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The Amazing $1 Microcontroller (2017)

jaycarlson.net

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Re: The Amazing $1 Microcontroller (2017)

#91

Post by lstodd »

generallee5686 wrote: post #88
lstodd wrote: post #85

Earlier quoted context omitted.

It doesn't measure voltage and thus can't measure true energy consumption = power, only currents. It then must estimate power based on some preset voltage. Not to mention those clamps can't have precision or time resolution for truly interesting stuff. A toy, in other words. It might be good enough to get a rough idea what eats more or less and when, but it'll never match the utility power meter which is what you're…

The IoTaWatt does measure voltage. You plug in a calibrated AC wall wort as well as the DC USB power supply.

Well, sorry, then. Missed that bit on their site.

Still, inductive current measurement with the sizes of the clamps they show and typical currents they're measuring isn't accurate at all. Not even considering that voltage measuremens via a wall wart would depend on what load is currently sharing the same wiring.

This might be my bias since I design similar stuff for solar offgrid, where a percent or ten off are that much in capex divided by battery lifetime, then multiplied by battery cost. It bites.

I don't trust inductive clamps at low currents. I would never trust measuring voltage on the same line as a load.

Hall sensors or current shunts; voltage dividers - all driving MCU ADC channels via optoisolated opamps. Everything measured as near to the source as possible. Otherwise you're getting nearly worthless data.

Re: The Amazing $1 Microcontroller (2017)

#93

Post by sand500 »

spacedog11 wrote: post #86

The title is misleading because only the chip by itself costs $1. If you buy the microcontroller( chip + peripherals), it costs more than $1. For example MSP430: https://www.mouser.com/ProductDetail/Texas-Instruments/MSP-E...

Yeah, I probably wouldn't be concerned about the cost of the actual chip but rather the cost of w/e dev board I would need for my hobbyist project. Maybe the complexity of wiring everything up if I were to put the microcontroller on a custom designed PCB.

Re: The Amazing $1 Microcontroller (2017)

#94

Post by patrickyeon »

spacedog11 wrote: post #86

The title is misleading because only the chip by itself costs $1. If you buy the microcontroller( chip + peripherals), it costs more than $1. For example MSP430: https://www.mouser.com/ProductDetail/Texas-Instruments/MSP-E...

"Microcontroller" refers to everything on the chip (usually, we would talk about it having a "core" roughly akin to memory + ALU + such, and "peripherals" which are on-chip dedicated hardware that migh be eg. I2C or USB communications, timers, ADCs, etc). What you're linking to we would call a "development board" (dev board), "demo board", "eval(uation) kit".

I don't consider the title misleading, as the article is aimed at the people who are designing their own (hobbyist probably, but not exclusively) boards, and will be integrating the chip, not a dev board, into their project.

Re: The Amazing $1 Microcontroller (2017)

#95

Post by watermelon0 »

foobarian wrote: post #80
magicalhippo wrote: post #64

Earlier quoted context omitted.

> You also need to include fuses and other safety circuitry to ensure it doesn't exceed that threshold your microcontroller can accept. I'd say you need to include other safety circuitry, as well as proper PCB design, to make sure it doesn't start a fire. If you don't know what you're doing, don't rely on random stuff from AliExpress etc to be grid safe, and don't try to make stuff that connects to the grid yourself.…

I would be terrified of any kind of relay there. I had a few relays fail on my furnace such that they burned a 1" diameter hole in the PCB.

If you have a device drawing high current, you would probably use a contactor (high-power relay), and then you can use low current (or even low voltage) relay/triac to drive the contactor from your circuit.

Re: The Amazing $1 Microcontroller (2017)

#97

Post by lstodd »

merpnderp wrote: post #63
neya wrote: post #8

My favorite is the ATTINY 85. It's so cheap and yet, it can do almost most of the things you can do an Arduino. And yes, you can program it using the Arduino IDE as well. Last year, I started out to digitalize my entire house with these tiny ATTINY 85 chips and with some nrF wireless chips. It has worked really well for me and I'm able to control and monitor any power port in my house as well as my mains. The overall…

How are you switching mains power safely? I looked into it, but gave up when I realized I'd have to install a rectifier in the wall which just seemed like a fire waiting to happen.

There are basically two options:

- learn how to and design a PCB with relays or FETs or whatever, following all the best practices for it to not catch fire.

- buy off-the-shelf rail-mounted relays/contactors, then design a driving circuit that will be all low voltage.

Assembling it all on a breadboard won't cut it (as in will blow up sooner or later), that's for sure.

Re: The Amazing $1 Microcontroller (2017)

#98

Post by aaroninsf »

foobarian wrote: post #80
magicalhippo wrote: post #64

Earlier quoted context omitted.

> You also need to include fuses and other safety circuitry to ensure it doesn't exceed that threshold your microcontroller can accept. I'd say you need to include other safety circuitry, as well as proper PCB design, to make sure it doesn't start a fire. If you don't know what you're doing, don't rely on random stuff from AliExpress etc to be grid safe, and don't try to make stuff that connects to the grid yourself.…

I would be terrified of any kind of relay there. I had a few relays fail on my furnace such that they burned a 1" diameter hole in the PCB.

watermelon0 has the correct answer: [most] hobbyists should stick 100% to low-voltage low-current applications and use off the shelf certified hardware whene interfacing with high-voltage (i.e. mains) power.

MEE hobbyists, disregard.

Re: The Amazing $1 Microcontroller (2017)

#99

Post by blhack »

gmiller123456 wrote: post #76
blhack wrote: post #47

I feel obligated to mention in every one of these threads the wemos D1. I actually have a tough time explaining just how incredible this board is. You can program it in the Arduino environment, meaning if you are doing any hobby electronics, you're probably already really familiar with the programming modalities. It comes with a programmer, and power regulator. No fussing with anything like you might have to with a b…

I actually prefer the Wemos D1 Mini. The D1 you linked has the same header layout as the Arduino, which might confuse a lot of people that you can use Arduino shields. Some of them might work, but probably not without modifying the libraries for them. The D1 Mini actually has it's own shield format, and several shields are available. Even experienced people will find value in the ability to just plug in a display, or…

The uno format is exactly why I like it. It means I can use screw shields made for the UNO on it. Also lots of other shields that will accept 3.3v logic.

Re: The Amazing $1 Microcontroller (2017)

#100

Post by Gibbon1 »

cr0sh wrote: post #69
neya wrote: post #8

My favorite is the ATTINY 85. It's so cheap and yet, it can do almost most of the things you can do an Arduino. And yes, you can program it using the Arduino IDE as well. Last year, I started out to digitalize my entire house with these tiny ATTINY 85 chips and with some nrF wireless chips. It has worked really well for me and I'm able to control and monitor any power port in my house as well as my mains. The overall…

Are you in the United States? I'm just curious how your homeowner's insurance feels about this? That is, will they still pay out for a claim should something happen, and they determine your modifications were at fault? Because if the adjuster or whomever does find you have such modifications - they -will- blame those. And probably deny your claim and coverage (and probably cancel your policy). At least that would lik…

In the US the home owners policy like auto insurance isn't to protect the home owner. It's to protect the bank holding the mortgage.

The flip side of that is the risk of a geek installing a power monitor without permits pales in comparison to someone plugging a 1500 Watt wall heater an an ancient wall outlet.

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