The Olimex PIC32-Pnguino with it's large DIP form factor

Specs:

• Manufactured by Olimex
• Price ~$25 USD
• Pic32MX440F256H 32 bit Microchip MCU
• 256K of Flash, 32K of RAM
• Built in microSD slot
• Operating at 80 Mhz
• USB On-the-go
• Geared for Pinguino IDE

First Thoughts:

I haven’t used this product very extensively yet so some shortcomings are awesome points may be missed. I have played with it for a couple of days though and read through most of the libraries and documentation. This product is from Olimex in Bulgaria and to be honest, I’m a bit of a fan of Olimex. Olimex has built some interesting devices such as the DuinoMite and you can really tell that these guys really like what they do. They spend the time and effort to make the boards as good as possible.

Anyways, some thoughts about this board. It’s a pretty neat little board for both prototyping and perhaps even fitting it in to a product. It has a small form factor and would happily fit into a larger board for use in a larger product. The built in microSD port and the USB otg interface allows for some neat things to be made. The pinguino IDE isn’t too bad either. The libraries are reasonably complete and the device works quite reliably with the software as I encountered no bugs or glitches and programs worked as expected.

Pros:

• Small form factor
• .1 dip pinout which is good for breadboarding
• Good price for a 32 bit device like this
• Well built
• UEXT port for other Olimex peripherals is a nice choice
• Fast!

Cons:

• Uses small ICSP port which you must buy from Olimex. I know it’s done for size and not simply to sell a cable but it’s still a bit of a drag.
• DIP width is too wide to fit on a single breadboard, you’ll need to use two breadboards and straddle it over them.
• UEXT connector is taller than everything else on the board. Not a huge issue but most people won’t use the UEXT connector and the header could interfere inside an enclosure.
• like with most 32 bit processors, the pins are not 5V. some of the pins may be 5V tolerant but this simply comes with the territory.

Final Thoughts:

I like the stuff that Olimex builds. They give a shit about what they make and it shows. This type of device is pretty good for almost anyone with a reasonable amount of skill wishing to prototype anything you would normally do with an Arduino. For the price, you can’t beat these guys. In order to get ahold of one you can go through Mouser or look at the Ebay distributor (olimexery). Olimex themselves seems to sell it but they don’t seem to have a slick store setup to do purchasing.

The Wiring S board from Rogue robotics

Specs:

• Manufactured by Rogue Robotics
• Price ~$27 USD
• Uses an Atmega644p (surface mount)
• 64Kb of Flash (double arduino uno)
• 4Kb if SRAM (double the uno)
• overall size (2″ x 3″ x .5″)
• 16 Mhz
• 7-12v input or USB
• 2 hardware uarts
• 1 hardware spi
• FTDI USB to serial interface

First thoughts:

I started off trying a few common things such as accelerometers, switches, sd cards and various other things. Most of the basic stuff from a standard Arduino will work except the SD card will you to program it through the SPI library. The form factor has changed a bit from Arduino in that they have used standard 100mil spacing. Also, they have separated the headers in to groups of 8, you can access each of these as ports instead of straight pins. you could do this with the Arduino but the pins were not always contiguous. Also, using the 644 is great because you get two hardware UARTs. very nice! Other than the changes mentioned, it is pretty much the same as an arduino and the software looks and functions almost exactly the same as the standard Arduino IDE. It all has very good fit and finish and is reasonably priced and functional.

Pros:

• Better pin locations, based on a grid of 100 mill unlike and Arduino which has one row of headers off by 50 mil.
• Better pinout usage. Ports are aligned along the header and power,rst and aref are on their own separate header, much better.
• Easier to reach reset button if a shield were on the board.
• more flash and SRAM than standard UNO, double to be exact.
• inch based form factor (exactly 2×3 inches)
• provision for pins or terminal for direct power feed rather than barrel or usb
• reasonable cost, not super cheap or expensive, comparable
• Switchover jumper for usb power and external
• Canadian Made!

Cons:

• Used huge USB connector like Arduinos. Most others stay away from these since they’re huge and most people don’t like the large cords.
• For the same reason that the header placing is good also makes it bad if you like to use shields for the Arduino
• sd library isn’t implemented but that’s not a big deal
• slightly larger for factor (as per area) than the Arduino but not by much.

