Possibly a more in depth write-up later.  For now, we are tired.  Enjoy !

Thanks everyone who participated in the event.  Our booth was a huge success.  If you didn’t make it, here’s a pic flood of what you missed.   To name a few thing’s you missed: Mark’s robot HEX, Eric’s telepresence robot, Jeff’s LaserShark/Laser Pong,  The robot head game, the cornstarch monster,  Paul’s chiptunes streamer/midi interface, Miles and his cardboard robots, an awesome vacuum tube amplifier and the larger part of our redbull creation project!  See you next year!

You must register for this class on Meetup; Limited seating available.

Wednesday, April 17, 2013

You will learn:

How to use a breadboard
What capacitors are
How to use capacitors for filtering power
How to use capacitors for basic debounce/timing circuits
Connect a 555 timer circuit for blinking an LED

This will require the purchase of a breadboard and some more expensive parts that last time (I’m thinking it will be about $15 — I may need to adjust this after I buy the parts). I will bulk-order and get everyone more parts that you need.

700pt breadboard (Like this: )
A few voltage regulators (LM317, 7805) in TO-220 packages
A few 555 timers (DIP-8)
A couple potentiometers (5k, 10k, linear taper)
More resistors (assortment)
Some capacitors (.1uF, 1uF, 10uF)
etc.

I’ll update this as I develop the slides.

You will need to bring:

1 power supply – can be a wall transformer that is between 9 and 15 VDC and greater than 200mA output. You should be able to salvage on of these from any number of places.

22ga Solid Core wire (for connecting to you breadboard)
Some kind of wire cutters. I got some of these the other day:
(Small version – will handle anything that can fit on a breadboard)

Some kind of wire strippers. I like these but any kind that can strip 22ga solid wire is fine.

The parts kit from the last class (need the resistors, LEDs, and multimeter from it) or you can buy a kit for $5 (we may not have more multimeters available if you wait too long)

Either $15 or all of the parts that I listed in the parts section above.

Chris Cockrum will be hosting another class.  This time is for beginning electronics.

There is limited seating available so Please register if you wish to attend.  Wed, March 20th.

Part 1.  Ohm’s law and Watt’s law

This class will teach the basics of voltage, current, and power.  A lab will be included that will demonstrate how to calculate the proper value of resistor to connect LEDs to power.

Parts and equipment may be borrowed from the hackerspace or you can purchase a multimeter (http://www.harborfreight.com/7-function-digital-multimeter-92020.html), a few LEDs, a few resistors, clip leads, and a 9V battery for $5.    Alternatively, you can bring your own.

I just want to thank everyone who helped make the Open House happen.  I want to thank everyone who joined us and hope you come again.

For everyone else, here is a bunch of pictures of what you missed.

We shot lasers, we crashed the go cart, we made beer (not in that order however).  I think everyone had a  good time!

12►

November 17th, 2012 starting at noon MACPOD will be demonstrating his Laser Projector project at the Baltimore Hackerspace Open House. Sign up for the open house on meetup.com - http://www.meetup.com/Baltimore-Hackerspace/events/89508782/

http://macpod.net/electronics/lasershark/lasershark.php

We’re really excited to announce that Baltimore Hackerspace has moved to a new location and we would like you to come help us celebrate.  Come socialize, learn and check out the facility. We will have our projects on display and will be doing a couple workshops. There is also a rumor that there may be food!

If you are attending I invite you to RSVP so we can get an idea of how many people are coming.

http://www.meetup.com/Baltimore-Hackerspace/events/89508782/

When: November 17th, 2012
Time: Noon – whenever
Where: 6410 Landay Ave. Baltimore MD 21237 MAP

It took a lot of hard work to get the kart ready in time for the PPPRS event at Maker Faire NYC 2012.  But we made it!

Needless to say, we learned a lot.  Mainly to get started a little earlier — and not wait until 2am the night before to get the kart moving.

Burnt Mosfets, burnt motors and broken wheels later we made it back home to ponder the next one.  Here’s a video showing some of the races, we had fun.

Last night was a good night for kart construction.  we got a tie rod stretched between the wheels.  it is just a bunch of allthread with some dethreaded sections on the end.  these dethreaded sections make it easier to adjust, since we can just chuck it up in a drill and spin the rod rapidly to get it on or off the car.  It works well enough to connect the two sides together, but needs some tweaking.  Tie rod ends are nuts welded to coupling nuts.

Also related to steering (and throttle, and brakes), someone at the space had the bright idea to cannibalize a razor electric scooter which had a throttle grip, a brake lever, its own self-contained ball-bearing mount, and a telescoping/folding mechanism.  This scooter was a dumpster find but can be found on craigslist for $50, and it also includes a battery, motor, motor controller, wheels, charger, etc which we didn’t use.  I think next year we may see more of these used for steering because when we want to change drivers or if we get in a frontal collision, the steering system just sort of folds away from the driver without actually becoming disconnected.  it’s perfect for us.

Perhaps most importantly, we got all our drive components finally.  we were able to weld the motor mount pods onto the frame and get the motors hooked up.  The pictures don’t show a whole lot, but that’s OK since the mounts need a bit of tweaking and reinforcing at this point anyway.

finally, we turned the original front bumper into a foot rest.  we ran a piece of metal up through it to make it more robust, then welded that piece of metal to the frame.

Here’s a test video.  Next up: iron out the kinks, and add power.

PPPRS test run 1 from Jeremy Ashinghurst on Vimeo.

Progress has been slow.  in the past week we’ve gotten all the requisite parts, but have been lacking in time to assemble it all.

all 4 wheels are now on the kart, and the original body fits surprisingly well.  Fronts are 4″ steel wheels from Harbor Freight, $6.99 apiece with some real bearings in there.  Rears are 5″ azusalite nylon wheels from a member’s gravity car.

some of our drivers, too, fit surprisingly well.  We’ve had to widen the roll cage a bit to accommodate adults, and we removed some of the crossbars from the existing ‘rollcage’ so they wouldn’t interfere with seating position, but aside from that the exterior of the body is just about completely stock.

the body rests on a simple frame of angle iron.  It supports our vertical loads well, and is torsionally flexible.  This is good because it will serve as rudimentary suspension and will prevent the castered front outside wheel from coming off the ground under cornering.  The front wheels have caster so they experience negative camber during cornering, which should allow the tire to maintain a proper contact patch.  While we expect understeer due to the relative dearth of weight on the front axle compared to the rear (and the better tires with a larger contact patch on the rear), caster should help mitigate it.

Power will be delivered to the rear wheels from the EV warrior motors via #35 chain.  Attached to the rear wheels are 60-tooth sprocket drums.  Since these are also part of the braking assembly, their cost is not counted toward our $500 target.  The donor kart did not need a chain drive so we had to remove the original brake drums to make way for the new ones.  brakes are azusa 4.5″ drum assemblies, also from the gravity kart.  they will be actuated by a hand lever on the steering yoke.

We even have comfortable seating worked out!  A member brought over many, many office chairs so we a good selection to pick out the sturdiest, perfect-fitting seat.  with the nature of the seat and the posture, the kart is surprisingly comfortable to sit in and feels stable as well.  The body has been cut out to lower the bottom of the seat to within an inch of the minimum ‘axle height’ rule.  this, combined with the slightly laid-back posture of the driver, should keep the CG as low as we can get.  perhaps we won’t need the frame extensions we’ve kept on for provisional wheelie bars!

Now it’s on to drivetrain and steering.  we hope to have the thing rolling by the end of Wednesday night