How I Built An Awesome Lightweight Off Grid Helium Miner

How small can you build an off grid min­er? Can every­thing fit in one back­pack? How light can that pack be? Final­ly, why would you want a tiny off grid miner?

And yeah, those are Pup­pies Make Me Hap­py sunglasses. 

Hey, before we go any fur­ther, please know that I’m NOT an elec­tri­cian, this is NOT pro­fes­sion­al advice, I’m just a dude who enjoys tin­ker­ing and build­ing things. Some of these com­po­nents, includ­ing but not lim­it­ed to the bat­tery & charg­er, can cause seri­ous haz­ard if not cor­rect­ly installed. Please find a local pro­fes­sion­al to help you exe­cute a safe deployment. 

I’ll start with the last ques­tion. Why would you want a tiny off grid min­er? The short answer is “weight”. If, like me, you are super stoked on the idea of hik­ing in an off grid min­er to a place deep in the wilds, you will even­tu­al­ly get over the idea of car­ry­ing in heavy equip­ment. I did that on my first off-grid, car­ry­ing in awk­ward­ly loaded 60+ lb rucks over 6 miles of rugged ter­rain with 3k’ of gain. 

It was the hard­est thing I’ve done since run­ning a hun­dred miles back in 2015. Fun once, and rad to share with a friend (we EACH had huge, awk­ward loads to car­ry), but not some­thing I was des­per­ate to repeat.

Still, being gen­er­al­ly unafraid of phys­i­cal work, I did the same thing a few more times, just to be sure it was­n’t just a one-time suck­fest. One off-grid took 6 (SIX!) trips in to install.

By that time, I fig­ured out that while I real­ly like hik­ing heavy shit long dis­tances out in the moun­tains, I’d prob­a­bly enjoy hik­ing in a light ruck even more. So I set about build­ing one. I also want­ed to re-mea­sure my ini­tial pow­er draws because I was see­ing off grid setups that seemed small­er with a high­er load..

After a con­ver­sa­tion with @BFGNeil on Dis­cord about using a Pi Zero and a RAK 2245 hat to put togeth­er just the pack­et for­warder (from a DIY Alpha code I received way back when they were still avail­able), I decid­ed to try it out. The enor­mous advan­tage of hav­ing just a pack­et for­warder (and not the full fat min­er) is the low­er data plan size I can use for the cell backhaul. 

I cannnot over­state this advan­tage. Please do NOT think you’ll be able to use a small data plan (100MB or less) on your pro­duc­tion Heli­um com­pat­i­ble Hotspot. You’ll need 50 GB MINIMUM, and will be much safer with 100 GB. I got lucky to find Heli­um right as they launched (and then quick­ly closed) the DIY pro­gram. This guide gives you an idea of what a Light Hotspot will be like.

One last note before we dig in. Off grids are hard, and com­pli­cat­ed, and some­times com­plex. If you just want to buy an off grid set­up, I’d start with IoT Off Grid. If, how­ev­er, you LOVE build­ing your own stuff, keep reading!

Let’s start with a gear list. 

PLEASE NOTE: This is MY gear list. It will prob­a­bly not fit exact­ly what YOU are try­ing to do. My goal is to have a tiny, light­weight, right-on-the-edge of pow­er require­ments for a Light hotspot in a high sun area. Make SURE you mea­sure your pow­er draws before just blind­ly order­ing what I used and think­ing it’ll mag­i­cal­ly work for your area. Your chal­lenges will be mak­ing sure you have enough pow­er and mak­ing sure you have enough data. 

The great news is that pack­et for­warders are what “light hotspots” will be, so it’s like­ly that you’ll be able to do this same thing and in a clean­er look­ing pack­age by mid-2022.

The sec­ond advan­tage of a Light Hotspot is the low­er pow­er con­sump­tion. Com­pared to a reg­u­lar min­er, with a pack­et-for­warder-only set­up you can shave off enough watts to real­ly drop both bat­tery size and solar pan­el size.

Here’s the pow­er it’s pulling. Note the size of that “hotspot”. It’s MUCH small­er than cur­rent pro­duc­tion hotspot, and pulls about ½ of the power.

