My xxxduino blog.. thoughts?

Hi all, I'm a hobbyist who is using a Boarduino to prototype a camera controller- a project that has been done several times before by several folks. My hope is that I can merge the best of what I've seen, a few new ideas, and make the entire thing a pleasant read- along the ideas of a good Make! article.

Please note that I am writing these entries still, and attributions are being made to folks whose work either directly or indirectly made this possible... for example, David Cuartielles' "Blink" example.

One point I've made early on-- maybe a "true" Arduino might have been a better choice, due to minor compatibility issues I had to work around while using the Boarduino. Overall, these issues posed no real problems for me, but some novice users might not be quite as adept at finding and fixing the issues. Preaching to the choir here, I'm sure!


The blog is at

Nice blog, keep on....

but think about the fact, that has a international Playground. An International Community, an international Board/Forum.

Playground is the place which is able to have thousands of readers, of schematics, of how to do something.

Ahm, i like everything which is related to arduino... so i think blogs and your blog too, are one thing to do a good job of presenting projects and howtodo stuff, but i think you should do the small thing on Playground too...

This is a community... so people shouldn't do their own thing only... but improve CommunityContent (Playground) too....

Go on, with your blog... and consider if you want to enhance the playground too.... that would be a real community help.

Greetings ChrisS

Well there are a hell of a lot of arduino blogs if you look around for them. I am glad there are so many but it means that content is spread around so much.

There is kind of some work in progress of trying to stick all of this together and get a good location for everything.

As most people use either blogger or wordpress, I am hoping that I will be able to set up a 'universal blog' with all arduino blogs linked to it which will show all posts from all arduino blogs and it will then all be accessible in one place.


That thing is called Playground...

maybe there should be an improvement to allow a mixing of blogging and Informationcollecting...

Playground is the Place where Informations have to be.... but it is unconfortable, no Blog thing, and a little bit oldfashioned...

maybe there is a way in punto zero...

or setup a centralised blogserver here on .... so blogs havn't spreaded worldwide on their own....

To make a dictionary for the spreaded blogs seems for me a little bit the wrong way... is the headquarter, and here has to be a possibility to create your own blog... in relation of playground linking... for your actual project....

mmh, has to be, should be, could be...

I think there has to be done much work for the admins here....

mmh... :(

That thing is called Playground...

Well not at the moment it's not. It is nowhere near.

Playground is the Place where Informations have to be.... but it is unconfortable, no Blog thing, and a little bit oldfashioned...

maybe there is a way in punto zero...

or setup a centralised blogserver here on .... so blogs havn't spreaded worldwide on their own....

To make a dictionary for the spreaded blogs seems for me a little bit the wrong way... is the headquarter, and here has to be a possibility to create your own blog... in relation of playground linking... for your actual project....

mmh, has to be, should be, could be...

I think there has to be done much work for the admins here....

Well there's lots of work that could and would happily be done by other people if they'd open up a bit but they seem to dislike letting other people in on anything.

It did seem that this may end up something that would fit into the Playground rather nicely. I'm new to the Arduino platform.. in fact new to microcontrollers in general. I was a SQL and VB programmer for a good number of years, but I cut my teeth as one of those teenagers whose Atari 400 and Commodore 64 had been taken apart and remounted on plywood somewhere around 1980. If I remember properly, my first "Blink" project was 16 LEDs connected to my Atari 400 via the joystick ports (most folks don't know Atari joystick ports were bidirectional!) based on code snippets from "Compute". I bring an odd mix of experience- my knowledge is woefully non-uniform, I am mainly self-taught.. but I have been told I have a way with words, and have been a teacher in the past. I'm sure there are folks who can do a better job technically, and I'm really re-inventing the wheel in many cases, so my hope is that the presentation is the high point of the blog. I try to imagine my fifteen year old reading and understanding and being engaged- I figure that would be a win.

In many ways, the Arduino platform is taking me back to those great times.. these microcontrollers have nearly as much power as many of the first computers I owned and used.. in some ways, they are substantially MORE capable than those systems from long ago.

My hope is that I can combine some mediocre electronics and programming with the words and photos to make it an easy read.. along the lines of a hobbyist magazine, such as "Make!"

As for the blog(s), I'm pretty sure that they can actually be exported- and if not, they can be fairly easily copied over... and would be delighted to have it here. I'm planning to continue it with Blogger, but we can figure a good way to mirror it I'm sure.

