Badger 2040 – Fast updating RP2040 based e-Ink badge | Hacker News Reader

Badger 2040 – Fast updating RP2040 based e-Ink badge

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240 pointswhiskers62 comments

What does the idle power draw look like? I've always been super disappointed at the power draw of maker MCUs; just keeping the regulator on 24/7 depletes a moderately-sized battery in a matter of days.

It would be nice if they put something like a TPL5111 on board, which is an ultra low power device that can turn on at a set time interval, and then turn off on demand. So it will pull up the "enable" pin on your regulator, your microcontroller will boot, your program updates the display, and then you tell the TPL5111 to turn off, and you draw basically no power until the next refresh cycle. I actually use a RP2040 with one of these to drive an e-ink display that measures the humidity in my 3D printer filament dry box. It wakes up every couple hours to update the humidity (it doesn't change much), and I've been powering it from a 400mAh Lipo battery for several months that way. To me it was groundbreaking to bite the bullet and add another device to conserve power, the results are excellent. Would love to see a provision for one built into the next version. (And hey, dump a BME280 on there and I can replace my entire hacked-together device with one circuit board and a battery ;)

(Oh, and for people asking why I built my own humidity meter using complicated electronics and a computer program instead of a $2 jobbie powered from a coin cell that you can buy on Amazon, it's because I wanted to be pretty accurate with the measurements. 10% humidity is different than 9% humidity in this case. As for why an e-ink display instead of an ESP32 that writes the value to some database server and I get a text message when I need to recharge the dehumidifier... it's because I didn't feel like writing that particular computer program at the time. Wifi connection errors. Authentication tokens. I'll just look at the display when I walk past ;)

You can shut down power almost entirely with circuitry to trigger a wake from sleep when pressing a button. It's no RTC but a compromise we made to hit the price point and allow for a very long battery life!

OK, makes sense. I looked at the schematic and saw a lot tied to the regulator enable pin, and that compromise sounds great for the badge use case.

After a quick look at the schematic it appears the current in the off state is somewhere around 3uA.

Customized board ESP32 could have deep sleep mode with wifi, I couldn't see the reason of choosing rp2040 not ESP32. Prob just due to rp2040 is cooler than ESP32?>

Because it's designed by a Pi specialist retailer

> In honour of Raspberry Pi's 10th birthday

And possibly also because rp2040 is readily available these days. Are esp32 stocks - and therefore prices - currently in the same good shape (honest question)?

ESP32 has been pretty good whenever I have checked them. An right now 10k stock on Digikey for esp32-wrover, at standard prices, and manufacturer lead times still listed as 8 weeks.

These tiny eInk screens are fun and it is nice to see them pop up in more places. They are a bit of a pain to work with if you want anything more than just "black and white, full flashing refresh" but with effort you can coax greyscale and partial updates out of them, despite them not officially supporting such features. I published some info here: http://dmitry.gr/?r=05.Projects&proj=29.%20eInk%20Price%20Ta...

I haven't tried them, but I have seen 3-color e-ink in about the same size as the Badger, like this one[1].

1: https://www.adafruit.com/product/3933

3 color ones are much harder to get clean greyscale out of. but yellowscale and brownscale is easy :D

What an amazing write up. You are incredibly talented and you didn’t have to go the extra step to blog your findings, but you did.

Thank you for sharing your work with the World Wide Web.

Where/how do you actually buy these Chroma displays?

eBay. They appear sometimes. Eg: https://www.ebay.com/itm/283340935671

Thanks; it's been so long since I used eBay I completely forgot to check it!

To save someone else the trouble of checking; to ship to the USA:

- Badger 2040 Only: GBP £16.00 ($21.46)

- Gadget 2040 + Accessory Kit: GBP £24.25 ($32.53)

Maybe a couple of bucks more if you want the tracked international postage instead of the (cheapest) untracked.

