Digoo IP Camera Teardown and Links

I was just looking at unfinished posts and noticed that I’d taken, but not published, a bunch of notes I’d made earlier this year in hopes of hacking better firmware onto the Digoo BB-M2 WiFi PTZ Security Camera.I gave up on the quest, but here are my notes, with minimal editing.

Someone mentioned that the Chinese language page for Netcam360 has a link to the IPC-SDK. When I downloaded it and looked inside, I saw client-side code, but there was also a self-extracting archive called “HSmartLink Win32 SDK” and I remembered the PCB marking started with “HSL.” Searching for HSmartLink brings up hsmartlink.com, which, among other things, has IP webcams! The i9812 looks like a good match for my camera!

Unfortunately, no sign of any firmware updates. I checked the .cn version of the site too. It doesn’t seem as up to date on products (i9812 isn’t listed), and while there is more info in support section, it is still quite sparse. Page that looks like it is intended to link to downloads hasn’t been updated since 2015

Company is “Shenzhen Hsmartlink Technology Co. Ltd”

FCC Database listing for company

So what is the relationship to NetCam360 (check whois & IP ) and they mysterious APKLink?

Nmap Pobe

Starting Nmap 7.40 ( https://nmap.org ) at 2017-02-06 18:38 PST
Nmap scan report for
Host is up (0.0043s latency).
Not shown: 998 closed ports
23/tcp open telnet
81/tcp open hosts2-ns
MAC Address: E0:B9:4D:8F:61:6C (Shenzhen Bilian Electronicltd)

Nmap done: 1 IP address (1 host up) scanned in 0.49 seconds

Teardown Inventory



Module with Mediatek MT7601UN


  • 15UDN8WY, ULN2803AG 18Pin in 2-row SMD
  • Darlington Transistor Array: http://www.ti.com/lit/ds/symlink/uln2803a.pdf
  • Probably used for driving PT motors

Atmel 542

  • 24C02N, SU27D
  • AT24C02
  • Two-wire serial EEPROM (2K)

Vertical PCB

  • SF1810-002, www.sufeitech.com. PCB antenna?

oosilicon or dosilicon?


Balight 21W Folding Solar Panel USB Charger Partial Teardown

I picked up a 21W, 3-panel Balight folding solar panel-based USB charger from Amazon for ~$36 a couple of weeks back. It uses high-efficiency SunPower Maxeon cells much like similar 20-21W panels from AukeyAnker and dozens of obscure brands. All of them have the same basic construction. They are all made from nylon ballistic cloth. Each fold has a panel made from two SunPower cells encapsulated in a flexible waterpoof sheet. The panels provide power via two 5v USB ports, which presumably have some sort of voltage regulator.

I wanted to know more about how the chargers worked. In particular, I wanted to know if they were wired in series, or parallel because I wondered if it was worth trying to tap into the raw output, before the USB regulator to reduce power conversion and resistive losses for some applications.

I thought I’d be able to get the information I needed by finding someone documenting a teardown of their own panel on YouTube or a blog post. Despite the dozens of variants from dozens of brands and a handful of manufactures though, I didn’t find what I was looking for.

So, I decided to dig up a seam ripper and open my panel far enough to get a look at the wiring, and tap in to it upstream of the voltage regulator.

The panels appear to be wired together with some sort of woven wire conductor. I had some hope that all the cells would be wired in series, to give a nominal panel voltage of 18v. Based on what I could see, and measuring the voltage before the regulator in full sun, it looks like each panel is wired in series, for 6v nominal voltage, and then the panels are wired together in parallel. I was disappointed at first, but this arrangement makes sense in upon further thought.

Using a 2s3p configuration means that the input voltage into the switching regulator should be pretty close to the 5v (actually, 5.2v with enough sun and a light enough load) output of the USB power regulator, which will typically have higher conversion efficiency than 12 or 18 volts. It also means that the manufacturers can stock one converter for everything from a 7W single-panel charger, up to a 28w 4 panel charger without the converter having to support a wide range of input voltages. Perhaps most importantly, it means that partial shading of one panel shouldn’t have a disproportionate impact on the power output of the entire array.

The only downside is that resistive losses in the cabling will be higher with lower voltage and higher current, but that the interconnects aren’t more than a foot or so, the resistive losses shouldn’t be too high.

As for the converter itself, I may look at it more closely and add some more details, but, a few initial observations:

  • The PCB design has extensive ground planes on top and bottom, tied together with vias.
  • Both outputs are served from a single buck-converter (step-down) power supply based on a Techcode TD1583, which is a 380 KHz fixed frequency monolithic step down switch mode regulator with a built in internal Power MOSFET.
  • It looks like only port 1, at the top right in my photo, has the data lines connected, which suggests that it is the only one with fast-charge coding.
  • IC U2 looks like it has its markings sanded off. I notice though that one of its pins is connected to the enable pin on the TD1583, leading me to think that it is responsible for cycling the output to make sure devices draw as much power as possible when the panel voltage rises again after clouds or an object reducing the light falling on the array pass. I don’t know if it is a MCU, some sort of timer, or comparator, or what, though.

There you go. I can’t be sure that other folding solar arrays like this one are wired in the same way, but if they only support a 5v output, I suspect they will be. I hope this proves useful to someone besides me.

Monoprice MP Select Mini v2 Nozzle Replacement

I bought a Monoprice MP Select Mini v2 3D printer in late June. I recently decided I wanted to get some extra nozzles so I could have some spares, I’ve used straight PETG and PLA for most of my prints. I’ve also done some prints with 40% aluminum powder and 60% PLA, have some wood-filled PLA on the way, and I’d like to try printing with a carbon or glass fiber filled plastic too. These composite filaments can all wear the nozzles, hence my need for spares.

Monoprice doesn’t sell replacement nozzles, and nor does anyone else, as far as I can tell.  According the the community-made MP Select Mini wiki, the v1 and v2 use the same nozzle, which has a m6 threaded shaft, is 10mm from end-to-end, and 5m from the tip to the back of the nutted area. That’s what the wiki says, anyway.

The Wiki didn’t seem right to me. The most obvious issue is that the nozzle shown on the wiki has a different shape, like the photo on the left. There is a conical taper down from the diameter of the integrated nut to the end of the tip. After the nut section, my printer nozzle narrows immediately to ~3.5mm before the conical taper to the tip, like the photo on the right.

A bit of googling didn’t turn up any added details, so I decided to take out my nozzle and measure it with calipers. I pre-heated the hot-end to ~200C, adjusted a crescent wrench and tried unscrewing the nozzle. The whole heater block turned instead, so I grabbed some adjustable pliers, twisted the block back into place, and held it steady while I removed the nozzle.

By my measurements, the overall legnth of the nozzle is 11.5mm. From the back end of the threads to the flange for the nut section is ~6.3mm, and from there to the tip is 5.2.

Now I have to find something that matches those specs…