The whole Arduino platform is a bit of a playground for me- much to learn, but so much to play with. Since I'm disabled and on a fixed income these days, an inexpensive computer/electronic "Erector Set" like this puts a lot of power and possibilities in my hands. Truth is, I've already begun setting aside money to get a "real" Arduino.. and a Mega also. Having not done much hardware for a few decades, I have very little in the way of parts- so topping the list at the moment is probably a few key items like a mixed component assortment (resistors, caps, etc) and either a DMM or a scope.. not kidding, I'm using a Radio Shack analog multimeter right now. It took me all of three days after getting the Boarduino to trek to You Do It electronics to get another breadboard, a pack of jumpers, the optoisolators, a pack of NPN and PNP switching transistors, a handful of resistors and some pin headers, only the basics.. which kind of depleted the "hobby cash" for a little bit. Since Google sells ad space in the blogs, if the blog gets a lot of views and clickthroughs, maybe it can help finance me putting together a workable bench setup ;D

Arduino has given me "the disease" again... I forgot how much I love the smell of rosin and coffee together...

the Arduino platform is taking me back to those great times

At least I am now thinking about the Commodore PET and the 6502 assembly code challenge/fun.

Arduino has given me "the disease" again...

The world-wide community with help instead bullying/belittling makes this an enjoyable daily visit for me. Reminds me of reading Compute and Cornucopia.

For some reason, I find myself remembering writing Atari BASIC code with inline machine language (yep, 6502) stored in, I even remember my older brother chasing me with murder in his eyes after I had "appropriated" one of his music cassettes (Billy Squire? Night Ranger?) to be used as data storage in that Atari tape drive..

In these days of hardware abstraction layers and meta code, the little Arduino somehow harkens me back thirty odd years to a farmhouse bedroom, where a kid fell in love with the magical device called a "computer" after he spent a summer digging and selling nightcrawlers as bait to buy it. I may be depleting my hobby cash, but at least I haven't resorted to selling worms again. Yet.

That was a long time ago and world away- but the Arduino seems to have captured some of that again for me. Happily, I did a search looking for a cheap way to control a camera recently, and found the Arduino. I'm hoping my strange blend of technical and nonsensical ramble appeals to some.. I guess we'll see. Already, it's clear that it's going to take a lot of thought to keep it both reasonably technical AND engaging. Each entry could easily turn into a detailed programming or electronics lesson, which would lose the interest of a novice reader. My goal is that the details are sought out (for example at in general) rather than trying to do a better job than has been done in terms of a true technical resource. I guess I'm kind of going for that DIY Magazine level of tech, in other words it's enough to get you started but you're going to be looking up details before you're done. Really, back to that familiar "compute" days, where the magazine article was really more of a catalyst and a primer than a finished product. Hard to think of a 28 pin DIP as the source of nostalgia, but there you go, life's weird like that.

I wonder.. how many others look at these with an (odd) bit of nostalgia?

Focalist, I like what you're trying to do. I'd hope you'd come join us @ (It's a community focused on open-source photographic motion control and DIY camera projects w/ the Arduino), if for no other reason than to join in the community discussions.

I think there are a few things you can do to help improve your tutorial process, however.

Namely, I'm left wondering what the content difference (I understand that you're going for a presentation difference) is between your tutorial and the dozens out there for doing intervalometers. I was asked by some of the timelapse guys to do the same a while back, and when I did, I was struck with the same problem, so I chose to focus the tutorial on understanding different timing techniques, which hadn't been covered in the existing tutorials.

It's important that if you're going to cover well-trod ground, that you provide new content. This will really help to draw your readers in and keep them with you.

I have a second, more utilitarian question - your tutorial says you're triggering a bulb exposure of 5mS on the Rebel XT. I think you've made a mistake here -- you may be triggering the shutter at 5mS, but I don't think you've got a 5mS exposure. (If you have, you've just made a bunch of people happy to find a camera that can do very short bulb exposures.) A lot of work has been done on measuring timing on different cameras, it would do well to check on some of the experiences people have had with this:

Finally, it would help a lot to inform your readers why you've taken a bulb-control route, and what the limitations are over using PTP control, much like the Promote controller does - as there are very real limitations compared to PTP control for HDR bracketing.


Well, a large part of what I'm doing is learning- but, I may have a few tricks up my sleeve yet. At the moment, it is very basic- but the idea in terms of the hardware is to have it evolve over time. PTP may indeed be part of where I end up- the problem being of course managing a whole USB host situation. All in good time.

Yeah, I'm aware of the timing.. I'd read that with mirror locked up, the Canon Rebel series could possibly hit 1/200 sec. Since for the blog we're on the first rev and only estimating times, I have to measure just what the fastest we actually get is.

