Reddit mentions: The best transistors

If you have only a very small number of motorized blinds (I'd say four or less), then Hunter Douglas provides good options to wire them up. You can either install battery packs that need to be serviced every few months, or you can plug in a small power supply. Each of the power supplies can drive up to two blinds. But the extension wires that come with it cannot be longer than about 15ft, and they are not rated for in-wall installation. So, you'll have to deal with them probably being visible.

If you have lots of blinds, the wires look ugly, and you really don't want to take up a gazillion outlets. We have dual stacked blinds (mesh & black-out) in a few places. There clearly aren't enough power outlets to handle that.

Hunter Douglas for better or for worse runs their blinds on 18V -- and their tech support claims that the blinds are pretty sensitive to voltage fluctuations. This has a couple of awkward consequences. 18V power supplies are really unusual. Laptop power supplies would be perfect, but they are all 19V, which according to Hunter Douglas is not acceptable. And other common voltages are 12V or 15V, which are both noticeably too little.

Furthermore, the blinds have relatively high peak currents. Hunter Douglas told me to roughly assume that each blind can require up to about 10W. Took me forever to find a place that sells an 18V/180W power supply, as Hunter Douglas doesn't offer any solution themselves.

Of course, that's the raw circuit board only. You still need an enclosure. I went with a 12V enclosure and modded it. The enclosure is a great size, and you can even reuse the metal shield for the power supply, if you are careful. It also conveniently already comes with all the fuses that you'll need anyway. So, that saves you quite some work. But you do need some tinkering experience to swap out the circuit boards. You probably also need to order a couple of Molex connectors and you'll need to do some crimping and some soldering.

The next problem that you'll run into is that the enclosure needs a cooling fan, but as far as I can tell it is impossible to find 18V fans. I ended up using an ATTiny85 and a MOSFET to PWM the 18V so that I could safely drive the existing fan (make sure to configure the micro-controller for FastPWM, or you'll have to deal with an ugly humming noise!). And while at it, I also added a temperature sensor, so the fan only turns on, when needed. You also need a small DC-DC converter to power the microcontroller. And if you don't already have a way to program Atmel chips, you'll need to buy a programmer. EBay has lots of cheap options, too. All of this definitely takes some amount of tinkering skills that not everybody will have, though.

Overall, building a proper power supply and distribution box cost me just over $200 in parts. Not too bad. But the amount of time spent getting it to work was ridiculous. Especially if you add up all the time researching which parts I needed to buy in the first place. I really don't understand why Hunter Douglas couldn't sell ready-made power supplies for installing multiple PowerView blinds. Even if they charged $500 for the ready-made box, that wouldn't be entirely unreasonable -- and that would be a huge mark up and make them quite some profits. In bulk, each supply should cost less than $100 to manufacture.

The next problem is finding appropriate cables. At those low voltages, currents are going to be high, and if you have anything more than trivially short runs, you'll encounter significant voltage drops. Since Hunter Douglas said that sticking as close as possible to 18V is crucial, you'll inevitably have to install beefier wires. Hunter Douglas recommends 14AWG for powering up to two blinds, or 16AWG when powering a single blind. I had good luck with buying Monoprice in-wall speaker cable for this purpose. Get the four-conductor version to minimize the number of cables that you need to string.

Ideally, you want to avoid splicing the cables. And in many cases, if you plan carefully, you'll be able to do that just fine. But sometimes, splices are simply unavoidable (for instance, when joining 16AWG cables to an 14AWG cable). I find WAGO connectors work really well for this purpose; unlike wirenuts, they can be used both with and without ferrules. And they work well for stranded wires, where wirenuts sometimes fail.

The blinds have barrel connectors, and Hunter Douglas suggests buying plugs with screw connectors. That is a good suggestion in principle, but I find it is impossible to securely fasten the speaker cables in the screw connectors, unless you use ferrules. And that means, you'll also need to buy a crimping tool. And for good measure, you should probably shrink wrap the entire contraption afterwards. High currents means you want secure connections.

Ideally, you should run all the cables inside the walls. But that's not always possible. If you can't, then you'll need to staple them instead. Make sure to use the right staples. I asked my electrician to help in order to meet my schedule; in hindsight, that didn't work out so well. He sent me his apprentice, who promptly proceeded to run each and every staple straight through the cable. Ouch. We had to redo all the wiring.

