Tuesday, December 8, 2009

Upgrade: LED Hexbug Hack

These photos should show how you can hack your own hexbug to add an LED.

The basic idea was to add a simple feature so the HEXBUGS can play in the dark. Unfortunately the power supply for the hexbug is only 1.5 Volts which really gives you only about 1.3 Volts when the motor is running and the lowest forward voltage of any of the LEDs I have handy is 1.8 Volts. To produce the necessary voltage, I considered a few different solutions but the easiest to implement was just adding another 1.5 Volt battery in series for just the led.


1) First gently pry open the Hexbug. A small screwdriver may help.

 

2) Solder two wire wrap wires in parallel with the motor so that the switch turns off the led as well.



3) Using a small knife cut two notches so that the case fits back together cleanly.

 

4) Solder the wires to the extra battery to get 3 Volts and attach them to the LED. Check polarity. Use CA Glue to attach the surface mount LED to the front of the robot.



5) The battery can be taped on to the back and adjusted for balance. In the future I may try to find smaller batteries that can fit inside the hexbug or blink the LEDs with a storage capacitor.

 

6) Finished!!



Here is the video of it in action.

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15 comments:

Tom A. said...

Wow, I've dreamed of being able to light up a nano with such a simple circuit! I love your video, looking forward to seeing your other projects with the Hexbug nano (if you are continuing). What type of LED did you use?

I Heart Robotics said...

I just used a regular Radioshack red led.

When I am able to find some time, I want to try designing a blinking circuit that can work off the smaller battery which should make it less bulky.

Another experiment to do would be using a pair of light sensors and some Nitinol Muscle Wire to make the hexbug light seeking.
You could probably make the electronics surface mount and fit inside with everything else.

Yet another experiment would be to add a datalogger and use the hexbugs to gather data.

Here is an easy experiment to try (that might destroy your hexbug), use CA glue and/or hotglue to waterproof your hexbug. See how well it works under water. Videotape the results and post them to youtube, email me the link. Perhaps the hexbugs can be used to inspect sewer systems.

You have one week to complete this experiment before I do it.

The bristlebot idea is really interesting and if you think about it there are some really interesting projects and experiments you can make.

I Heart Robotics said...

Correction: That is a basic red 1206 surfacemount LED, you can order them from Digikey. I glued it in place with CA glue.

I Heart Robotics said...

Another easy project might be to add an IR photo-transistor so that the robot only drives when it can see IR light.

That way you won't have to use the switch to turn it on and off.

Wyatt said...

man how do you know how to do all this stuff. And why does it look like the hexbug can only drive in circles?

I Heart Robotics said...

Study hard and don't sleep.

This Hexbug mostly goes in circles because I broke one of the legs when modifying it and the weight is a little off center.

I'm probably going to try waterproofing a Hexbug this weekend if nobody else does.

alfychex101 said...

this could get into somthing important someday,may i suggest you reserch and graph their movements by ataching a pencil lead somewhere?

alfychex101 said...

you guys should try to us apencil led to graph the nano's movement or attach sensors trailing behind to graph the bugs movment mabey you can give it a brain. anyways how many hex bugs do you have i imagian you mess up once in a while.
,thomas

I Heart Robotics said...

I only have two hexbugs at the moment, but I'll probably get more at some point.

I like the pencil lead idea, but I'm not sure how you would mount it without it making a dashed line. Maybe you could sand a pencil lead to make graphite dust and coat the hexbug legs with that.

Another option might to use a camera to track the motion of the hexbugs. The motion of the hexbugs should be related to brownian motion.

http://en.wikipedia.org/wiki/Brownian_motion

http://en.wikipedia.org/wiki/Random_walk

Anonymous said...

here is a tip about making your nano go straight: since your bug is spinning to the right, lightly pull the legs on the side it is turning to .be sure not to pull to hard so you don't pull them off. only pull on the first two legs.

spongebob said...

it'll be cool to have the HEAXBUG lighted up and able to actually move =.= the nano just went in circles XD But its a starter i guess.

Anonymous said...

For the next hack, perhaps a case mod? I'm not willing to tear mine apart, but it looks like the rubber should peel off, I'm sure you guys could do something to make it either closer to the prototypes in look, or better balanced.

I Heart Robotics said...

It's going to take a little while but I have a great idea for a casemod. Probably next week.

I Heart Robotics said...

Anon, please contact us via email for your prize. Thanks.

Reynaldo Natividad said...

The HEXBUG Nano comes with a LR44 button cell which is 11 mm in diameter. I found a 9.5 mm diameter CR927 in the Radio Shack web store that pumps out 3V which would be perfect for replacing the two 1.5V LR44s.