Category: Hobbies

Things I do for fun

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Project: Camera intervalometer

I’ve decided to embark on my first circuit design project. Going to try to build myself an intervalometer that I can use with my camera.

My plan is to take what I’ve learned (and will learn) about 555 timers and try to build a circuit that will generate pulses at variable intervals. The pulses will (somehow) short a connection to ground, triggering the camera shutter with each pulse.

Sure, I could do this the easy way and go with one of the many designs posted at places such as Instructables, but coming up with it myself will be much more educational.

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Charleston Marathon 2014

Helping out with radio communication support during the Charleston Marathon was a lot of fun yesterday. The weather was on the chilly side with a breeze that didn’t help much. At least it was a sunny day which helped a bit.

I was assigned to the 23 mile mark which, for the marathon course, was also the 17.5ish mark too. It was a while before I saw the first marathon runner come by, about an hour and 40 minutes into the race. There were a few runners trickling by, and then a pretty steady flow of runners over the couple hours going one way, then coming back the other way towards the finish.

The runner in the Superman Underoos outfit gave me a chuckle as he ran by. There was another person wearing a Spiderman shirt, and a woman wearing a 1800s period dress complete with parasol. Probably the most impressive were the two firefighters walking the course dressed in full gear.

Fortunately there were no major incidents (not that I heard over the radio anyway). Had to call for some assistance when a runner broke down at my location but that’s about it. A few other runners broke down at other points in the course but nothing severe.

Just before 2:30PM, the net wrapped up operations and I secured my location. There were only a handful of stragglers walking the rest of the course by that point.

All in all, aside from the temperature, it was a lot of fun. I found out that my HT can reach the repeater on the Yorktown from 8 miles away and that even when broadcasting the time calling signal at max volume pretty much continuously for 4 hours, the battery held out for the entire time. Good things to know.

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Marathon, dog show, hamfest

Lots of things going on the next few weekends to keep me busy.

This Saturday (Jan 18) I’ll be helping out with radio communication support for the Charleston Marathon. If you happen to be near the 23 mile mark, stop by and say hi.

The next CHUUG meeting on Jan 23 is something a little different. Instead of the usual Barcamp style discussion, it’s going to be 5 minute lightning talks on the topic of your choice.

Please create and bring a 5 minute presentation on a technical or geek topic that you are passionate about. If you go after the sacred cows of the geek community, all the better.

Next weekend (Jan 25-26) is the Charleston Kennel Club dog show up at the Exhcange Park fairgrounds. Always a fun to see the variety of dog breeds there. I’ll be there both days in the afternoon with the Charleston Lab Retriever Club (the fun dogs) outside. Stop by if you want to experience what a dog show is like, and then head outside to see the Labs where the fun dogs/people hang out.

The weekend after that (Feb 1) is the Charleston Hamfest and “Computer” Show at the Armory Park Community Center just off East Montague. I’ll be there bright and early helping out in the tailgating area. It’s not a huge hamfest but I should be able to find a few interesting things there. There will be door prizes drawn throughout the day, including three cash prizes (if you’d like to buy a prize ticket, drop me a note). Don’t go if you’re expecting a lot of computer stuff though. It’s just not that kind of show. You’ll find a lot of older “computer junk box” stuff, but if that’s what you’re looking for, by all means stop in. An amateur radio licensing test will be conducted at the hamfest too.

The weekend after that is Orlando Hamcation which was a whole lot of fun last year, but we won’t be going this year. Too many other travel plans coming up to make it practical this year.

There’s also a lot of radio contesting coming up over the next few weekends.

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Decision maker

Lately I’ve taken to browsing my local Radio Shack and “rescuing” some of the clearance items I come across.

Today I wandered in looking for some terminal lug strips and came out with 60′ of hookup wire (can never have too much wire around, right?) and a neat little Velleman Decision Maker kit, both of which were on clearance.

About 15 minutes at the bench, and this simple little kit was all assembled. It’s basically a binary magic 8 ball. Press the button and the LEDs flash quickly, eventually slowing down until one of them stays lit.

Assembled board for a Velleman Decision Maker kit

It’s all through hole components, and is very easy to assemble making it an excellent kit for someone learning how to solder. Perfect for introducing soldering techniques to a kid.

Not bad for $2.

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Binary clock innards

I noticed that one of the lights on my binary clock wasn’t lighting up anymore, and another one was only lighting up very dimly. Thinking that maybe it would be a simple fix to replace some LEDs, I popped it open and have a look inside. It was pretty easy to open up with just 4 tabs to unclip.

Everything is all on one board with surface mount LEDs (labeled D7 – D26) instead of the regular LEDs I was expecting.

Binary clock circuit board

The dead diode is D24, and the fading one is D18.

The six 1N4001 diodes do some rectification of the 9VAC input power. I haven’t traced out the circuit yet to see how they’re arranged.

A PIC16C505 microcontroller is the heart of the binary clock. The other chip above the PIC controller (U2) is a 5V voltage regulator, which provides the power to the PIC controller.

I wonder how hard it would be to find some LEDs to replace the dead ones with.

Update: Traced out the arrangement of the diodes and this is what it seems to look like.

Schematic for the power rectification part of the binary clock


It’s a bridge rectifier taking the 9V AC input and doing full wave rectification