After getting my first Helium hotspot and researching more about the technology I decided to get a second hotspot. But the issue became how to get one, as it can take months to receive one after a preorder. So there is substantial risk in the purchase. My first hotspot took almost 5 months and I only pulled the trigger on the purchase since it was through Sparkfun.
So I was very hesitant to purchase one of the Bobcat or RAK devices since the lead times were very long. That is when I heard about the SenseCAP M1 hotspot, which was being built by Seeed Studio. Seeed is a manufacture of DIY electronics for hobbyist use similar to Sparkfun or Adafruit. I decided to go for it as they were planning on doing direct sales of the first few thousand hotspots. This means that there was no preorder as these units were already built.
There was still a significant hurdle to overcome, potential buyers needed to first purchase a coupon code with Helium cryptocurrency HNT. This meant waiting in an online queue and sending the required HNT from the Helium app. Thankfully I already had a wallet set up and enough earned HNT for the purchase. I missed the first set but the second I was able to acquire the coupon code!
Once I had the code the massive influx of people trying to buy the physical devices through the Seeed Studio website ended up crashing their webpage! so it was another tense few hours before I was finally let in to complete the purchase.
All in all purchasing nightmare but fast shipping but I’m not sure id put myself through that again. Now new orders are through a preorder system that states shipment in November but that could always be pushed back by COVID delays. So make sure you understand the risks before purchasing.
Seeed Studio SenseCAP M1 Pre-order
Hardware
Ok now back to the main program! After receiving my Nebra Hotspot with parts rattling around in it, I was pleasantly surprised at the SenseCAP packaging and build. Opening the box we can see a Helium setup instruction card. Under that, the Hotspot and its accessories were nestled in soft protective foam.
Taking out the Hotspot the all-metal enclosure is extremely ridged with ports cut out for the antenna, USB-C power, ethernet port, and a plethora of cooling vents. This is important as the raspberry-pi-4 that powers the board can get quite toasty. On the underside, we can see an active cooling fan to help with airflow which is severely lacking from my other miner.
The only thing left in the box was the antenna which I tested on my trusty NanoVNA V2 to see how good the stock antenna was matched to the 915MHz frequency that Helium uses in the US.
From the results, we can see that the antenna is not spot on but provides decent matching with an S11 of -18db of return loss. The NanoVNA V2 is mostly used to get an approximate measure of the antenna as it’s not lab-grade test equipment.
Software
The hotspot uses the Helium App for setup so the process is really straightforward. Just download the App from either the iOS or Google Play app stores onto your smartphone. This will also act as your wallet that your Helium mining rewards will be deposited into.
In the near future, SenseCAP will provide a remote management service that will allow you to perform maintenance operations or check status remotely. But it is not yet available at the time of writing this post.
Outdoor Antenna Installation
The first thing I did once I decided to get another hotspot was scout the potential location. I did this using the HotspotRF simulation service which allows you to quickly get a good idea of a hotspot’s RF propagation based on the location topography. From this, it looks like there are about 9 hotspots that should be able to see my hotspot and communicate for proof of coverage.
If you are curious about how this works I created another post that details the HotspotRF service and a bit about RF propagation in general. Check it out below!
Time for the install! This was my first time installing an outdoor antenna that was not just right outside my window so I was a bit unprepared for the task. I wanted to get the antenna as high as possible but did not have the correct ladder to get all the way to the Chimney to mount it. So I had to settle for a lower elevation that was also a bit blocked by the house, not ideal. From there I screwed the mount into the roofline wood and attached the antenna to it. I then installed a lightning arrestor and the low loss N cable to the antenna. I was able to snake the cable down a drainpipe and around to a window. Using a trusty window jumper cable I was able to easily get the cable inside to the hotspot.
I used a simple metal stake and some simple metal wire to ground the lightning arrestor for protection. This will be even more important once I can elevate the antenna a bit higher. I was not able to get ethernet to the hotspot but the wifi is working really well so far.
I also checked the outdoor antenna matching with the NanoVNA V2 before and after the installation to make sure it was a good match for the 915MHz frequency band.
Before Install 
After Install
From the before and after images we can see that the longer feed line used to connect the outdoor antenna introduces a bit of noise to the measurement but is similarly matched which means all of our connections and cables are good.
After I had everything set up It took about another 10 hours to sync up to the Helium network and begin receiving rewards.
Proof of Coverage Results
The ultimate goal of setting up a hotspot is to provide Proof of Coverage which is the algorithm behind the Helium reward distribution or how much of the HNT crypto-currency you make.
Discovery Mode
Once the hotspot syncs to the network we can perform a simple test in the Helium App that sends out a signal to see what other hotspots you can potentially talk to. This is called “Discovery Mode”, the results are shown in the left image and the right is the hotspots witness list after a few days. So it gives you an idea of potential hotspots but is not guaranteed representation of the witness list.
Rewards
Over the 9 days that I had the hotspot online, it made 4.17 HNT, which works out to about 0.5 HNT per day. Not great but still earning in the post-halving environment.
The main issue seems that the combination of my antenna and the nearby hotspots antennas creates an environment where the SNR of the witnesses is too high for the received RSSI. This is a common issue that will be fixed in the POCv11 update. More info on this can be found at the post linked below.
If this rate stays the same and the HNT maintains its current price it would take me about 2.5 months to get a return on my investment not too bad! But I also plan on increasing the height of the antenna to reach more hotspots in the area.
Conclusion
I was really impressed by the build quality and quick shipment of this hotspot by Seeed Studio and wish more manufacturers would take from their example. The use of a full raspberry-pi-4 and the use of a smaller integration PCB for the LoRa concentrator is somewhat of a double edge sword. it was quick to make but could experience delays if the pi boards become hard to acquire. I was also surprised how easy it was to set up even with the antenna install taking the lion’s share of the time. I just let the hotspot start syncing with the included antenna while I was working on the outdoor one. This is definitely the hotspot to beat. If have run the numbers and have weighed the risks it’s a good little device that just works!
Check out my other hotspot set up below if you are itching for more Helium content!
Also, check out Crypto.com if you are looking to trade HNT as it has become my go-to exchange for the simplicity of use compared to my old method and Binance.
Extras
Once you do get your hotspot up and running consider checking out Hotspots Health which combines a dashboard interface with a performance analyzer to help you get the most out of your hotspot.
