Lantern Feature Requests

Hardware and software feature requests for Lantern

So doing a lot of international development work and some ICT4D work I’ve got some thoughts for lantern. Figured I’d share my requests:

  1. Replaceable batteries reduce ewaste creation, please make the battery user serviceable. Otherwise in 4-5 years you have just another hunk of e-junk that has no proper disposal stream in an emerging market.

  2. Make a custom user content section. This would be some kind of file repository for a local group/school/organization to upload their own documents. It needs a fileserver if it will be the main wifi people are connected to at the basecamp/school/etc.

  3. Add an SD (full or micro) slot for expansion and transfering locally shared files.

  4. Use standard USB charging connectors (unless you are gonna waterproof it, though there are ways to waterproof with the USB slot happy to talk through how to do this).

  5. Making it at least rain proof is important

It has solar panels and external charger.

This is a Librarian feature, and it’s on my TODO list.

It will have SD card (possibly two, one for the OS and another for user content).

I think some weatherproofing will be in the final design, since it’s meant to be used outdoors as well as indoors. Not sure if the charger port will be weather-sealed though. It has solar cells which are meant to be used outdoors instead of a charger. I’ll have to look at the draft specs again before I can confirm, though.

Yes, it has… But the point would be to have a user serviceable battery that can be procured and replaced easily. This way when the battery eventually loses the ability to hold charge, the device is not rendered useless, rather new battery would extend its lifespan. Not putting in a user replaceable battery is a conscious decision to build in planned obsolescence. The way to go about this would be to find a popular mobile phone(like Nokia used its phone batteries for Bluetooth speakers for example) that has a replaceable battery and implement that battery. Mobile phone batteries have large capacities and are easily obtainable, either as originals or as aftermaket models.

Now, I have a few feature requests as well:

Make the usb connection function as a network adapter, like android does when usb tethering is enables. This can be demonstrated by installing app such as airdroid, and connecting the phone to the pc via usb, with usb tethering, while leaving the WiFi off. The phone will show up as a network adapter(via USB) and the airdorid app would be accessed via web browser as if it is connected over ethernet.

This would be especially important in situations with censorship as WiFi emits RF waves at 2.4 or 5 GHz bands, and is interceptable. The other reason would be reduced power consumption of a laptop and the Lantern(especially important when away from the power grid.

Implement an e-book library(download epub) with both web interface(for PC, Mac and e-ink readers with web browsers) with client software for android and iOS. There are some really cheap android tablets that can be used as ebook readers. The Lantern would be a server, and handheld would have and app that would allow synchronization, much like iTunes over WiFi. This would allow a single lantern to literally serve as a library for a village.

This one is not Lantern specific, but do try to get some useful content and books in Serbian! :smiley:


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I’ve taken a look at the proposed specs and there’s mention of 4 AA batteries being used as option in addition to solar panels.

Yes, this is also in the proposal.

Would being able to download an e-book from Lantern not suffice?

Know any? :wink:

Thanks for a quick reply! :smile:

I would still prefer to have the main battery user replaceable. Everything else is just a hassle, IMHO of course.

How about building the device around… lets say a Samsung Galaxy S3/S4 battery? High capacity, low volume…


This proposal is for the purpose of multi-user use case scenario. And also, keep in mind that many people who might benefit from access to ebooks are not fully computer literate and might encounter issues in managing libraries(book collections) on their devices. Also, this would make extra sence for iOS (example, older iPod touch is relatively cheap, but file management in iOS is [bleeeeeep!!!]. )

Freely available? Very few, but I’d be happy to try and lobby for older editions that are not in print any more to be donated. (yes, I know, fighting windmills and such). It would be really nice if educational material would be available in Serbian. There is a lot of bright people all over Serbia that just doesn’t have access to knowledge.

Knowing the situation, I can only say good luck with that. :smile: Of course, addition of resources in any language is always welcome.

[The way to go about this would be to find a popular mobile phone(like Nokia used its phone batteries for Bluetooth speakers for example) that has a replaceable battery and implement that battery.

This is a good idea. The most popular phone in Africa is the Nokia 5130, which uses a BL-5C battery, so there is a good case for using that. You could ship it with the 2450Ma version, whilst allowing user replacement with the more common 1020Ma version.

Due to the size of the market there will be batteries available for many years to come: In the UK & Uganda

Just going to re-iterate the importance of the user replaceable battery. Emerging markets are littered with dead solar powered lights procured by aid agencies from China. Some of these are very well known brands. I had a friend who sold a few thousand of a very popular solar light bulb in Haiti. 30% of them were dead in a year. Cause - 8 times out of 10 bad batteries, 2 times out of ten bad capacitors. This stuff gets by your QC. On those units his team was able to take them apart and fix them because they were designed to be user servicable. Plop in a new batetry and they worked great.

On the weather proofing from an ID perspective there are 4 common ways to do it:

  1. Headphone jack usb connector (this is bad because it is non standard but you can go scuba diving with it - overall nonstandard cabling =crappy in emerging markets)

  2. flimsy little rubber covers (these always warp over time so they don’t seat well after a couple years, this means the device isn’t weather proof anymore)

  3. flat screw down lid with a rubber gasket - you keep all the connectors and user servicable battery behind this lid (you see a bunch of Garmin and other satelite stuff take this approach, makes it water proof but sucks for regular charging in the field if you don’t have jewelers screwdrivers or you lose the screw to the cap in the dirt)

  4. Screw on cap with gasket and lanyard to keep you from losing the cap (my preference, make the entire bottom a screw on cap with a gasket and a lanyard exposing the battery changing, SD, and USB ports. You can do the ID with a little divot so it can still stand when the USB cable passes through so you don’t have signal problems if charging). Happy to draw this option in Solidworks if you want, but consider it. It is pretty straight forward to produce from a manufacturing perspective, and it can make it 100% waterproof very easily.

