Some neat devices for the hobbyist

Ok, well, the year is coming to an end and I’ve seen a number of neat devices out there but here are some that I own. The next year coming up is a going to be an interesting year methinks especially since there’s gonna be some big changes in my life, not to mention the fact that I’ve quit smoking for some time now.

Anyways, here they are:

Arduino NANO

Arduino NANO

This nifty little device is the Arduino NANO. Now, me being me I believe that the arduino’s are something akin to cheating since you don’t need a programmer, it runs right off USB and communicated directly with the computer. The small size of this device and the ease of use make it truly a neat device. Call me lewis ’cause I am starting to like the arduinos. They sell for as little as $14 on EBay (they are probably knockoff but work fine) and are strangely useful for bashing out simple stuff.

Mini PIR Unit

PIR Sensor

This little guy can detect motion (heat difference) up to 5M away. it only draws .15mA and costs only about $4 on Ebay. The interface is simple with two trim pots, one to set the sensitivity and one to set how long the signal stays high when triggered. I bought a whole bunch of these for a project I never finished (A distributed monitoring system) and I might make something cool out of them.

2.4Ghz Transceiver

2.4GHZ transciever

This little guy seems to work really well. Based off the nRF24L01 chip, this transceiver will draw about 15mA at continuous load. If you’re using it intermittently, it’ll run at about 2mA. Alos, it was really hard to get an image of the pinout for this device since the seller kept saying they’d give it to me and never did. Here’s an image of the pinout.

transceiver pinout ripped from somewhere I don't remember (sorry)

You can get these devices for about $4-5 each. A real steal.

CP2102 USB to Serial out

CP2102 USB to IO

These guys are useful because you can plug a test device directly on to the usb port and not need a max232 or equivalent. It features a 3.3 and 5v port and works like a damn. Concievably you could use this with an intermediary to provide the SPI interface to the 2.4GHz Transceiver and use it to provide communication to other transceivers to the computer.

UltraSonic Transducer

Ultrasonic Transducer

This is the ultrasonic transducer. I was playing with it last night and it works really well. It measures anywhere from about 1 inch to 16 feet or so. Simply provide a short 10 to 100 us pulse to ‘trig’ and measure how long the ‘echo’ pin remains high. the ‘echo’ pin will go high after a delay once the trigger pin has been pulsed. I was able to get pretty good accuracy once I calibrated it and with some averaging routines I was abble to get resolutions of about .01″. Surely it wasn’t THAT accurate but it was close. These again were only like $6 each. It should be said, that with full measuring duty this device draws about 15mA.

Anyways, that’s what I’ve been playing with. Hopefully other people may purchase these little trinkets and have fun. EBay sure is an awesome place for the hobbyist like myself for weird knick-knacks!

Pre-Christmas things I’m workin’ on!

Well, it’s been a while since I’ve posted anything (I think every post starts like this) so I’m gonna document a few things I’m working on right now. Things that are both for work and some things that are not.

First off, the Mikro C compiler deal. A few days ago I went over the the mikroelectronika site and noticed that they had a sale on their compilers, a large develpment board for free if you get the compiler. I already have the PIC-C compiler but I figured it’s time to buy a new on since I haven’t actually purchased one for years.

So, for $250 you get both the compiler and the large development board.

Lot's of buttons and lots of stuff.

So there is the BIGPIC 6 board. It’s a well built board, .120″ thick and the parts and overall quality are top-notch. Granted, I haven’t used it much since I’ve only had it a couple of days, but if you’re going to try out a compiler and want a development board to test out your compiler, this may be your ticket.

The BIGPIC 6 in profile

The only thing I was disappointed about was the lack of inclusion of the displays. They’re not that expensive and from the site has them for way too much money. You can buy them off EBay and wire them yourself if you want though.

Ok, and now for another item of interest of things from the work front. Gages! RTJ gages, BX groove gages and RX gages.

I’ve been tasked with designing our new series of RTJ groove gages. My primary idea is to make it completely electronic and build a non-referential gage. Basically my electronics version is a linear bearing attached to a DRO slide

Digital Gage
My Digitial Gage Design. I have most of the parts and am working on the electronics

Doesn’t look impressive, it’s just a prototype really. Here are the actually slide and dro scale. Right now I’m working on interfacing the LS7166 quadrature interface controller but that’s going to take a while since I have to work on the dial indicator version of the gage since the old design has started to reveal problems.

