Electric cars are very much en vogue right now, as the world tries to clean up on emissions and transition to a more sustainable future. However, these vehicles require huge batteries as it is. For heavier-duty applications like trucks and trains, batteries simply won’t cut the mustard.
Normally, the solution for electrifying railways is to simply string up some wires and call it a day. China is trying an alternative solution, though, in the form of a hydrogen-powered train full of supercapacitors.
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Smart kitchen appliances are expensive, and more often than not, your usage data goes to whichever company operates the inevitable cloud service. Meanwhile the cheap ones contain substantially the same components without the smarts, so surely a hardware hacker can add a microcontroller to a cheap appliance for a bit of smart home technology without the privacy issues? It’s something [Liore] has done with an Amazon Basics kitchen scale, removing the electronics and wiring up an ESP32 to the load cell instead.
The Wheatstone bridge load cell circuit generates a tiny voltage difference that’s far too small for an ESP32 to measure, so in between the pair is an Avia Semiconductor HX711 strain gauge amplifier module. In addition, there’s a small OLED screen and the two buttons used in the Amazon scale are wired in too, providing the the kitchen scale functionality you’d expect.
Naturally the ESP32 brings along with it WiFi networking capabilities, which [Liore] has taken full advantage of here. By navigating a web browser to its IP address, you’ll receive the scale’s current reading in JSON format. This should make it easy to integrate with other systems, from Home Assistant to OctoPrint. We can see that there is plenty of scope for further enhancements for those prepared to write a little code.
Of course, this isn’t the first enhanced scale we’ve brought you, here’s one with Bluetooth. We’ve also seen hackers dispense with the kitchen-safe trappings and build the load cell directly into their own contraptions.
Lithium batteries have, nearly single-handedly, ushered in the era of the electric car, as well as battery energy storage of grid power and plenty of other technological advances not possible with older battery chemistries. There’s just one major downside: these lithium cells can be extremely finicky. If you’re adding one to your own project you’ll have to be extremely careful to treat them exactly how they are designed to be treated using something like this boilerplate battery protection circuit created by [DIY GUY Chris].
The circuit is based around the TP4056 integrated circuit, which handles the charging of a single lithium cell — in this design using supplied power from a USB port. The circuit is able to charge a cell based on the cell’s current charge state, temperature, and a model of the cell. It’s also paired with a DW01A chip which protects the cell from various undesirable conditions such as over-current, overcharge, and over-voltage.
The best thing about this design isn’t the design itself, but that [DIY GUY Chris] built the circuit schematic specifically to be easily copied into PCB designs for other projects, which means that lithium batteries can more easily be integrated directly into his other builds. Be sure to check out our primer on how to deal with lithium batteries before trying one of your own designs, though.
Continue reading “Copy And Paste Lithium Battery Protection” →