Every parent knows early on what it takes to make their child happy. When that child is autistic, those things may be somewhat different. My son happens to find certain things fascinating that most children couldn't care less about. Signs are the number one thing he likes to play with. He likes to touch every exit sign in every building we enter. This can be difficult to do most times which is why I made him his own on the small scale. After making that one, I realized I should've documented its creation to post on this site. But recently he's been asking about a flashing orange sign he sees every day while on his way to school... so here's that project.

Tools needed:

- Soldering Iron

- Dremel Tool (with cutting wheel)

- Hot Glue Gun

Parts needed:

- Altoids tin

- 2N3904 transistors x2

- 100K ohm resistors x2

- 470 ohm resistors x2

- white LEDs x2

- 10mF capacitors x2 (voltage not really important)

- 9v battery with clip.

Step 1: Pick a Design

What you have to start with is an image of what you want to recreate. I used a simple arrow lifted from somewhere on the web. You can scale it to the size of your project box (I used an Altoids tin) by using some program that will give you the measurements of your picture. I used MS Word, but there are many. You can always use trial and error as long as it's not your ink. =)

Step 2: Transfer to Box

I used carbon paper to transfer this image onto my project box. You can pick up carbon paper at most any office supply store. I also painted the box first... for obvious reasons. You might notice that I altered the picture slightly. This will make it easier to cut out later. You may want to consider this when you decide on which image to use. This one was very simple.

Step 3: Cut Away

So what's stopping you from cutting the necessary hole in the box where the light will shine through? That's right. Nothing. This is probably the most difficult part for most people (unless soldering just isn't your thing). I used a Dremel tool for this. I'm not sure what you'd use if you don't have one. Just be careful not to leave any sharp edges if you're going to hand this over to a kid when you're finished building it.

Step 4: The Guts

I was wrong. This is the part you'll probably have the most trouble with. I know this because I've received the most questions about the schematic of my last Instructable. Well this time will be different, because you are all experienced hobbyists with a degree in Hobbitry. That's the study of hobbys and has nothing to do with Lord of the Ring. I also stole this schem from another project and have used it more than once, so I know it's a durable design. You should use exactly the parts shown as far as resistors and transistors. (Actually any small signal NPN transistors will work, but the ones shown are about the easiest to acquire). The capacitors, on the other hand, will allow you to speed up or slow down the rate at which the lights blink. A bigger mF and the lights will go slower and smaller will go faster. I actually used 220mF because that was all I had that matched. You can use two different sizes too if you want them to blink sporatically. I did this on another project where that was the desired effect.

Step 5: Put It Together

This is where you solder. Don't ask me how to do this. There are plenty of I'bles explaining this process. You may notice from the picture that I used a 4xAAA holder to power this thing. I glued it to the outside for easy access. "Four AAAs won't produce 9v" you may say. Well the schem is a little misleading there. You can power this circuit with as little as 4v. I wouldn't exceed 9v max though. I used AAAs because I have an abundance of these and not so many 9v. I also added a switch to the circuit. You have to add this to the positive lead from the battery.

Step 6: Assembly

I cut a piece of clear plastic to use for the "lens". I then painted it orange on the inside (because clear just wouldn't do). A hot glue gun is sufficient for holding all the parts in place. I may have to reattach something in a few months, but I don't think there's anything that will be indestructable when it comes to my son.

Step 7: Finished

Congrats. You've successfully assembled a toy your child will cherish for about three weeks (If you're lucky). If you had fun building it, then this could be a good thing. You should start designing your next one right now. You may need to order the parts too, so you better get on that as well. You need to allow time for shipping.

Have fun,

myk