In closing:

This product is great for anybody who uses the Arduino or is learning. It’s better in almost every waythan an UNO and is offered for a  reasonable price.

Pop by robotshop or roguerobotics if you’d like to pick one up

Digi-Gage

My Digi-Gage is coming along quite nicely. I spun a set of boards from Itead studio a couple of weeks ago, paid a bit extra for the ENIG and the black soldermask. very nice indeed.

This board is for my digital gage. The board interfaces a PIC18F4685 to a LS7166 and thus counts ticks from a run of the mill glass scale. Hopefully it’ll work as well as I hope.

This is it semi-populated. turns out I forgot to buy the TQFP package MCU hence why the mcu isn’t present on the board. I’ll get the rest of the parts from Digikey soon.

Arduino – devboard collection

Well, I’ve been spending money on all kinds of things and perhaps it’s time to slow down a bit. Especially considering that I don’t use them. Here’s what I’ve got and some thoughts about them.

• Arduino Uno – The standard arduino, handy, very handy
• Arduino Mega 2560 – A bigger version of the standard. Good for extra pinouts.
• Arduino Nano – Extremely handy, combining both the arduino usefulness with a breadboardable stick.
• Chipkit Uno – A (much) faster 32 bit arduino. Only disadvantage is the 3.3 volt limit on IO. That said, it has double the IO of a standard arduino and uses the Arduino IDE
• Chipkit Max – A larger version of the previous one with many more IO.
• AVR Butterfly – Haven’t really played with it yet but it seems pretty promising for something cute and interesting.
• Netduino Plus – Like an arduino but faster and able to be programmed in visual c#. I haven’t figured out how to program it in VB yet, perhaps it’s not even possible.
• Netduino Mini – like the above but with a smaller form. Neat little device.
• Duinomite Mini – another cool device with VGA out just like the Duinomite standard.
• Beaglebone – Still haven’t used this much yet
• Olimexino 328 – An arduino but built well. Great for industrial use. Gotta love olimex.

I decided to record data in my car overnight and through the daytime. From 12:00am to 7:00pm thereabouts. I recorded the data every 4 seconds with the following sensors

• NTC Thermistor
• Low Sensitivity CDS (Resistor that changes when light hits it)
• High Sensitivity CDS
• Accelerometer X,Y,Z axis

Why did I do this? just cause. here is the resulting chart

Recorded data for Feb 1, 2012 in my car

Here is the legend: B = Temperature , C = Low Sens. Light, D = High Sens. Light, E = X axis accel, F = Y axis accel, G = Z axis accel.

All of these values are as the MCU read them, ranging from 0-1023. They are also logarithmic so as they approach 1024, the value is ‘squished’ so large changes appear small.  anyways, I thought it was neat to see the following things occur.

• Temperature of the device goes down as the night wears on. There are some lights detected, probably people passing by in the alley behind my car. some drift is noticeable from the accelerometers (due to temperature change?). Also something to notice is that  X and Y are pretty much the same
• The light appears to go haywire, this is me driving in the dark and going under streetlights. Also, the temperature increases, the accelerometers shake and show the duration of my drive to work.
• As my car is parked you can see that I have parked crooked by the X and Y axis. Also, the sun starts to come up. As far as I could tell, it was pitch dark outside, the sensitive light meter says differently.
• During the day, the overcast sky keeps the sky about the same light level, whereas with the less sensitive instrument, since it’s further from saturation, shows variations in the ambient light level through the day. Temperature also fluctuates.
• The Drive home, very similar to the drive to work.
• The car is level again and the light level drops as well as the temperature.

Anyways, I know it’s boring but it’s neat to see real world events (ones you didn’t know about) show up on the chart.

Update on the Digital Gage

Things are proceeding apace with this as well. The rail and the encoder are attached together and they also slide together with the aluminum part I machined for that purpose. Now as for the board, this was a nightmare. Nothing but problems. I started out with a PIC18F46K80, the faster/cheaper versions of the high end 18f4680 and initially it was all OK. Until I tried to use the UART. For the life of me, I could not get the UART to stop spitting out junk. Once I started getting it to stop spitting out junk, it then output nothing at all.

Now, I’ve switch over to a standard 18f4680 but the LS7166 is giving me problems. aaargh! Anyways, things should improve with a bit of hard work and a fresh mind on the idea.