Dial Gage for RTJ Grooves

Anyways, I have all of the materials and I am working on the varieties of things needed to complete these things.

Linear glass encoder
Linear bearing
Yes, an Arduino!

Anyways, these things are all coming along nicely and not in a vaporware kind of way. I shall keep things updated.

Electronics lab on the cheap

Now, for those of you who don’t know me, I’m a total cheapskate. I hate paying good money for good things and wind up buying lots of crap for lots of money. Over the years I’ve seen the question asked by fledgling electronics buffs ,”What should I get to outfit my lab?”

Now this innocuous question is usually asked by people who either don’t have money or are cheapskates like me. I have purchased all kinds of cheap and slightly-less-cheap stuff from a variety of sources over the years and I’ve seen the quality and lack thereof. I’ve worked with it and I’ve had my problems with it. What I figure might be informative is a general guideline of some things I’ve bought over the years, especially the cheap shit, also my opinions on this stuff for people who are starting out.

It should be stated that I’m no expert on electronics and perhaps that makes my opinion suitable for the new hobbyist like myself. Sometimes acceptable is good enough.

The Multimeter

Every hobbyist needs a multimeter. They tell you voltages, resistances, current and often times things like frequency, diode voltage drop,  continuity and various other things. This will be your most important tool when things don’t work as they should or when building a circuit.

Cheap chinese multimeter
The cheap chinese multimeter

Above is the cheap chinese multimeter. They come in various colors and designs and you can pick them up sometimes for $5. While they seem like a good deal, they are not. I have had a great many of these and they have all been a problem in one way or another. Either the voltage shown is wrong, or the fuse inside is pre-blown or sometimes certain functions simply don’t work. If you just want one around your house to check to see if something is live, buy one but otherwise I would stay away. Now for the hobbyist, there is the middle of the road multimeter, these are the ones I would get if you want a blend of quality and cost effectiveness. Some brands to consider are :

  • Agilent ($99 to $150)
  • Extech ($50 to $100)
  • Uni-T ($35-$100) meh..

There are others but those are the ones I have experience with. Obviously the more money you spend, typically the better product you’re going to get. If you’re gonna cheap out on anything in your lab, don’t cheap out on your multimeter, it is the single most important tool in your lab. Remember to get one that’s auto-ranging and don’t bother with ones that aren’t auto ranging or have those transistor testers on them. Transistor testers are the mark of a shitty multimeter.

The Power Supply

Whenever you do electronics work you need some source of power. This can range from using the USB port on your computer (like with an Arduino) to getting fully programmable supplies.

From diy site
From a diy site on a refitted computer power supply

Some people try to save a few bucks and use a computer power supply for their projects. This isn’t bad since it outputs a whole lot of different voltages (3.3v, 5v, 12v, -12v) and can usually supply a whole lot of current. Only problem I have with them is the fact that they don’t tell you much about how much juice you’re using and you can’t limit the current.

Some people are really cheap and use wall-warts (like I did) for power. This is almost universally a bad idea because wall warts can fail spectacularly when shorted out or exposed to weird power loads. If you value your time and parts, don’t experiment this way.

A regulated DC power supply. This is basically the standard model made in china and is marketed under like 30 different brand names.

The best way that’s cheap is simply an analog adjustable power supply. They go for about 110 to 140 bucks and will last you a long time under normal use. You can adjust both maximum voltage AND maximum current so you can perform various tasks with it and save yourself headaches sometimes by limiting current. Trust me on this, for most things this is the best option.

Oscilloscope

Everyone wants to be able to diagnose problems with their circuits, see if there is actually changes going on over data lines, or see if there’s noise on your power supply or something. Also it just looks cool to have a 50’s mad scientist’s lab for when people come over.

This is one item that I see people cheaping out on all the time, and frankly myself as well. While I don’t have top end equipment at the moment, I have second hand equipment that is pretty good.