A few things that are planned (and actually have already been tried, most successfully):

Multiple self-calibrating trigger inputs, which can host sensors such as phototransistors, switches or what have you.. Multiple trigger outputs, for controlling processes which will be photographed, strobes, etc.. Unique user interfacing (just wait and see!) Eventual inclusion of PTP and driver for pan/tilt head. Since that implies I have enough cash for a pan/tilt head, it'll be a

Yeah, I know I'm reinventing the wheel-- but if any of us here was looking for "the easy way" to do things, we wouldn't be here now would we? A good portion of Arduino projects are home versions of expensive machines- now we COULD go spend tons and buy whatever doodad it is that we want- but either we can't afford the "real" one of whatever it may be, or even better, choose to take the most self-abusive and fun route of all- making one of our own design. If someone had to pay any of us for all the time dedicated-- any of our projects would be ridiculously expensive. We're all in it for the fun, I guess (I know I am!)

Both my photography and the Arduino stuff are intentional distractions for me. For a while I was into MMORPG's. The situation is that I'm a pretty sick guy- something called Crohns Disease. No need to be graphic, suffice to say there's no cure and it makes you sick, virtually all the time. I'm sick so often and so severely that I finally had to stop working and become Mr. Mom. What I did find is that if I let myself idle too much, or focused too much on what was going on, my mood would spiral rapidly. My hobbies are my most effective antidepressant... self imposed art therapy. Not only am I photographic and electronic/computer hobbyist, I've thrown my hat into the ring as an amatuer psychologist apparently.. lol

I guess in a lot of ways, the blog is just something I'm doing. You'll see what I'm doing evolve, and maybe something truly unique will be the result- or I may just end up re-inventing the wheel in a more convenient and easy to carry rectangular shape. Either way, I'll have found a way to keep my mind off things for a while, learned a few things, and maybe made something useful in the process.

I like your controller project by the way.. I'm a LONG way from finished PCB's, that's for sure! Maybe one way to look at it is that my blog may end up following the journey, without being too worried about the destination, or if there even is a destination at all. I'm just digging the scenery..


i like your post on the canon shutter release. That is probably going to be similar to my first project (after blink).

Thanks. What I'm already discovering is there's a heck of alot that can be accomplished with little more in hardware than that. If you do some searching, there's a lot of miscellaneous articles on things, but it's not been tied together well (or even translated in some cases). I'm trying to tie some of the ideas out there together, to make a whole which is more than the sum of the parts, as they say...

Here's an interesting article on using the arduino as a lightning trigger

and various other triggers:

I love additional blogs as well as playground, both help me out immensly - but a lot of the times its just a picture or a video without explanation, code or parts which can be frustrating sometimes. So it's always nice to see content that's a bit more in depth

That’s what I’m going for- kind of that old serial magazine article feel. There are much better coders and engineers out there, but many of them don’t have a great writing style. Having a bit of fun doing it, which is satisfying my own personal goals.

Newest entry shows some successful HDR shots, some lessons learned, as well as a code revision based on what we learned.

Bit ill today so probably won’t make it out for another session at Wayside to test the updated code- might try it out indoors (which will likely require some changes too) or start the discussion regarding light sensors- whether we could use a photosensor to autoset the HDR exposure range. The photosensor post will be large- there’s a lot to cover there- from lightning photography, to Infrared “triplines” and all sorts of fun we can have by adding about $5 in components and some code to exploit it. There’s so much you can do with a Radio Shack phototransistor and a little code…

Interestingly, I’m now thinking about how (down the road) I may want to do a reductionist version- maybe here- containing just the “final” code and circuitry. In the end, by combining a number of ideas, I’m hoping this device turns out to be unique… but for the technical crowd, some might not want to wade through pages of my blather, and just want the good ole “code and wire only”…

Okay guys, I'm prototyping something at the moment- I think I've got a novel approach, and it SHOULD work. I may throw the circuit up here for comment before the actual blog.

One thing we see is need for sensors. Light and sound, in particular.. but really, a whole host of input jobbies would be nice. Problem is, our Arduino's inputs aren't quite "all purpose".

What I'm working on is an autoranging analog sensor circuit. Basically, I'm amplifying the input and rectifying with a kind of Automatic Gain Control controlling, so when a sensor is connected, the amplifier sets the gain to a squelch state, which then maximizes sensitivity automatically. Basically anything with a low level output could then be connected, ranging from a simple electret mike to thermocouples to line-out from a specialty amplifier. trying a couple of approaches, got a handful of parts which should suffice- 741 op amp, a quad opamp, a quad comparator, a low power audio amp (gain up to 200), a handful of mixed transistors, and a dream..

