Info on hacking a kankun Atheros-based wifi socket running OpenWRT
Source: kankun – How to Linux
Info on hacking a kankun Atheros-based wifi socket running OpenWRT
Source: kankun – How to Linux
More info on local control of Orvibo S20 Socket
Good info on hacking/spoofing the Orvibo S20 WiFi socket. Unfortunately, it appears that the security of the cloud service is (was?) really bad.
Report on using Sonoff with alternative Sonoff-Tasmota Firmware
Source: Review of Sonoff RF Bridge, Sonoff 4ch Pro, and Sonoff POW with Sonoff-Tasmota Firmware
Code to allow OTA installation of alternative firmware on Sonoff devices, avoiding the need to connect to the serial port.
This looks super-useful.
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”
So what is the relationship to NetCam360 (check whois & IP ) and they mysterious APKLink?
Starting Nmap 7.40 ( https://nmap.org ) at 2017-02-06 18:38 PST Nmap scan report for 10.31.1.124 Host is up (0.0043s latency). Not shown: 998 closed ports PORT STATE SERVICE 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
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 Aukey, Anker 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:
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.
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…
I noticed that Banggood just listed the H&V HV-50 TDA 7492 Class-D amp on their site for $59.99 with “Priority Direct” shipping to the US from China. This reminded me that I’ve been remiss in posting anything more about the HV-50 amp I ordered on eBay last summer for ~$35.
After ordering it, I was a bit worried I’d been scammed, because the seller never provided any tracking information, but those fears were quickly laid to rest when it arrived on my doorstep all the way from China in just 9 days!
Some details from my earlier post on the HV-50:
The TDA7492 chip is used in a lot of compact, inexpensive audio amps made by various Chinese manufacturers and sold under various names on Amazon, Ebay, AliExpress, etc.
One such amp is/was the very similar looking SMSL SA-50 amplifier, which puzzled me, because when I first found the HV-50 listed on AliExpress, the seller listed it as an SMSL product. It wasn’t until I had it in hand that I realized that the eBay listing didn’t mention SMSL and there was actually no reference to SMSL anywhere on the product, or or the very thin users manual.
With some digging though, I found persuasive evidence that H&V is/was a new brand from he same company that produced SMSL. Given the price point, and product photos of the HV-50s internals, which showed signs of cost cutting, I assumed the H&V line would be a new, lower cost line, as SMSL seemed to be moving upmarket. Positioning the HV-50 as a lower cost alternative to SA-50 or A2 amps made sense when the HV-50 sold for $35-40, while the SA-50 & A2 were selling for roughly twice that. It makes less sense with the HV-50 selling for almost $60.
Looking more closely, the SA-50 seems unavailable from Chinese sellers on AliExpress and eBay these days. On Amazon, it sill goes for $60-70. The HV-50 seems to be in the process of being superseded. Aoshida, the source of my original amp seems to have both an eBay and and AliExpress presence. On AliExpress, they have a listing that pictures an HV-50 with a 24v power adapter for $42.28, shipped, but the listing is actually for a “TOE F1 TDA7492 amp” and notes that the housing may say HV-50, but it’s been “upgraded to TOE F1.” Their eBay store has a very similar listing, also for a “TOE F1 TDA7492 amp” for $53.00.
I think the HV-50/TOE F1 is a pretty good deal at $42 shipped with a power brick. At $50-60, that’s less clear. I’d probably pay another $10-15 for an SMSL SA-50. The reason? If the SA-50s shipping today are the same as those shipping a year ago (not a sure thing, given that SMSL changed the guts on the SA-36pro without warning, explanation, or acknowledgement) then they use some high quality film capacitors in key parts of the audio path.
On the other hand, the HV is clearly a cost reduced design, as I suspected from the initial product photos, and confirmed upon receipt. It uses SMD ceramic caps for all but the main power supply caps. I personally think the cheaper caps work well enough. I don’t have an SA-50 to compare the HV-50 to, but while it’s possible they would sound obviously different, I doubt the SA-50 sounds noticeably better. For $30 less than the SA-50, I think the HV-50 is an obvious choice for those on a budget. For the current $10-15, price difference, it is much less clear cut.
What remains to be seen is if the TOE F1 is actually an upgrade, and if so, in what way? Will they adopt the film caps used by the SA-50?
When powered up, a tiny click may be emitted from the connected speakers.
I noticed no obvious defects in sound quality. My main complaint is that the design & construction of the PCB-mounted RCA inputs doesn’t make good solid contact with the slotted, machined pins on some higher-quality RCA plugs, leading to noise or audo drop-outs. At first, I though the volume control pot was going bad. I ended up replacing the jacks with some gold-plated panel mount jacks with better design/construction. Interestingly enough, while the original part has trouble with higher-end RCA plugs, it has no problem at all with inexpensive stamped & rolled RCA plugs.
Speaking of connections, the speaker output binding posts are small, but work well with banana plugs, spade connectors and properly trimmed and stripped speaker wire (to avoid shorts).
There are a few important caveats about the HV-50, which may or may not apply to the TOE F1:
First, it’s important to understand that the generation of class D amplifier chips like the TDA7492 used in the HV-50, along with the more powerful TDA7498, and the comprable TPA3116, all have consistently inflated power ratings. These ratings are often used in the specs of cheap amps built around such chips.
The inflated ratings aren’t exactly inaccurate, its just that they only apply under unlikely listening conditions. They assume a power supply voltage near the top of their operating range which ends up being 24v for the TDA7492 and TPA3116. This isn’t an issue with the HV-50, which comes with a 24v supply, but can come into play when using ~19-20v laptop adapters. The tests are often performed with ~4 Ohm loads, while lots of home audio speakers are closer to 8 Ohm, and peak power output would be ~50% of the advertised number. The finally issue with the ratings is that they allow up to 10% distortion, a value that most people will find unlistenable. Values are generally also given for up to 1% distortion, which most people will find suitable. The corresponding power ratings are ~50-60% of the advertised value.
In sum then, the usable power of the HV-50 and similar amps with a suitable power supply is 50W * 50% (for 8Ohm speakers) * 60% (for reasonable distortion levels), which works out to 15w/channel. This may seem much less impressive, but it should be enough power to push most consumer bookshelf speakers close to their (and your) limits.
Second, the HV-50 does not, as claimed in the Bangood listing and elsewhere, contain parts from EPCOS, Philips, ALPS, DALE, etc. The volume control pot seems like a cheap, but adequate generic Chinese part, and the capacitors in the audio path are all SMD ceramics.
Bottom line: The HV-50 is a decent, inexpensive Class D amp if you can get it shipped with PSU for ~$40. Whether it is a good choice vs an SA-50 or similar really depends on the price difference at current market prices.
And finally, the main purpose of this post wasn’t writing a wall of text, it was sharing photos of the guts of my HV-50.