that I sometimes bumped the dial and selected the next/previous bmp file and then when I pressed the button the wrong image was displayed. It was cold and my fingers were shaking! So I added a setting to control the dial sensitivity. You can now set it so more than one click is required to actually change the selection. I also made the timing between clicks adjustable so you can tune it to work the way you want. Problem solved! |
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Your ideas are just brilliant, as there are so many options once this finished. I drive a KIA, so I will skip the Cadillac Version and go for the standard components. I also want to make the case as small as possible by stacking the boards on top of each other. I use a special Powerbank for my pixelstick which works fine and also balances my stick, as the powerbank sits at the bottom and the controller is on the top. This way there is no chance in accidently bump into the dial. I have two handles, one in the middle and one on top. They use GoPro connectors, so they are easily adjustable. My complete stick weighs about 250 grams, weight is an issue for me as I carry the pixelstick around in the German Alps. I have just ordered the TTGO, a rotary encoder, an sd reader and a 1m LED Strip. I am really looking forward to this. How about lightyGO as for the name? I still have a Darkroom in my basement, a pretty small one. At https://www.youtube.com/watch?v=2C-RCoH6YP0 you can have a look :-) |
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@MartinNohr If I can get the PCB as single unit, then it seems reasonable and get the rest parts elsewhere, but am thinking of putting a handle design in the centre of the light wand. I find that theoretically more ergonomical and maneuverable in use, plus I'm still thinking of how to split the 144, with some sort of hingle locking mechanism within a aluminium profile. @dirkessl My led strip has arrived today from spain, from the link you gave. I'm confused somwhat as to the connections. |
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Power the LED strip directly from the USB connector, or at least the shortest wires, they use a lot of power! I posted a picture of the wiring harness that I made on the thingiverse entry. I ran power to the JST connection if I remember right. The ESP32 doesn't use very much power. |
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Dirkess: I had another idea for keeping the cost even lower. The TTGO has two buttons on the top. Put some tabs on the case to push those buttons. Then we have up and down and click both for select. Hold down both and we have the long press! Now we can skip the rotary button for the absolute cheapest and easiest. We can also skip the SD reader. The TTGO has BLE and Wifi. We can write some code to send the files to the TTGO. I'll have to check the memory usage, but there should be enough room for a couple of images on the board. We could jpeg the bmp's to make them smaller, but then we have to put in more code to expand the jpeg so that might not save us anything. We could strip the header from the bmp when we store it, since we don't really need it anymore, that would save a little space. If we want to be really clever we could at RLE the data, there is often lots of redundancy so they might shrink. I've already written a phone app that can read the files and control the system. It would be a simple matter to send a file to the TTGO. |
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@MartinNohr amazing idea. I really think we should go the modular way, it will make managing the code easier, having only one repository. With variables on the top everyone can compile the code for their specific hardware something like this: #define SDREADER //skips SD init and saves files on onboard storage If using VScode with platformio people also dont need to manually install libraries, as we can supply a platformio.ini with references to the libraries and they get downloaded on demand. For instance: lib_deps = I have just received my TTGO and it is truly a nice device. The buttons are a bit fiddly to press and from my experience, pressing two buttons at the same time is not reliable enough. I have the same problem on my M5Stack and will remove the two button functions in the future. Adding a third button would be a cheap option, but the rotary encoder I bought was EURO 1.5, so this will not break the bank and they are available on amazon as well. Inbuilt storage is also very nice idea. I guess easiest would be a small webserver where you can upload and delete images. No App needed. 4MB is not a lot, but better than nothing. My current SD card has 81 images with 14MB in totaI. I have created a first version of the web application to convert image files for a 144 LED pixelstick at https://www.essl.de/static/lighty/ it scales images down and rotates them. I will add an option to configure the LED strip length. I can add it to the repo once you have set up a new one if you want. |
