maketronics

[maketronics]

Fixing an IKEA Sunnan lamp today. Someone put normal Alkaline batteries into it a few years ago and that obviously didn't work out. After cleaning out large amounts of crystalline acid, I could put in the new rechargeable NiMH2 batteries.

Very simple repair and also very simple electronics? Just what looks like a single ADDTech A705 led driver and a diode? Any solar current goes straight into the batteries. Once turned on, the A705R driver makes the suitable current?

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My super-nice PreSonus Eris 3.5BT speakers just died. 3 years old. Not very good quality? Power stage is dead & hard to replace since it's custom & integrated with amp.

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Third defect old speaker I'm tearing down this Christmas. This one is from Australian bits'n'bob store Smiggle. Extremely simple and quite cleverly made?

Kinda funny and Egg shaped speaker that you twist to extend a white flexible tube. Inside is an self cycling RGB LED that makes it look flashy and more advanced that it actually is.

The Egg has a big counter-weight at the bottom so it won't tip over. Makes it fun to play with. Decent size LiPo battery, but there is absolutely no charging circuitry here? Just a diode that drops the 5V, so this thing might be a fire hazard unless there's some protection inside the LiPo. Cutting the battery open where the wires go in does reveal a small protective circuit, but this is very "bare bones". A study in how cheap you can make electronics?

The PCB itself is extremely simple! Single layer with the TI LM4871 Boomer - a simple 3W amplifier. Only the LED is on the back. But where is the audio input??? I analyze the circuit and understand that it is using the Data plus and minus pins as the audio inputs.

Poking around on the web, I find a picture that shows how this worked. They used a custom cable that basically hacked the USB cable and replaced data with left/right channels from the phone's audio jack. Clever!

Also interesting to note the high count of custom moulded plastic parts. No less than 7 for such a tiny thing and two of the parts are printed on. Plus the metal weight at the bottom also looks to be custom. Quite complex for such a cheap little thing!

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Another old speaker that the kids left behind - the classic MusicAngel!. You could daisy-chain multiple of these with a cable. This one is also not working due to a fully discharged battery.

This one is packed so thightly and all parts glued in, so impossible not to rip the speaker wires.

Pretty sure this one would live as well if it got a new battery! This one is MUCH simpler singe it's a wired speaker. All it contains is the PT5326 - a 2 watt amplifier with some passives. Amazing that they could sell that many thousands of this device given how simple it is?

It's interesting to see how the bass-reflector works here. It's not active. It's just something for the main speaker to kick off from. Not impressive bass by any means, but it adds to the expense so it must be worth adding.

[maketronics]

One of many Bluetooth speakers in our house that no longer work.

Disassembly is easy. Just remove the rubber underneath to reveal the screws. The main chip is the OVC3860. Very capable thing that even has serial control. All looks fine, but the battery is 100% empty.

Adding a similar (single cell) battery I found in a drawer. It had just 0.2V left but that got it working & the battery charging. Sad how so many LiPo devices don't include protection from a full discharge? Without that, they're electronics trash if you forget to charge them for some months...

[maketronics]

Disassembled one of my first LIFX lamps when it broke - after 10 years of service. Not bad? Very easy to get access to the wireless control board. Just pop the plastic lid off. The lid is color matched to the aluminium heat sink casing.

Custom and unmarked chips dominate the board. Rf squiggly antenna right on the board.

The LED driver board is kind of as expected- with RGB LEDs strewn around and a ring of 8 LEDs that looks like Osram OsloN?

The high voltage driver is slid into the heat sink. No easy way to get at the electronics as it’s completely potted. That can’t be good for heat dissipation?

Overall, a very solid design but it seems to be very labour intensive to put together?

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The very disappointing LED system of the designer “Soy Lamp”. A puny 3W system that is unable to shine light through the tail of the fish, making this just an extremely expensive mood light. We ripped out the internals to replace it with something better…

Contains a 2k FT24C02A flash chip, a beefy N-Channel Mosfet - both of these are too big for its application, but they’re cheap on lcsc.com. There’s also a tiny 8 pin micro, but it has no markings. So simple. Can’t have taken much time to design? Why didn’t they just make this much brighter, so it was more useful?

[maketronics]

Disassembled an IKEA dumb-bulb. Not much in here others than rectifier, transformer, diodes and lots of caps…

[maketronics]

This is the ATmega32U4 chip on an Arduino Micro. A friend told me his Arduino didn't work. Can you see where the magic smoke escaped?

[maketronics]

More closeups of mystery antenna part. It is the size of the U.fl connector, but has no center pin for an antenna to attach to. It is also normally hidden inside a plastic casing, so you wouldn't be able to attach an antenna even if you wanted. Pic #2 shows how there is one on each side of the board.

[maketronics]

My old DLink wifi dongle died, so I swapped it for a new & faster + took it apart. Nice mechanical design and some curious components? Never seen that golden thing that must be the antenna & several somewhat colorful passives.

[maketronics]

Testing some soldering kits for possible use at Bitraf. The Dice was terrible. It can only roll 1, 3 or 5, so not very useful or fun. The Beetle is very cute. I'm very sure we'll use that for kids workshops. The last is a function generator with a fixed 960 hertz output (so also not very useful). That square wave doesn't look very square to me? I thought it could be used to test during Oscilloscope workshops, but with this quality it's of no use. Oh well. Good fun to solder them all!

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Testing tiny speakers tonight. The black one on the middle is just insane! Despite its puny 16x9mm (0.63x0.35 inch) size, it will output 70dB when powered from a AA battery? It's actually so loud one of my kids complained. At just $1.30, I think this one from CUI Devices will go into the kit I'm making.

[maketronics]

Looking at the cost of an IoT device today, so I'm doing a teardown of the $39 Smarter FridgeCam. Based on the contents, I cannot understand how they make any money from it as it's selling for less then the cost of the components. Also, the setup procedure is terrible convoluted and prone to failure, so this product really is a failure.

The electronics alone, excluding plastic parts, the camera and assembly is $43... Digging a bit, I found that it was formerly priced at $199 here in Norway and at that price, they would actually make some money (but not many would buy it). Can the "Automated shopping with Tesco and Amazon Fresh" really pay for the remaing $40 + costs + profits of this device?

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Testing camera modules for use with the ESP32. More details here https://flashgamer.com/blog/comments/esp32-and-the-ov2640-camera-module and here's some microscope shots of the sensors. The actual sensors are too small for my Microscope to see, but I love how the color plays!

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I've always found it hard to get hinges right, but here is a neat trick. Attach the hinge to the door, put double-sided tape where you want to attach the other side of the hinges. Adjust as much as you want and press the hinge to the tape when you think it's right. This allows you to test the hinge for fit and position as many times as needed.

When you're happy with the position, pre-drill the holes, detach hinges and remove the tape. Then you can drill and mount the doors perfectly fitted, flush with the cabinet.

[maketronics]

First floor finished! Very happy with the lighting setup & cable paths. Will end up completely hidden.