Remem­ber, volts x amps = watts, so this is right around 1.5 watts. It jumps around a bit, but in any event, that ain’t much. 

Add in a cell modem and the solar charge con­troller with the pack­et for­warder on a Pi Zero and you’re look­ing at about 3.4 watts total. For com­par­i­son, a RAK V2 by itself pulls around 2.3 watts.

Want more data on pow­er draws? Here ya go!

Of course, it also depends on the win­ter sun hours in your area. If, like me, you live in Amer­i­ca’s Finest City (San Diego), you have more win­ter sun hours than just about any­one in the US. That means you can use a much small­er solar pan­el (30 watts is what I chose) as well as a small­er bat­tery (20 Ah in my case.)

I put those togeth­er in an enclo­sure with the pack­et for­warder, a small­er cell back­haul (IBR200 instead of the 650C I’ve used before, many off grid­ders are now using a Spitz), the same charge con­troller I’ve used, and had a tidy lit­tle package.

Still, you’re left with mount­ing the thing, which can be a real bear. The solu­tion I came up with was inspired by some­thing I saw over at MP Anten­na, plus the fact that I love to hand bend metal. 

I start­ed out with a sheet of 12″ x 48″ .0125 5052 alu­minum. 5052 is a good mix of tough­ness and rigid­i­ty. 6061 will crack when you bend it, and 3003 will flex too eas­i­ly. I marked out the holes for cut­ting and the lines for bending.

I want­ed to be able to mount this brack­et any­where, eas­i­ly. One of the chal­lenges of an off grid set­up is actu­al­ly mount­ing the thing. Though you can’t see ’em in the above pic, the lat­est ver­sion has slots for worm dri­ve (hose) clamps as well as the screw/bolt hole mounts you see here. This will eas­i­ly mount to a round object, like a pipe or a pole or a tree. It’ll mount to a flat sur­face as well, like a rock wall or the side of a building.

Next up is drilling & cut­ting ’em out. Alu­minum is pret­ty easy to work with, which makes this a nice project.

Next up was cut­ting the “win­dow”, which allows you to reach in with a drill and mount on the back holes before putting the solar pan­el on. Here’s the plate drilled and cut, ready for bending.

When I go into pro­duc­tion (that’s a joke, by the way) I’ll use a press brake and water jet, but for pro­to­typ­ing you can’t beat a bar clamp (as long as you don’t mind a lit­tle phys­i­cal work). You put the plate in the bar clamp, make sure your bend line is straight, tight­en every­thing up, and start ham­mer­ing. Hand bend­ing takes patience; you don’t see a lot of progress at first, but over time you’ll end up with a beau­ti­ful­ly bent line.

As you can see, I set up a lit­tle card­board angle mea­sure­ment device which gives me an angle of 148, or a 32 degree bend. 32 is our lat­i­tude, and gives your solar pan­el the most sun rays dur­ing the short­est days of the year. Here’s what it looks like with the first bend finished.

From there you just slide the plate up and ham­mer out a 90 degree angle. I’ll usu­al­ly go back and forth a few times with the bends. On a press brake you don’t need to, but when hand bend­ing I always find a lit­tle extra love makes for a clean­er job.

It’s not uncom­mon to have “extra” bends in there, which you’ll need to flat­ten out on an anvil. In this case the “roof” had a slight arc to it. I leap at any chance to use my Nim­ba Titan, here she is ready to assist in the flat­ten­ing process. Man, the right tools make the job easier!

All that ham­mer­ing attract­ed my wife’s atten­tion. She knew the best fuel for any endurance event is the cake from Paleo Treats, so she brought some out. Damn, that Key Lime is good!

Fueled with cake and ready for the next step, I assem­bled the box, the pan­el, and the antenna. 

This next part may be con­fus­ing, as I’m using pic­tures from a few dif­fer­ent builds here. The parts you see in this build on the inside of the enclo­sure are the RUT240 cell modem (NOT the IBR200), a Ren­ogy Wan­der­er 10, and a Bioen­no Pow­er 20 Ah LiPoFe4 bat­tery. The hotspot itself is a Pi Zero cou­pled to a 2287 con­cen­tra­tor and Pi hat from Par­ley Labs. 