I've got a little code cleanup to do before I start moving it to the TTGO. I used SD because at the time I couldn't make SDFat work on the ESP32. I've learned how to do that now, SDFat is much better, I used it on my older Arduino projects and found it to be much faster. I'll put SDFat back in the code. I think I'll also move the rotary dial handling into a class. I wrote my own because I couldn't find a library one that worked the way I thought it should. Maybe mine should be published as a library. Thinking about the BLE interface, that should be #defined out as well. It uses an enormous amount of space that might be better utilized for BMP storage. I'm not sure the phone app is all that useful. It was one of those "I wrote it because I could" projects. It'll be a couple of days before I can get a lot done on this. I have some other duties that are swallowing my time. Rental property, taking care of grandson, and garden cleanup. I'm excited about the project though, and I really appreciate your input and assistance. We will have the absolutely best device! |
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@dirkessl Thats nice and compact. Are you still using an external USB power supply? My LED profile arrived today. Was thinking of how to design and attach to it. Then I had a crazy eureka moment. In theory, I can get a small lenght of pipe with a spigot, insert into that adapter and use as a handle, and attach the electronics and power suppler. These adapters can use be angled, which I what I wanted so this has really been a lucky idea and it holds on tight. It also spins, but that will only work if the electronics are on the strip side. |
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Yes, I will keep using my powerbank, it’s basically part of my USB charging kit that I use when I am on the road. It’s so simple and convenient, I explain it from minute 9:20 in this video https://youtu.be/y_f5ck0Whnc On your flash holder, please make sure to replace the screw which holds the aluminum extrusion with something that can add a bit more torque, as there will be a lot of force one you start swinging it around and I have lost 2 flashes already with that holder. I think I need to make trip to the hardware store, these extrusions look very slim and adding a diffuser is something I miss on my current build |
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Oh Ok, I was just curious. I'm still using the power bank too, as you said, it has many purposes. I have a few to use, one even a car jump starter one with lots of juice and one that uses single 18500 batteries. Thanks for that tip, you're right. I will definately look for a better screw, only problem is, the threads are plastic. I will see If I could add metal screw mounts. I also want something that has a better grip to use with gloves. These are the dimestions of my extrusion. Very slim, but fairly strong as the the walls are thick |
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I now have some aluminium extrusions with diffusers on order and will try to build a connector that doesn't leave a gap between the two 144 LED strips. @MartinNohr is the number of LEDs configurable in the menu? I tried to port your code to the TTGO-display, but without too much luck, yet. But as we will have a hard lockdown in Germany from Wednesday on and I am off work, I will have a bit more time to look into it. |
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Thats cool. Your wand will be quite high! Should produce some fantastic large images, I was thinking of doing that too, but perhaps later. I've been looking at how to connect two strips together without a gap. I'm sure Martins handle design solves that, I'll keep tinkering with the design, as I'll need to wait for the coding. Btw Dirk, If you're on windows, what driver you using so I can test the board. When I plug in, blue LED pulses fast, screen flashes through colours then stays on yellow. Is that how yours was? |
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@dirkessl I figured out the ttgo driver and arduino control. digregard previous part of message. |
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Sorry guys, I had a really busy week last week and didn't get any time to work on this project. This week is looking better. I see lots of things happened while I was away. Among other things my LAN mysteriously stopped working and I spent hours tracking down a bad switch and some wiring. :-( Oh well, all is working again. |
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Regarding the gap between the two strips, I haven't really solved that one, so I hope you can up with something. I removed the wires and then soldered new ones on that went sideways so I did minimize the gap, but it can be seen in some images. If you look in thingiverse.com for the new version you can see how I soldered the wires. Note that there is always a slight gap in the middle of the 144 led strips because they are actually two 72 led strips soldered together. I have looked at strips from several different companies and they are all made that way. I can see a small black line in the images where that join is. Have any of you seen any strips without the solder joint at 72? |
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@MartinNohr I have desoldered and soldered my strip back together tightly to get rid of the gap, as it was really annoying and showing in all the images. As those strips are not really meant to show pictures, companies might just not care about the tiny gap. |
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I had a quick go for the connector, no idea if it will work out. the goal would be to bring the wiring down into the printed plastic connector to allow a gapless connection. The wiring itself is not shown in the CAD drawing.