Your basic analog scope

Above is your general, all purpose analog scope. For most things this guy will serve you well. Buying a new one is often almost as expensive as buying a digital storage scope so buying one like this should be second hand. You can get an analog scope for a song on EBay sometimes and even around town at universities and college, they have extras kicking around. Using an analog scope correctly is a good skill to have and will serve you well with your digital storage scope, if you decide to get one.

a Digital Storage osciloscope

These may be your ticket to have in your lab. Some companies like tequipment sell GW Instek oscilloscopes for $300 or so. While it can be a bit of an investment, this may be your ticket to having decent equipment for your hobbyist lair. The one shown above is obviously an older one and similar to my tektronix 100mhz scope. I got mine second hand for $400 and it’s been a great investment. To be fair, there are other economy brands such as OWON, Rigol and others but I only have experience with the instek ones.

An example of the DSO Nano

The DSO Nano. They are cheap and tempting but they are not worth the money. From what I can tell, they have very low bandwidth and aren’t that great. There is a new model out for about 180 bucks, I may buy one to see what it’s all about. There are other portable DSOs out there but anything that’s any good is a fair amount of money such as the Fluke 123 and various others. OWON makes one for about $500 I believe.

An example of a usb oscilloscope

Well, some people like Dave from EEVBlog warn people away from these USB oscilloscopes but I wonder why sometimes. The only difference really is that the display is now standard hardware instead of the company having to engineer a whole interface on custom hardware. It should be noted though to stay away from the cheap ones on EBay. The ones for about 60 bucks have a bandwidth in the low KHz, yes, not MHz and they suck. Stay away from cheap USB oscilloscopes. somebody who appears to make good ones is Picotech, but that said they are the only company I have experience in that regard.

Anyways, You can get away with $300 oscilloscopes for hobby work, don’t cheap out if you can help it. It’ll make your life easier.

The Rest

Well, I don’t know if I can say “The rest”. there are so many things you can buy to accompany your lab that it’d take many tens of pages of writing to cover even in a very cursory fashion.

I’ll list a few things in point form you could need in your lab to make it both workable  and useful.

  • Breadboards – Cheap and effective, get at least 2. You can get them for 5 bucks each on EBay
  • Soldering iron – Spend 100 dollars and get a temperature controlled one. Weller or Hakko. Those cheap 20 watt soldering irons suck and you’ll waste more time than anything with them.
  • Side nips, you can get these for like 3 dollars.
  • Wire strippers – Again, EBay, Cheap. Get the lower gage ones 20-30 gage unless you do a lot of speaker wire and power stuff.
  • Wire – get some rolls of solid core wire in both 22 and 24 gage. get different colors. red, black, green and white are recommended. more colors the better.
  • Resistors – you can get sets of resistors off EBay or from Jameco for cheap. Get 1/4 watt ones, that’s standard.
  • Diodes – a pack of diodes off ebay might cost you upwards of 2 dollars. yes. cheap
  • component packs – These carry a whole slew of random parts you might need. Everything from switches and caps to potentiometers and other goodies.
  • Alligator Clips – Get some alligator clip wires, very handy for everything.
  • A good light – Get yourself some adequate lighting, only costs a few bucks but makes working much more pleasant.
  • Arduino – Personally, I hate arduinos but if you’re new to things, get one. It introduces things in a much more pleasant way and allows results quicker.

The DON’T List

  • Don’t get random resistors in a bag, waste of time and money. the standard set is fine
  • Don’t get bags of transistors, you’ll never use them. You’ll never really know what they are. You’ll never really know if they’re any good.
  • Don’t get IC grab bags. You will very rarely get anything good. Trust me, I’ve bought them before.
  • Don’t buy Stick Irons for soldering, they suck!

Anyways, that’s what I have to say. I’m sure I’ll get comments telling me how painfully incorrect I am and that I’m a subhuman monster for saying such things. If I’m terribly wrong, tell me, perhaps I’ll change it.

It should be said that I started out with damn near nothing but a bench and a $10 multimeter. I struggled and struggled and bought nothing but cheap crap because I’m a cheapskate. I didn’t buy a compiler and there was no such thing as an Arduino (At least not to my knowledge) so I wrote all my programs in assembly which is extremely time consuming.

Anyways, I suppose what I’m trying to say is that if I can learn it, anyone can. even on a limited budget. If you’re serious about it though, spend the extra few bucks and get something decent.