Now, my next project is thinking of a solution to hide the Hunter Douglas remote inside of a Decora wall switch. The remote is OK, but it looks a little cheesy when wall-mounted. As I said before, PowerView blinds are fine in principle and they are probably better than most competing products, but they do feel a little unfinished at this time. When they do work though, they are really convenient.

Honestly you can get a bunch of the individual stuff separately on amazon. Here are some recommendations I have:

Get a volt meter that can measure ohms and current (mA):

https://www.amazon.com/gp/product/B00KHP6EIK/


Red/Green/Blue LEDs:

https://www.amazon.com/gp/product/B0059H5Z5O/

https://www.amazon.com/gp/product/B004UMA60S/

https://www.amazon.com/gp/product/B0059H5Z5O/


Breadboards:

https://www.amazon.com/gp/product/B01258UZMC/


Jumper wires:

https://www.amazon.com/gp/product/B00ZWEFWO8/


pir (motion) sensors:

https://www.amazon.com/gp/product/B017HP88VI/


transistors:

https://www.amazon.com/gp/product/B00R1M3DA4


resistors:

https://www.amazon.com/gp/product/B0185FGTSS/

https://www.amazon.com/gp/product/B0185FGN98/


The multimeter is great, you can make sure you wont fry your GPIO outputs. Try not to pull over 16mA of current per pin to avoid damage. Use a 1k or 330 ohm resister accordingly. You can also do a lot of cool stuff with a transistors and LEDs.


I've been documenting a lot of the electronics stuff I've been teaching myself; About six months ago I was where you were, setting out trying to learn how to use all these components. Feel free to reach out if you have any questions. I'd recommend going to the oldest post on my blog and reading in order if you want some ideas: https://supertechnologyknowledgequest.blogspot.com

PM me with any questions, I'd be happy to point you in the right direction for anything you are trying to do for which I can help! Best of luck!

edit: the multimeter is no longer on amazon, just find one that lets you read resistance AND current (milliamps).

I picked up an awesome cheap tool I forgot to mention and it was only $15:

https://www.amazon.com/gp/product/B071Y5CHPK/ref=ppx_yo_dt_b_asin_title_o00__o00_s00?ie=UTF8&psc=1

You have to assemble it and it doesn't come with instructions, but it's so good. I use it to test parts before soldering them in, that way I know I have properly working parts before putting them on the board so if I have any problems later, I know it's not the parts. It measures resistors, diodes, caps, transistors, etc. It does the same thing as the $60 atlas DCA and more. The atlas DCA only measure semiconductors, this cheap thing measures passive parts too like resistors/caps, etc. The numbers are slightly different than what my atlas measures, like right now I'm measuring a silicon transistor that is reading 290 hfe on my atlas but 250 on this cheap thing, but it's at least in the right ballpark. The atlas goes into way more detail like leakage and stuff, but the cheap thing at least gives you the hfe and the pinout so you don't accidentally connect the wrong lead to the wrong input. I got a cheap DMM from amazon too that will give you an accurate enough reading for like $15. So for $30, you can have two great measuring tools.

Awesome, thank you. I called it a relay but I meant a transistor. It was this one in fact. Do you think this is okay for the two fans? Should I do one for each to be on the safe side? Or should I buy something different?

Also, do you know of any videos I could watch or books I could read that would help me understand the electricity side of things?

Two years at 30 times a day is 21900 cycles, pretty good for running DC on the chinesium relays that are on that board. You'll get a few more years out of a good relay if you're only doing 1A, but they're still going to wear out on the order of a few years.


You might get better longevity out of an SSR board or something like this: https://www.amazon.com/Diymore-Channels-MOSFET-Button-Arduino/dp/B01MRQFYJN/

Yeah, absolutely. Those aren't even that tiny for a three pin surface mount package, and can be hand soldered with a fine-tip iron. Do you know what the surface markings were before you clipped 'em? I can't clearly tell what type of component it is from the photo, but I did find some other pictures of a KC60 that I'm trying to use to identify the component and values so you can get a replacement.