Imagine my surprise when I discovered the Duinomite. I stumbled across it at dontronics and after reading a bit about it, I purchased it right away.

The Duinomite is basically a single board computer with a BASIC interpreter, VGA and Composite interface and a bunch of other little features which make it so awesome. It should also be noted that this idea was done first by Geoff Graham and his unit, the MaxiMite. It seems as though Olimex and Geoff were having a bit of a fight for a while but frankly, I don’t really know. All I can say is that it’s a really neat device and I’m glad that I bought it.

Anyways, like I said, it has a basic interpreter on it. It allows you to program it with a ps2 keyboard or through the console on a virtual com port. The language itself is pretty rudimentary with no labels except for line number. No functions either. However, for simpler, less time intensive stuff, this board is ideal. Here are some screenies of the video display.

The video is pretty rudimentary, monochrome only, 324×216 or 320×200 in vga mode. It does seem to work ok though. The nice thing about this device is its easy access to a sd card so you can log data as well real easily.

anyways, I thought it was a neat device. anyways, check it out at http://www.olimex.com/dev/index.html

Data logging

As a side effect of trying this board out, I kept a couple of graphs. The first on is temperature versus time and the next is light level. I just wanted to try it out so I left it run overnight and here are the charts

I did something like this earlier, like 3 years ago. I’ve always found it neat to see such variation in a controlled environment. For example, the temperature graph shows when I closed the door to my office, the temperature dropped but you could see the furnace kicking on every 20 minutes.

Also, with the light. You can see I had the main light on. Then I turned it off. Then i left the monitor on when I left, eventually the monitor turned off and then as day broke you could see an increase in lighting.

I dunno, I think that kind of thing is cool.

These boards aren’t including the mps430 board, the pic boards, the mikroelectronika board or the Friendly ARM. Too many boards, not enough time. I’m sure I’ll use them for something I guess. Tomorrow begins the fun of interfacing the LS7166, it shouldn’t be too difficult.

The device itself is dead simple, simply find an old speaker you never use, preferably a small one so that you can drive it from the output pin. Using a small battery like I have there, you could probably let the device run for about 30 days. Here’s the design:

dead simple, once again. Only one output is used on this device, I even disabled MCLR so that there is no extra resistor. Just one cap for decoupling and one cap for producing a larger waveform for the speaker. You can change the cap size if you want, you may want a larger cap for a bit of a smoother wave. So, here’s the pinout and the source code and .hex file

• GP0,1,3 -> Not connected
• GP2 (pin 3) -> to speaker

Source and hex: 10f200 annoyo src.zip

Anyways, a couple of notes. This program was written with Oshonsoft basic. Also, it could have been written a bit smaller if I tried but as it stands it takes up 253 of 255 bytes available in flash.

Hope somebody has fun with this!

The concept is simple, have a knob that produces no waveform in the middle of it’s stroke and as the pot deviates from the center, the speed of the signal increases also changing direction based on which side the knob id turned to. I couldn’t use a PIC10F200 much to my chagrin because it doesn’t have an ADC module built in, the PIC10F222 does however. It still works within my concept of low-end mcu’s doing valuable jobs since they’re still only 55 cents in quantity, from digikey of all places.

Overall, it’s a pretty simple design.

• GP3 -> unconnected
• GP2 -> Channel B out (Digital output)
• GP1 -> Channel A out (Digital output)
• GP0 -> 10k Potentiometer in (Analog in)

Dead simple. I did program a bit of a dead spot in the middle so that one can stop the quadrature from advancing quite easily. I put 2 LEDs on it to indicate that it is in fact working. Anyways, here’s the source (again it’s in Oshonsoft BASIC)

10f222 quadrature src.zip

I didn’t bother drawing up a circuit diagram since it’s such an easy circuit but here’s an additional image if you’re really curious. keep in mind that the board I’m using is Stripboard (aka Veroboard) so the traces run along one direction

Now for the fun challenge of making a simple serial interface MCU to the LS7166.