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As far as I can tell based on the initial proposal, the device will have a charging cradle. Solar panels might not even be on the Lantern’s enclosure, but on the cradle. The cradle is used to charge the removable battery, not the device. Solar panels might still be on the Lantern in the final design, but it depends on the cost.

Lantern may use one of the following removable/interchangeable sources of power:

  • rechargeable battery charged on the cradle (that comes with the cradle? I have no info on what battery would be used)
  • battery pack with 4 regular or rechargeable AA batteries
  • car battery 9~15V (with some kind of adaptor that slides into the battery pack slot?)

These power sources are connected or installed into the same slot on the device.

Additionally, it will have a microUSB port for getting power.

This is what I have for now.

As for weather sealing, it’s not a pripority item in the first iteration so, it may be implemented only if cost allows.

I like the idea of not having a battery in the lantern at all, or at least having the option of still using, it directly solar powered once the batteries have given up.

Based on the size of the panels in the visualisation I reckon you would get at best about 400Mw from them on a sunny day. If this is enough to directly run the the UHF receive radio and save the data to the card that sounds like a success. At the end of the day I can pop out the SD card, put it in my phone or laptop and view the data.

So my feature request is to be able to bypass the battery (if you do put one in the actual device) and run it directly off the sun on a sunny day. If the battery is a required part of the circuit then once it starts to die it will just eat power and make it impossible go get data using just the solar.

In the above scenario you’d need to sort out your own 5v external power if you wanted to use the WiFi as it’s quite power hungry.

It seems to me that the clever bit of this device is that it can get me data from space, getting the data the last 5meters is just a convenience if I can pop the SD card out. It seems mad the last 5 meters is going to use a similar power budget to the first 2000 miles.

I’m wondering if you had considered bluetooth as an additional option to WiFi which uses much less power? I think it would also allow you to use Africa’s most popular phone the Nokia 5130 which has Bluetooth but no Wifi

If you go with a removeable rechargable battery, you’re going to reduce the problem to an existing solution. You’ve got rechargeable AAA NiCad (or LiON) batteries available retail. There are commercial solar battery chargers in the $15 - $50+ range.

Charging batteries off-system means that 1) you don’t have to worry about charging while using the system, 2) you’ve got spare / additional batteries that can be swapped rather than disabling the Lantern entirely while it’s recharging, and 3) you’re disaggregating the storage-and-charging functions from the Lantern functions themselves. Batteries (and charger) can be provisioned and/or replaced independently of the Lantern.

Costs of extant chargers may also be a useful (and possibly sobering) point of reference for the affordability of such technology.

A couple of items from Amazon:

Some of the smaller / cheaper systems strike me as unlikely to provide effective / acceptable performance. The Anker 14W charger ($60) is more in line with the specs I suspect you’ll be aiming for.

The form-factor of the Lantern itself is not amenable to much charging. If you flattened the design you’d improve it slightly. I estimated total volume at about 100 cc, at 2.6cm x 2.6cm x 15.25cm. If you change that to 0.5cm x 10cm x 20cm you still have 100cc internal space, but have increased the sun-facing surface area from 38 cm^2 to 200 cm^2. I’ll assume high-efficiency 25% PV cells, that gives a maximum of 5W continuous, say 30 Wh per day if you expose the Lantern to 6 hours of sunlight. The 14W charger would gain 84 Wh over the same interval.

I say off-board charging FTW.

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Yeah, it looks like that’s how it will work, at least in the first iteration.

I think you make some good points

that gives a maximum of 5W

I’d say less than that, probably more like 1W @ 5v in the real world.

3) you're disaggregating the storage-and-charging functions from the Lantern 

It seems to me there are two separate ‘modes’ to the device.

  1. Grabbing data from space approx 0.5w @ 5v

  2. Providing data over Wifi to local devices: additional 1-2w

We have established that given the form factor (or budget) it’s not possible to build a in built solar/battery system that does both satisfactorily.

However I do think it could do 1) directly solar powered, for much of the world, for much of the year. Making the device direct sun powered would involve putting a capacitor in it and a simple circuit to boot the device when enough power is received & shut it down cleanly off the capacitor when voltage grops.

So install 1w of panels @ nominal 8v, set the device to boot at 6v & shut-down at 4.5v.

Then put a usb socket in the side of it for external power and people can sort out whatever solution they want for 2) (including not bothering and swapping the sd card between lantern and phone)

Robust solar power systems are a well understood technology. I’d suggest a partnership with people who already do this would make sense, rather than trying to fix both the ‘data from space’ & ‘remote power’ problems at the same time

I’m a fan of: & think they’d make a good partner.

Standards for lights/ charging stations are defined:

Discussing Outernet at work the other day, as I do quite often now, someone commented that if the ORx needs off grid power, i.e., solar, how are the users powering their WIFI devices?

ORx is not the same as Lantern. As for Lantern, iirc it would have a battery pack that is solar-charged, not solar panel on the device itself.

I see. My bad, I was thinking lighthouse, but its lantern feature request!

Lighthouse does not have an off-grid power option.

Put me down for replaceable batteries, as well. I envision having Lantern in a hiking scenario where I will be carrying a solar charger and rechargeable batteries so having replaceable batteries in a long term survival situation where I can access survival guides will be invaluable if the factory batteries ever conk out.