Refrigerator Controller-Thermostat

A bit back I opened my office mini fridge and found that it was warm. I checked all the obvious things: it was plugged in and getting power, and the thermostat was set correctly. Deeper diagnostics revealed that the thermostat was faulty. No matter the thermostat setting, it was not engaging to cool the fridge. If I bypassed the thermostat and manually (i.e. shorted the compressor leads) started the compressor the fridge cooled as it should.

I was unable to find an OEM replacement thermostat but figured I could make a replacement for less than a new fridge would cost.

Refrigerator Controller - Thermostat

Continue reading

Automatic Server Room Exhaust

The Problem

I have a home “server room” that houses a couple of servers and other network hardware. In fact this site is being served to you from a VM running on a server sitting in that room.

If you’ve spent any time around servers (or any electronics for that matter) you know that they generate heat. I’ve recently consolidated a couple of physical servers by virtualizing them but the remaining physical servers, switch, cable modem, and UPS still generate about 2000 BTUs of heat. That’s about the same heat output as a small space heater.

The “server room” is a repurposed 30sq foot bathroom that is off of a main room (think of the typical master bedroom/bathroom setup). Managing the heat produced by the equipment has been an issue mostly solved by keeping the server room door open (to keep heat from building up) and running the existing bathroom exhaust fan.

My main issue with the current setup is having to keep the server room door open. This is especially an issue in the summer because the heat produced from the equipment is enough to overwhelm any cool air being pushed into the main room from the central AC. This makes both the server room and the main room perpetually hot. Also annoying is the noise from the equipment, and having to keep the door open prevents me from being able to doing anything to reduce dust incursion into the server room.

Continue reading

Mailbox Notifier

Note: since the original posting, I’ve added some updates (bottom of page).

A couple of years ago I came across some vintage light bulbs while perusing the aisles of Home Depot. Since then, I’ve been looking for a project to use them in. I thought that it would be cool to use one as an indicator light and started to form this picture in my head of what it would look like. I wasn’t sure what the bulb would be indicating, but the idea was now in my head and once I figured out what to use it for, I’d have to make it.

All that to say that this project was motivated by the need to make an indicator light using one of those vintage bulbs.

Continue reading

Cheap Incandescent Headlamp Conversion

Harbor Freight sells these cheap incandescent headlamps for like $3.00. For what they cost they are not half bad. Still, I’d prefer an LED over the incandescent bulb.

The incandescent bulb the HFHL uses.

I had one of these Harbor Freight headlamps (HFHL) and a broken1 LED flashlight. The flashlight used a 1 watt LED mounted to an aluminium PCB. The flashlight’s driver still worked too so I used it and the LED to convert the HFHL.

Continue reading

Lighted Address Numbers

Lighted Address Numbers

A while ago the Wife Unit™ found some decorative metal numbers in a sale bin at the store. We both thought that they’d make great address numbers for the house and since they were dirt cheap we, bought them.

It didn’t take long for me to decided that I wanted to do something more than just hang them on the house. The numbers are raised, sort of reverse embossed, so the edges are exposed. My thought was to back-light the numbers for a cool nighttime effect.

Continue reading

Coin Operated XBOX

I’ve had several people ask me if I make this for them. The answer is yes, I can… But. It costs a lot. Assuming that you didn’t have any parts (wire, microcontroller, buttons, etc) on hand, it would cost you roughly $200 in parts to make this. Perhaps a bit less as that number has fairly generous margins for miscellaneous things like wire, screws and wood. If I made it for you I’d have to charge for the parts, as well as a labor and the cost of shipping it to you… The total cost I’ve come up with each time I’ve looked at it is just north of $400 (not including shipping). That’s the cost of the parts, getting them shipped to me, plus a margin for part price changes/error. So, yeah, it would cost a lot for me to make one of these for you. If that price seems outrageous, I sympathize. Unfortunately, I can’t make the parts cheaper and my time is valuable, so if I’m going to make one of these for you, I’m going to want something in return. As it turns out, money is the thing that I’d want in return. So, if you see that $400 price tag and you’re still interested in having me make one for you, by all means get in touch with me. Otherwise, I highly recommend that you make one yourself, if you can manage to scrounge up some of the miscellaneous bits and pieces (buttons, wire, enclosure) you could make this for way less than $200 and I’d bet dollars to doughnuts you’d have fun doing it.

We don’t have any issues with our Child Units™ (CU) playing video games. No fears of them turning into mass murderers or anything. However, the XBOX has a way of making our CU’s oblivious to the rest of the world. This creates all manner of issues, from the dogs not being let out, to chores not getting done at all or completely.

I started to think about a way to control access to the XBOX – the length of time it could be played, a way to forcefully stop game play at set intervals, and make it so that playing it was something you had to earn.

While the XBOX has “parental controls” they don’t work the way I’d like them too. You can set content restrictions and on-line restrictions but can only set a daily or weekly play limit. So, I could broadly limit the amount of playtime but I wanted more granular control and was looking for a way to stop game play and say “Let the dogs out!” or “Go finish the dishes!”

I almost immediately thought of a using a coin or token system as the access control. I took to Google, I was sure someone had done something like this already.
Continue reading

2013 Pinewood Derby

This year the youngest Child-Unit did the Cub Scout’s Pinewood derby again. Like last year he designed the car and I helped him with the electronics.

The fading LED was done by using a 555 timer. I believe this schematic is close to what we used. The only real difference is that R1 in that schematic was replaced by a trimmer pot so that the fade speed could be adjusted.

Power was provided by 3 CR2032 batteries connected in series for a total of 9 volts. The dome was just a scrap piece of plastic, with two metal pieces from a hard drive glued to the ends.

Unfortunately, this was one of the slowest cars at the race with a top speed of ~5.8 MPH.