R/C Bot Takes Your Strawberries Away

Don’t let the friendly smile on this RC cart fool you, it will take your strawberries away — though that’s kinda the point. It’s an RC car that [transistor-man] and a few friends modified for carrying freshly picked strawberries at strawberry fields so that you don’t have to.

RC strawberry carrying robot before putting on the cooler
RC strawberry carrying robot – WIP

They started with an older Traxxas Emaxx, a 4-wheel drive RC monster truck. The team also bought a suitable sized water cooler at a local hardware store. A quick load test showed that 5lbs collapsed the springs and shock absorbers, causing the chassis to sink close to the ground. The team had two options: switching to stronger springs or locking out the springs altogether. They decided to replace one set of shocks with metal plates effectively locking them. After that it was time for some CAD work, followed by the use of a water jet to cut some aluminum plate. They soon had a mounting plate for the water cooler to sit in. This mounting plate was attached to 4 posts which originally held the vehicle’s Lexan body. A bungee cord wrapped around the cooler and posts on the mounting plate holds the cooler in place.

Thermal image of bad MOSFET
Thermal image of bad MOSFET

Some initial testing showed that the vehicle moved too fast even in low gear and tended to tip over, as you can see in the first video below. Some practice helped but a 3:1 reduction planetary gearbox brought the vehicle down to walking speed, making a big difference. A trip was arranged to go to local strawberry picking field at Red Fire Farms, but not without some excitement first. At 1AM the UNIK 320A High Voltage Speed controller emitted some magic smoke. A quick check with a thermal-camera found the culprit, one of the MOSFETs had failed, and after swapping it with one that was close enough they were back in business.

As you can see in the second video below, testing in the strawberry field went very well, though it wasn’t without some tipping. Kids also found it a fun diversion from picking strawberries, alternating between mock fright and delight.

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RC car hack saves lives in war zone

R.I.P sand-colored radio-controlled truck. Your life ended with a bang and in doing so, saved some lives. This little work-horse is a hack that [Ernie Fessenden] put together and sent to his brother [Sergeant Chris Fessenden] who is on a tour of duty in Afghanistan.

[Chris’] team is trained to be on the lookout for roadside bombs, but [Ernie] wanted to sent him something cool that could also keep him safe. By adding a camera to the hood of the Traxxis Stampede and using a gun-mountable LCD screen, the soldiers now have a way to see what’s on the road ahead from their armored Humvee. Sounds like it would work just fine right? Well the hack just got a big endorsement when it tripped an IED made of around 500 pounds of explosives. [Chris] and five other soldiers on patrol were unharmed in the event, and [Ernie] already has a replacement model on the way.

[Thanks Rioexxo and Alex]

More proof that battlefield hacks deserve a place next to some of the high-ticket items you’d usually associate with weapons of war.

Autonomous rover roams the halls

[ESylin] built an autonomous rover that roams the vacant halls of his school. On the hood of the vehicle he’s mounted two Maxbotix sonar sensors that do a great job of keeping the vehicle centered in the hallway. It will follow a wall around a corner (favoring its left side because of the left-facing sensor) and it will stop to correct itself if it gets off course. That’s because when you’re not driving a dsPIC33 is, with a Traxxas XL-5 speed controller and a hobby servo for steering. But this little guy hasn’t lost all his pep. Manual control and be switched on from from an R/C controller so you can burn up the floor tiles. Take a look at the demo after the break, with the manual control demo shown at about 4:10. Continue reading “Autonomous rover roams the halls”