I'll probably be able to bash something together out of that which will work. I'm considering whether I might use a PWM output to create a analog out via a cap, controlling the base (gain) of the amplifier instead, also. I really kind of like putting the gain under program control, for a lot of reasons... not the least being it would be a LOT easier to control and possibly even calibrate to a certain degree. Structurally, I know what I want to pull off and think I should be able to find a working solution with what I've got in hand. Since I'm planning to drive the analog port, delta detection can be done in software as long as we get the signal to the pin. There's enough room and flex here that a working design should be possible.

Any of you circuit guys got any great ideas on this?

I want to have these low-level active amplified ports be as versatile as possible- we aren't looking for audio fidelity for example, we just want to see a peak. Same with the light sensors. Calibrated input isn't the need- a way to detect changes in the input level is all that's needed. Overamplification isn't as bad a problem as it could be, clipping is not a worry.. just maybe too many false triggers. The PWM-controlled gain is something I've been thinking about in terms of phototransistor sensors and the like also. Ideally, you could connect virtually any sensor (from a simple switch to a phototransistor to a microphone) to the same circuit, and we'd configure for it automatically. That's a little more tricky and honestly going to leave me circuit searching... Man, I really should have gotten in more than one semester of electronics....

I want to connect a sensor, press a switch indicating the sensor is in quiescent state.. and from then forward, it should be done in most cases.

Kludges are fine :)

I really kind of like putting the gain under program control, for a lot of reasons... not the least being it would be a LOT easier to control and possibly even calibrate to a certain degree.

Interesting concept and would be very useful. So far I haven't seen any shield mounted general purpose analog conditioning circuits. What little analog circuits I have seen tend to be specific to a certain type of sensor, like thermocouples or rtd sensors, etc.

The idea of using a filtered pwm output for setting the gain is a good idea, however I would add that a second filter PWM output would also allow for 'programmable' offset control of the conditioning amplifier circuit, which is also required if one wants to maximize A/D resolution for any given sensors true range.

Another method of 'auto-ranging' might use a filter pwm output to drive the A/D aref pin and using the external reference statement in software, that is equivalent of adding gain in an external amplifier I believe.


Aha! Now see, I hadn't even looked at what aref was. There's one hell of a game changer right there in a lot of ways.. I hadn't even considered changing reference voltage and even worse, wasn't aware it could be done programmatically, at least to the 1.1v internal reference. That alone goes a pretty long way, and like you suggested- filtered PWM might be ideal for providing a really slick way to control "external" aref. VERY interesting. Every time I turn around, I like Arduino just a little bit more. If you end up following what I do, you'll see my expertise is just enough to make me dangerous, but not quite enough to make me useful.. things like I'll fall down on a complex build because I'll have forgotten a bias resistor or some silliness.

Considering the number of analog input circuits I see for the Arduino, I find it amazing this hasn't already been done.. or maybe I just didn't look in the right places. At least if we get a good solution now, we can crosspost it over to the playground "interfacing" section. Seems like we have a chance to improve upon the wheel (I personally like them rectangular, so they are easy to carry).....

I wonder.. how many others look at these with an (odd) bit of nostalgia?

focalist, you're not alone.

While I didn't have to sell bait as a kid to get my TRS-80 Color Computer, I do remember the summer days and nights spent coding in front of a 19 inch television, playing video games on that thing, reading my stash of Rainbow, Compute, Hot CoCo, etc magazines, and dreaming.

That was over 20 years ago. I am still somewhat "active" with my Color Computer; there are still many enthusiasts of it (check out and to see a glimpse of what a couple of them are doing, if you care). My "claim to fame" is helping to resurrect an old "Ultima" clone game called "Gates of Delerium" from the ashes (and in the process getting the old company that made it, Diecom, to release their catalog of games to PD).

At some point, I have a plan to interface my CoCo 3 to my Arduino; not sure if it will be via the bit-bang serial port, or the cartridge slot (via an RS-232 adapter cartridge, most likely) - I intend to use it for control of a robot arm...

The Arduino has the same feel and character as those old 8-bit machines, certainly. For me, though, I use it mainly as a controller interface for robotics - if I wanted to explore old 8-bit stuff, I have plenty of old hardware for that (my old CoCo systems all still work, floppy drives included, and I have a bit of new hardware to expand the system - plus I have an old Altair just waiting for restoration).