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Comment by IgorPartola | Hacker News Reader

If you are interested in micro controllers, my recommendation is to get a $20 soldering iron, some lead free solder, flux, breadboard, jumper wires, Wemos D1 mini or Pro, LEDs, resistors, buttons, distance sensors (IR and ultrasonic), temperature and humidity sensors, relays, and some speaker wire. You can get all that from China for about $45. Get 2-3 of the Wemos boards as you’ll likely fry one.

If you are into home automation, look into Sonoff stuff. It uses these chips but comes nicely packaged into several different form factors. You can run open source firmware on them.

Plain Arduino (AVR) boards don’t have a ton of advantage over the ESP8266 and ESP32 chips. So I’d honestly mostly skip them except if you want a ton of GPIO pins or if you want to use the Uno form factor with the shields. Having Wi-Fi is such a huge thing that I think it outweighs the other considerations. Good luck!

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Why the recommendation for lead-free solder? It's harder to work with, the fumes are more poisonous than leaded solder, you shouldn't eat/lick either, and the amount of lead is harmless for DIY solderers. I agree that lead-free solder is environmentally preferable for mass-produced products that eventually end up in a landfill somewhere in Africa, but for a DIY project, I don't see the advantage. I'd love to be proven wrong though :)

> the fumes are more poisonous than leaded solder

What do you mean?

> the amount of lead is harmless for DIY solderers.

To date, the FDA, CDC, and the WHO state that "no amount of lead is harmless". It's just that we can't get a sensitive enough handle on the neurological effects to determine a good metric for it.

On another note, does anyone know if the Respro masks are suitable for protection against lead (+ the stuff with lead) inhalation while soldering? The "techno" mask has a HEP-A filter and a charcoal mesh, which I would have thought would be enough for most of the lead particulate?

As far as personal harm during the actual soldering, it's not hard to use lead solder safely.

You have to breath it or ingest it for it be dangerous. In soldering it does not get anywhere near hot enough to vaporize, so really all you have to worry about is ingestion.

As long as you either don't touch the solder, or are careful after touching it to not touch anything that may find its way into you until you can thoroughly wash whatever parts of you touched the lead (or were touched by parts of you that touched the lead), you should be OK.

The biggest health risk during soldering is going to come from the flux. It's the flux burning that produces the smoke you see and smell during soldering.

Here's a document from LBNL on safe soldering practices that goes into the components of solder (leaded and lead-free) and their dangers: http://www2.lbl.gov/ehs/ih/pdf/safeSolderingFinal.pdf

My understanding is that there are no lead fumes. It becomes a gas at like 3200 degrees. Your soldering iron won’t make it into a gas and if you are inhaling fumes that hot you have bigger problems. My main issue with it is that I don’t want any residue on my work surfaces where my kids might play with it, or on any electronics they might touch.

It's lead, not ebola.

Although that degree of caution is more or less warranted when dealing with lead solder in paste form, I have to admit. That crap gets everywhere.

> It's lead, not ebola.

Exactly.

Fumbling around with a soldering iron and some leaded solder a little bit, few times a decade, won't give you cancer or any poisoning. Safety considerations are aimed at people doing lots of soldering, because at this point the amount of flux fumes they might breathe in (or risk of ingesting lead) becomes a possible risk.

(And to be honest, I believe most of this safety advice is aimed not at DIY people, and not even at people who occasionally have to solder something at work, but to have a stick that will prevent employers in soldering shops from creating very unhealthy conditions for their workers.)

The ESP chips are not trivial to hook up, unless you get something like a NodeMCU. The original breakouts are not breadboard friendly, and they have (comparatively) weird requirements for programming (e.g. some pins need to be pulled up, which means you need to breakout the breakout boards). They're also not 5V tolerant, which means you normally need a regulator and have to worry about interfacing. The documentation is OK, but it's a warren of official documentation, Wikis, Github and forum posts.

I would say that the Arduino advantage is that it's truly out of the box. ESP8266 is close, but it's not that easy.

If you want an easy IoT dev board, I will always recommend the Particle Photon (no affiliation). It's $20 and has really great documentation. It will do OTA updates out of the box once you've set it up on your network using a smartphone. It's a separate IDE (cloud based, or you can get an offline one), but you still use Wiring and they've retained the setup() / loop() constructs. I have had some issues with devices not connecting to networks using the chip antenna, so you probably need the external one.

Other minor issues - most ESP boards are not FCC/CE compliant. They're just fake stamps on the EM shield. Some of the boards are, but you need to be careful if you're trying to build a product or worry about interference. The Photon, on the other hand, is certified (and they also certified it with a suitable external antenna).

The nice thing about working on 3V is that they're stupidly easy to power using 2AA batteries, but I agree it's a bummer they're not 5V tolerant otherwise it would be as easy to power over USB.

They are 5V tolerent on the logic pins, just not on the power. LiFePO4 batteries work great for powering them as their voltage curve matches perfectly without regulation.

My understanding is that this is mostly a dangerous myth. Like it sort of works but you really shouldn’t unless you are ok frying the board. I have been sticking with mostly 3V components and have a separate set of rails and transistors to control that side of things.

No, that's wrong. The signal pins absolutely are 5V tolerant (confirmed by the CEO of Espressif) and work perfectly but if you put 5V to VCC it will fry instantly. I know from experience, in both cases.

It used to be the case that people were unsure if the logic pins were 5V tolerant or not due to ambiguity in the datasheet and the consensus was to be cautious, but it has since been officially confirmed that they are tolerant. Some other devices (e.g. relays, some MOSFET gates) might require a 5V output level to trigger, in which case you will need a level shifter/transistor, but 5V inputs to the pins are fine (and most digital devices that work at 5V logic levels will be fine with 3.3V logical high due to the way TTL levels are defined).

Thanks for the info. I stand corrected.

According to the CEO of Espressif, Teo Swee Ann, the I/O pins of the ESP8266 are 5V tolerant.

See discussion here: https://hackaday.com/2016/07/28/ask-hackaday-is-the-esp8266-... and official reply on Facebook (of all places): https://www.facebook.com/groups/1499045113679103/permalink/1...

> Teo Swee Ann i can reply officially here: it is 5V tolerant at the IO. while the supply voltage is at 3.3V.

And, the built in A/D will give you the current voltage reading with no additional wiring so you can post it to your MQTT instance and monitor when you need to change/charge your LiPO :-)

Wemos chips are breadboard friendly and while they require hat you solder the pins, that is pretty trivial and something you will need to learn anyways.

Yes there are loads of other breakout boards that suck but I found Wemos ones to be great.

There's a ton of decent boards:

Adafruit Huzzah https://www.adafruit.com/product/2471

NodeMCU is good, there's a ton on ebay.

+1 on the Wemos D1 mini recommendation. I have 5 or 6 and are great little boards. If you need some more pins the, you can get the NodeMCU boards.

can you share some links to where to buy? where to learn some basics? thanks!

AliExpress.com has it. Just search on there. Note that for Wemos specifically there are a ton of clones that don’t actually say “Wemos” on them. Get the branded ones as the price difference is negligible.

https://www.aliexpress.com/store/group/WeMos/1331105_2571030...

https://m.aliexpress.com/s/item/32765214054.html?spm=a2g0n.s...

https://m.aliexpress.com/s/item/32454217006.html?spm=a2g0n.s...

The soldering iron is the only thing I got state-side. I went with one that has temperature control so I can do lead-free solder.

Tayda and SmallBear market to the hobbyist maker. They stock common ICs and components, and don't mind small / single unit orders.

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