Edit: It looks like you clipped an A09T transistor. It shouldn't be too hard to find a replacement.

Edit2: Found 'em on Amazon. AO3400 is the same transistor as A09T (in fact, they're labeled A09T).

Whoa...looks cool, but I am not, unfortunately, at all familiar with arduino. It sounds like something I could do, and the form factor is appealing, but what's required?

Looks like one of these and a little ATtiny?

You can just buy one of those cheap LCR/component tester jobbies. They're not as good as a real inductance meter but for basic identification they're fine, great for lots of other quick measurements too.


https://www.amazon.com/Multifunction-transistor-Capacitor-Inductance-screwdriver/dp/B071Y5CHPK

I have done something very similar to this, as I have worked on projects where I needed to control common-anode RGB LED strips. You should just need a common NPN Transistor. Here is a link to some I found on amazon that I find tend to work well, and the bulk pack is pretty nce, And Here is the datasheet for those specific transistors.

If all you want to do is be able to turn the LED on and off, the circuit should be fairly simple. Connect VCC (12v) through a current-limiting resistor to the anode (+) of the LED. Then connect the cathode (-) of the LED to the collector of the transistor, (can be seen in the diagram/datasheet) then connect the emitter of the transistor the ground (- of the power source). And connect the output pin from the Arduino through a small-value resistor to the base of the transistor. With that, you should be able to use the Arduino output to control the higher-voltage LED with digitalWrite(pin,HIGH) turning it on, and digitalWrite(pin,LOW) turning it off.

Here is an example of what that would look like. Ignoring however you plan on powering the Arduino itself, you can see how the LED, transistor and output pins are connected.

 

NPN Transistors normally have 2 "modes" per se. They have an analog mode which uses a change in normally very low voltage to change how much "on" they are, meaning they let different amounts of current flow from the collector to the emitter (In this case the voltage path of the LED) depending on how much current is flowing from the base to the emitter (Arduino to ground, as when the output goes high, it allows current to flow through the transistor's base to the emitter). However in this case, the transistor is mostly going to be functioning in the saturation region, meaning that the Arduino is likely going to be putting out enough current that the transistor will either be completely ON or completely OFF, and you wont get much analog function out of it. However if you want to be able to dim your LED, you can use PWM to very quickly turn it on and off, which can give it the effect of dimming it.

 

TLDR: Use a transistor. Likely NPN would work well.

Edit: In the circuit schematic tool I used, they had the ATMega, but not an Arduino itself. Treat the mega shown as if it were an Arduino, Ex. Has voltage regulators, input pull-ups, etc. The VCC is the arduino's RAW or Vin

I got it from amazon.

Playing around with it, I'm impressed that it can even identify and measure things like coils, capacitors, resistors, etc.

Do you mean something like this paired with this and this and I can use that like a my Arduino Micro? (I guess the Micro has a lot more power though).
How would you connect that to your pc? I thought a programmer was only needed so you can burn your programs to the microcontroller? Could you use that microcontroller without a programmer after programming to it what you want?

> IRL520

Got you. For some reason, I thought the Mega could output up to 12v. So I will get an IRL520 and run it off the board like seen in a few youtube videos. Then get an adjustable sound sensor to control it from the same board. Use two separate power supplies 5v/Arduino; 12v/fan with connecting grounds to the ground in the outlet. Thanks very much all!

It will work just fine, but it's expensive. For future reference, a 2N2222 is a good general purpose NPN that is readily available for cheap.

Like others said, you need to insulate the tabs. Here’s a transistor insulator kit I bought, seems to work fine.

https://www.amazon.com/dp/B017AS9DM0

Bingo. Transistors are switches controlled by power.