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That certainly looks interesting. Remember that the LED's only feed input data from one side so this won't work with feeding both LED's in the middle like I did. I only did that to avoid running a wire down the length of the strip. I had to play a bunch of tricks in the software to do that since one of the strips is effectively "upside down". I like your idea though and it would be easy enough to change the software back to just treat the strip as a length of N leds. In fact, it would probably execute the code faster! The only drawback is three wires down to the bottom of the strip. The good news is that we could easily support as many or as few strips as you want. I love the idea of a foldable one, but even a pluggable one would be great. That black line can be annoying! We will soon have the absolute best "pixelstick" around. |
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I wonder if we can bend that join at 72 pixels to mash them a little bit closer? I'll have a look at that later today. |
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lightyGO would be ok as the name, but it doesn't really give a hint as to what it does. If we can't come up with anything better we could certainly use it, but lets think about it a bit more. That's why I haven't create a new repo yet. I want a great name! |
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there could as well be a connector on the back which joins the 2 two strips from the middle, so no additional cable would be needed. In theory the PWM cable should be enough, as it doesnt matter if power comes from either side, or am I wrong? could the aluminium extrusion itself be the pwm signal 'cable', or will it imply too much noise? |
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Have you seen this one? |
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Yes, the power can come from either side. It isn't a PWM signal (it is an interesting way to send binary data), but it only requires the data and ground connections. |
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The way it works is that it sends 24bits of data. Each 24bits is sent on to the next chip. This color data is latched in each chip. When the data line stays low for (if I remember right) > 50uS the data is transferred to the leds. What this means is that the data has to come from one end as a stream of data, the first 24bits end up at the end of the strip. So, I guess we could still feed the data to two strips from the middle, but it does make it more complicated if we wanted to support other sizes like 3 strips or 72 leds etc. If you always feed from one end then you can just add as many leds as you want, you just chain them together. |
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more... the data line gets 24bits for each led, so if you had 144, then 14424 bits is sent. Or you could also say 1443 bytes. If you only send 6 bytes then only the first two leds will change color. The timing is how 0 and 1 are determined, the stream is terminated by sending digital 0 for a long time. |
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Hey, it changed my text... 144 x 24 and 133 x 3. |
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144 x 3... |
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What about PixelWand, as this thing is magic and sends pixels. It's amazing how much light painting stuff you can buy for way too much money. Have a look at https://github.com/Aircoookie/WLED . I have already build some stuff based on this firmware and it has really everything you need, but no local display, so it relies completely on a phone app or other network methods. If WLED gets a local display and some input buttons, it is very easy to make great light painting equipment for small money. As said, I myself prefer using the stick without an app, because it is just easier in my opinion and I dont want to rely on another piece of hardware if I am out shooting. Your explanation totally makes sense, thank you very much! I guess this is a minor thing how more strips can be chained together. Whatever works is fine. ;-) |
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And also your menu system is one of the best (if not the best) that I have seen. |
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Appreciate that! I like my menu system too. |
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MartinsMagicPixelWand? |
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MNPixelWand, MagicPixelWand, LightPixelWand, MagicLightWand, MNMagicPixel |
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We don't need my name in there, I'm not the only guy working on this design now, and I'm not that egotistical! |
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MagicImageWand sounds absolutely spot on. also .miw files are not taken by anything. I think you can be egotistical, as you do all the coding work. I need to get some sleep now and dream about this gapless connector |
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regarding the WLED comments. I like the standalone operation especially for photography. I don't want to have to grab my phone or a computer to control the thing. The only app use I could see was to have an assistant start the camera and light from somewhere else. I solve that problem by having a radio control on my camera. Then I open the shutter and start walking. Works fine. |
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I'll go ahead and create MagicImageWand repo, I'll send you a link later, I have to go to the shop to do a little woodwork to fix my neighbors table, then I'll get back to this. Goodnight. |
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Let's continue our discussions on the new repo. |
Hi, Martin. I'm new to to Github and didnt know another way to discuss or ask questions.
During this covid lockdown madness decided to build a similar lightwand, after finding a post on a photography website for a
cheap build. I followed this guide:
https://www.essl.de/2020/03/14/lighty-a-pixelstick-on-the-cheap/.
Incidentally, he also found inspiration from Michael Ross's original design, albeit Dirk swapped out some parts.
My question is, with your added/tweaked features could I transition you code to my hardware.
Please keep in mind, I have no clue in programming, though I have been trying to understand it with Arduino.
Thank you
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