The problem with some other MCU methods is that people often try checking every 5ms to see if two successive input were high. This is a faulty approach since it can be computationally wasteful and can still produce noise. My approach is as follows:

1. read the input on a loop
2. if the input is high, increment a counter up to a certain maximum (say 90)
3. if the counter goes above a certain amount (say 60) then turn on the output
4. if the input is low, decrement the counter until it reaches 0
5. if the counter goes below a certain amount (say 30) then turn off the output
6. Don’t change the value of the output between 30 and 60

What this does is ensures that there is an area of hysteresis where the noise or bounce of the switch will not generate noise on the output. You can play with the rules to suit your specific need and improve responsiveness or make the output resilient to accidental triggering. This is the reason why for some more important things I have used this method. I have used a pic16f505 for this purpose as well with larger arrays of buttons. Having a programmed method that you can change easily can give you an easy ‘jellybean’ solution for these kinds of problems. Mind you of course when dealing with switches in high noise environments you may need to optoisolate or run TVSs on the switch.

If you’ve read any of my other posts you’ll know that I like the PIC10F200 MCUs simply because of their simplicity and the fact that a lot of people write them off as useless. This design is pretty crude as you can see and that leads me into the topic of the compiler. First,  here is a sample hex file for debouncing - debounce. This hex is programmed to premit a pressed switch to activate after 11ms.

I recently bought a suite of compilers from OshonSoft since I drifted over there out of pure chance. This company is a one man show who sells a variety of BASIC compilers for PIC, Z80 and 8085 processors. I tried the 10f compiler and was immediately impressed with how, for so inexpensively, there was a useful tool for simulation and programming.

I’ve only used the 10f compiler so far but it beats the tar out of PicBASIC Pro, as far as I can tell thus far. Not a lot of frills or gimmicks but it outputs very tight code. Here’s the source for the debouncer pic10f200. You can download a demo version of the 10f simulator at his website.

debouncesrc.zip

Well, anyways, that’s my little treatise on the subject. Also, for those of you on a tight budget and just getting into microcontrollers, Oshonsoft might be a good place to buy a compiler that’s reasonably simple.

Ugluino Being Built

Based off of an Arduino Nano, this guy works just fine. I don’t like using Arduinos for the following reasons.

• Perceived lack of control of what’s going on inside
• Feels like cheating since it’s so easy
• Arduino UI is kind of shitty, especially for larger source files.
• When dealing with AI routines, making it difficult to use multiple files is a minus

Anyways, i plugged ahead and quickly pounded this out with the following IO

• Input – The only one, the Echo pin on the ultrasonic sensor
• Output – Trigger on ultrasonic sensor
• 4 Digital output – for controlling direction on SN754410 Quad half h-bridge driver. These go to two gear motors which are attached directly to wheels
• 1 PWM out for duty on motors
• 1 attached servo out of the servo to turn the sensor

The back end of the Ugluino

Most everything worked out swimmingly until I fucked around with some wiring and produced a short. I hooked the robot on to the USB supply on my computer, I noticed after a few second that the power to the unit wasn’t running… hmmm POOF! Well, as it turned out, there was a problem with the wiring to the ultrasonic dealy and it blew what I beleive was a zener diode

I wasn’t able to figure out exactly what it was, I suspect that it is a zener diode that selects between main power and USB since it is on the output of the VReg. I could be wrong. Since I didn’t have any more Arduino Nano’s I simply tried to fix it and soldered a wire across the offending gap. The device seems to work fine…? Anyways, if anyone know what that part was on the Arduino Nano v3.0, I’d like to know ’cause I couldn’t find the 3.0 Schematics and the design has moved those parts around.

Anyways, The robot moves around based on a very simple algorithm.

1. Stop Moving
2. Scan from 40Deg Right to 40 Deg Left in 10 deg increments
3. return appropriate movement from a function that analyses it
4. execute proper movement (Forward, Backward, Right, Left, Hard Right and Hard Left)
5. rinse
6. repeat

It seemed to work reasonably well. I’d like to build a more sturdy version for shits and giggles so that I can play with the algorithms. I’m probably gonna build one with a PIC18F2685 instead of an Arduino. Also, instead of a single sensor, I will use IR proximity sensors to detect low lying objects. Moving the sensor with the Servo make the robot seem more intelligent than it actually is like it’s ‘looking around’. I quite like that.

Anyways, it’s my first post of the year, considering it’s January 1st and 3:52 am as I write this. maybe I should go to bed. Here’s a video of it getting around.

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!

If you can guess what it is, you get an internet cookie!