Not sure EXACTLY what kind of transistor you'll need, but you should be able to find one easily at RadioShack, Frys, or the internets: https://www.amazon.com/S8050-Silicon-Transistor-Voltage-Current/dp/B015E4DJ90

I just ordered the parts I need. [Found a good deal too](
https://www.amazon.com/pcs-2N3904-2N3906-TRANSISTOR-200mA/dp/B00KHMRG5S/ref=sr_1_cc_1?s=aps&ie=UTF8&qid=1480682405&sr=1-1-catcorr&keywords=50+pcs+of+2N3904+%26+50+pcs+of+2N3906+TRANSISTOR+40V+200mA)

Seems like a great idea, reminded me of this tool I bought. This thing isd badass. I pop a transistor in and it tells me what pins are bce, as well as beta values and misc info. Also test all other basic components, esr to test capacitors in circuit, it also has a built in pwm, signal generators, etc. this thing is a must have, I'm posting it to so you can take a look and give you more iudeas for your project. But look at the pricing and how much people will pay. this thing is $25 and basically tests everything but ic's. An ic tester would be badass. Maybe even have a usb where the home user could update it to test new ic's you add to the firmware? Is firmware the right word. I haven't messed with anm ardrino yet and I have a couple in my lab. Working 6 days a week and don't have the time :( I really wanted to leanr how to use the damn thing.
http://www.amazon.com/Yosoo-Display-Transistor-Cymometer-Generator/dp/B00OOQC2E8?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_detailpage_o02_s00

Even the same manufacturer can differ on the TO-92 because they can be ordered in any pinout you want, but I think the standard EBC applies generally.

OP, for $15 you can check - worth every penny.

Yeah. You can do it all analog if you can get it down to 26 outputs.

Then you just need transistors for the duplicates. Easy peasy.

Edit: You'll have your work cut out for you if you just set out to Google-learn about transistors and relays. This project would be quick with a bank of four of these, but it would also be unnecessarily bulky and expensive. You can do everything those do with just transistors since you're only powering LEDs.

Since you'll have a 12V supply already, you can use that to switch the relays by hooking up some MOSFETs to your NodeMCU. The 12V power and NodeMCU will need to share a ground.

Here's an example of the wiring: http://bildr.org/2012/03/rfp30n06le-arduino/ You would be replacing the motor with your relay

I got a 100 pack of 2N2222 NPN transistors from Amazon for $4.60. Here's the link.

You are correct. These are logic level MOSFETs. They are Bridgold IRLB8721 N-Channel MOSFETs: https://www.amazon.com/dp/B07LG5BCDY

Sample relay or mosfet

Heatsinks $11
Sonoff switch $14.00
N-Channel MOSFET $8.88
Stickable Breadboard $9.99
LED lights $11.25
Google AIY Voice Kit $12
HDMI $6.99
5V Power Supply $7.99
12V Power Supply $9.99
Raspberry Pi $38
Monitor $69.99
Mirror $129.99

Total : ~$330

Apologies,

mosfets

Here’s a listing of all the included material

eBoot 30 Pieces Photoresistor Photo Light Sensitive Resistor Light Dependent Resistor 5 mm GM5539 5539 https://www.amazon.com/dp/B01N7V536K/ref=cm_sw_r_cp_api_i_-wV6CbC6051BJ

Beadalon Artistic Wire 30-Gauge Bare Copper Wire, 30-Yards https://www.amazon.com/dp/B0048927RI/ref=cm_sw_r_cp_api_i_vEV6CbC9KF2ZQ


MCIGICM 200pcs 2n3904 npn Transistor, 2n3904 Bipolar (BJT) Transistors NPN 40V 200mA 300MHz 625mW TO-92-3 https://www.amazon.com/dp/B06XRBLKDR/ref=cm_sw_r_cp_api_i_UEV6Cb66Z0SC2


3mm Diffused LED Diode Assortment Kit - Pack of Assorted Color LEDs and Resistors (1000 pcs) - Red, Green, Yellow, Blue and White Light Emiting Diode Indicator Lights from Plusivo https://www.amazon.com/dp/B07GBFJ823/ref=cm_sw_r_cp_api_i_dFV6CbWBSS5AD

You'd need to disconnect the antenna, yes... but I'd take a guess that the meter you posted won't read capacitance that low anyways. I've had very good luck with this meter when measuring small capacitances, including variables: https://www.amazon.com/Multifunction-transistor-Capacitor-Inductance-screwdriver/dp/B071Y5CHPK it seems to measure down to about 25pf.

The other thing is you might be measuring at the wrong points on the cap. Pay close attention to the mechanism and how it's connected. Put the meter on continuity, and put the leads to the points where you were testing. If you have DC continuity, you're using the wrong points.