Video about it:

https://www.youtube.com/watch?v=RDhw3BlBtig

So if you use this as a name-badge with no batteries, the buttons and ports on the rear are very exposed; I wonder if there would be long term consequences of that? Might need to use e.g. glue-gun glue to protect them.

Also, the branding is a lot. If it is a toy then it isn't important, if you were serious about a name badge a little bit unprofessional looking. Particularly the bomb/weapon on the rear with a bunch of exposed circuit board, I'm sure going through TSA with this will be a hoot.

Just comes back to: Is this actually meant to be used as a name badge? Fun rainy afternoon toy though.

I mean it's aimed at makers, so it's expected that you'll use it for some sort of "interesting project" rather than take it out of your bag, program it to display your name, and use it instead of a sticker.

I've traveled with a lot of ham radio gear over the years, and sometimes the TSA wants to take a look. The worst case is that they swab it for explosive residue. Adds a minute to the transit time through the checkpoint, worst case.

> The worst case is that they swab it for explosive residue

The worst is that you'll have guns pointed at you and get arrested:

https://www.theregister.com/2007/09/21/mit_student_arrested_...

> wore a circuit board with nine lights over a hoodie and was inexplicably grasping a hand full of Play-Doh

Not quite the same thing as ham equipment in a suitcase.

>Simpson, who is a sophomore in electrical engineering at MIT, wore a circuit board with nine lights over a hoodie and was inexplicably grasping a hand full of Play-Doh.

Lucky she wasn't shot.

This is like the pwnagotchi I've always wanted. I hope the project supports it.

The RP2040 has no wifi radio or network support unless you add them, so you may be out of luck here.

This would be cool to make this into an airgapped TOTP device if an RTC is added

Great idea. Could be still cheaper than most TOTP devices.

That's really cool!

It would be interesting to see it be more commercially-viable. It probably wouldn't really work with NFC (but I'd love to be wrong).

It would also be great for spy movies.

With the STEMMA QT port you can attach something like this $4 RFID breakout[1] and have a badge that people can scan at a conference to get your details. No soldering needed, you can connect it directly to the board with a $1 cable and it's probably easy to program with MicroPython, although I'm not sure how extensible their "Badge OS" is.

edit: there's no MicroPython library for it apparently, but the datasheet[2] is pretty detailed. I've written Python libraries from such protocol definitions before, it's not too difficult.

[1] https://www.adafruit.com/product/4701

[2] https://www.st.com/resource/en/datasheet/st25dv04k.pdf

Why wouldn't it work with NFC? NFC doesn't require onboard power, the reader powers it.

I think that they don't have it set up for NFC.

If they did, the chip could be programmed, along with the badge face.

Got one for me and two for the kids, I think they'll love it. The battery situation is slightly annoying but I guess I'll make do.

I have a few things laying around that could benefit from screens, but didn't justify $40+ screens. This is fantastic and cheap. Instant purchase.

> Never set your password as "mushroom". It is not stroganoff.

Niche British internet humour there.

It is a snakerboard

Cute I guess, though no idea why I'd want an e-ink name badge. I wish there were more affordable large e-ink screens. These tiny ones don't do much for me.

It does seem to me that the rpi pico is maybe the goto cheap MCU board these days. Not much reason to use a blue pill or arduino clone any more, unless I've missed something.

Check out Inkplate for larger, affordable, ready-to-program, e-ink screens - they have both 6" and 10", and even color!

https://www.crowdsupply.com/soldered/inkplate-6

https://www.crowdsupply.com/soldered/inkplate-10

https://www.crowdsupply.com/soldered/inkplate-6color

Yeah I know about the inkplate, I might get the 10", or maybe they will do a 10+ analogously to the 6+, but I'd like an even bigger one. The ipad pro that everyone wants is 12.9" and a letter sized sheet of paper is 14" so I'd want to start up in that range, for reading stuff like arxiv pdf's.