Here’s just the RUT240 and the DIY Hotspot.

I print­ed up lit­tle red PETG brack­ets for the RUT240 and the Pi Zero on my Prusa 3D print­er. At about $800 for a kit, they’re a very use­ful thing to have if you get into this off-grid world.

If you don’t have (or want) a 3D print­er, go to the Prusa World map page and look for folks near you who are will­ing to print them up for you. That’s how I did my first 3D prints. Here’s the Pi Zero nes­tled into its brack­et. Brack­ets make it very easy to attach com­po­nents to the “perf board” that comes with most enclosures.

Wait, you want every­thing labeled for ya? No prob:

Here it is mount­ed on the near­est avail­able space (my work­bench) as a test run. Please note that you’re not lim­it­ed to mount­ing on workbenches. 😉

The box still needs vent holes cut and vents mount­ed along with the holes & glands for anten­na cables, but this gives you an idea of how the thing works. It is WAY eas­i­er than any oth­er off grid mount I’ve built. Here’s a quick video of it with the HNTen­na and a cell anten­na mount­ed, though no cables run yet.

The next step is break­ing it all down and see­ing if I can fit it in my back­pack. One of the real beau­ties of this set­up is how small it is. Most back­packs on the mar­ket are way too small to fit a large enclo­sure. This back­pack is built for elk hunters to car­ry out their meat, but I fig­ured Stone Glac­i­er would­n’t mind if I repur­posed their EVO 3300 as a telecom­mu­ni­ca­tions pack. To be clear, this is not (by far) the cheap­est pack you can buy to do this job. I just like nice things.

From left to right you’ve got the pack, the solar pan­el, below the pan­el is the HNTen­na, then the enclo­sure with a GK tool roll on it, and final­ly, the bracket.

Now, that brack­et has some sharp edges, so if you’re going to strap it on a pack you’ll want to cush­ion those. I had some left­over foam lay­ing around the shop, so I taped it on with painters tape (comes up off eas­i­ly) and set up the pack.

You can’t see it in that pic, but I’ve also padded the solar pan­el, which is against my back in the pack. While the pan­els don’t scratch super eas­i­ly, they’re not the tough­est thing out there, and any scratch can decrease the effi­cien­cy. That’s some­thing you want to avoid when you’ve got such a small pan­el. Here’s the pack with every­thing in it, all ready to go.

I’m guess­ing the whole thing weighs less than 35 lbs. If you’ve ever got­ten into pack weight and how it can effect your abil­i­ty to per­form under pres­sure, you know that this is right at the lim­it of what saps courage over time. I’m not expect­ing to engage in any fire­fights while mount­ing this thing, so I feel pret­ty safe, even if I’m slight­ly over S.L.A Mar­shal­l’s rec­om­mend­ed weight.

After load­ing the pack up I decid­ed to re-wrap the brack­et with a clean­er look­ing foam set­up using pipe insu­la­tion. Here’s what that looks like, just for reference.

The gear is pret­ty straight­for­ward (aside from the brack­et). This is a slight­ly dif­fer­ent set­up than the one I’ve shown you. Try to iden­ti­fy the com­po­nents on your own, hit the com­ments if you need help.

IBR200 cell modem, Ren­ogy Wan­der­er charge con­troller, 12–5v buck con­vert­er, and then what­ev­er your hotspot is. Here’s the inte­ri­or lay­out with almost noth­ing hooked up. The two pink/orange cables go out to the cell modem anten­nas. You can see the vent up at the top right. There’s also one at the bot­tom left. Because the PiZe­ro does­n’t have a native Eth­er­net con­nec­tion I picked up a con­vert­er for it. Every­thing else is pret­ty straightforward.

If you’re look­ing to do this same thing, keep in mind that this enclo­sure may NOT fit your hotspot, at least as I cur­rent­ly have it laid out. RAK V2s will be fine, but oth­er hotspots may need to be mount­ed on the door, or just require a reshuffling.

Ok, that wraps up most of the details on this project. If you’d like help get­ting your Heli­um Hotspot off grid, con­sid­er hir­ing me to walk you through the best ways to both build and place your hotspot. Rock on!