I do know about epaper shelf tags but that is pretty niche imho. Not that many of us are involved in stocking store shelves.

Those look nice, and they are larger, but they're also 10X the price?

It's definitely the goto cheap MCU for me now, for one reason: it's in stock. It's nice that industry doesn't take it seriously.

I did think that drag-drop micro python (or is it circuit p) programming method was odd but maybe it's different now.

I personally am trying different stuff out. I've used Arduino/Teensy/ESP/Pi (OS) but I have a blue pill and beagle bone as well to mess around with.

The RP2040 does seem to have a lot of IO anyway.

You might look at the M5paper?

Esp32 based, so wifi, 4.7" eInk. I haven't used one, but it looks neat.

https://docs.m5stack.com/en/core/m5paper

I did look at that and it is interesting and kind of tempting. I want a lot bigger though. Thanks.

check ebay for eInk price tags. They are a great source of case+battery+enclosure+screen for $little

How much more power hungry is the dual-core Arm Cortex-M0+ chip vs. the ATmega328P?

At base clocks the mega will use half the power. Though unsure what gains you would recoup with the pico by reducing the clock, so maybe pico could match and surpase at a lower clock speed.

This is awesome, though I wish they would have used a chip with Bluetooth or WiFi.

That would eat through the batteries. Which means you likely need a different battery, which means more bulk, which ultimately changes the entire value proposition, and now you may have well buy a cheap android phone.

This thing, while worn requires zero power. You only require power to rotate the image.

Not really, provided the duty cycle is low enough. Espressif chips can be set up so that they boot, run some code and then shut down with a timer (deepsleep). You can stretch the battery quite far that way. I did this to monitor temperature in an outdoor pool.

Omega sell plenty of WiFi connected industrial sensors (with small batteries) that are specced to run for a year or so before a recharge. Usually they report measurements on the order of minutes.

I also have a Bluetooth HRM which I've used for years (probably days of use, cumulatively). I've maybe changed the battery once.

As someone who was working on a Wi-Fi connected e-ink display, you’d power down once you updated the display obviously.

This is awesome, saving for later

Nice work Jon!

already ordered

Very cool!

>Switch between images, pronouns or secret identities at the push of a button

Sincere question: is this poking fun at people using pronouns, or do some people change their pronouns throughout the day?

I know trans people that use different pronouns with people they haven't come out to and/or know are transphobic, but can't cut out of their life for whatever reason (ex: close family members). I've never heard of it happening at work, but say for example one of these people saw you in your work uniform.

Sounds like the easiest thing is to just...not include any pronoun? This has been a very old practice by now. Then there's nothing to switch, and you can use ordinary paper, which is much cheaper.

Not poking fun at anybody, just some different states that you may choose to display!

Yes, some people change their pronouns based on their internal state. These people will frequently self-describe as "gender fluid".

I believe it's just using those as example content to scroll through at the press of a button, but I'm now curious as well.

I took it as a list. Switching between an image (or series of images), your pronouns, or secret identities.

Some people do prefer different pronouns throughout the day. It's not common because it's difficult to communicate, but if it becomes easy to do then it may become more common and noticeable.

I read it as a playful joke that isn't necessarily poking fun at anybody. Is changing pronouns really any weirder than assuming a secret identity?

Well, it is, since "identities" of things (which from the language point of view are just designations of a referent, really) are significantly less fixed than a grammatical category. So changing it tends to be much weirder.

A use case could be a badge for guests, changing pronouns as needed.

Given that this has no e-ink color display, it is an instant deal breaker and a no buy I'm afraid and nearly reminded me of the old obsolete black and white Pebble screens (until they got E-ink color).

So from me, No thanks and no deal.

Along with White, Black and shade of black (greys), the technology is becoming mainstream with Red and Yellow color. We are using these for retail customers.

https://www.hanshow.com/news/194.html https://www.pricer.com/products/ (You can program with visible light too)

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