I thought I’d tell everyone about a few larger-ticket items that our team has purchased, that we are very happy to have spent the money on. If you miraculously find your team with excess funds, you might want to splurge on one of these.
SunLabz Battery Charger for Joystick AAAs
Can’t say enough how much we love this item, especially compared to the blue VEX AAA chargers (Amazon: $45). Also can’t say enough about how much we disliked the blue VEX battery chargers. Why do we love this one?
- Charge 16 batteries at once, in any combination of AA and AAA
- Only takes up one plug on the power strip at a competition (or in the lab)
- LCD readout shows a separate little graphic for each battery that indicates how far along it is in charging
- When all batteries are fully charged, the LCD turns off, so you can see from across the room if it’s done
- It’s a “smart” charger, so you can leave it plugged in between meetings
- Has a “refresh” button that discharges the batteries completely; we were able to salvage some batteries that would never fully charge by discharging them and then charging (instead of throwing them away)
Hand-Held Air Compressor
We splurged this year for a hand-held air compressor to use on our pneumatics in lieu of a bike pump; it looks a lot like a cordless drill (right). There are several makers out there, but we chose the Ryobi ONE+ compressor (right). The item itself is only $25, but here’s the catch — it doesn’t include a battery ($39 each) or charger ($42)! So put it all together and you get $106, or $145 if you want a spare battery. Why do we like it?
- It’s fast
- The gauge on the back lets you know exactly when you get to 100psi
- The valve mechanism results in a very small amount of air loss when removing it from the robot
- Kids who weigh 120 pounds have a hard time using a bike pump to 100psi; no longer a problem
- It’s small & portable, and easy to take along to the queueing table, and probably no ref is going to yell at your kids about having it there (you can even put it in your team’s Magic Bag and it’s even less of a hassle)
One thing that is not so great: there is no on/off switch, and it’s really difficult to hold without pressing the trigger button, so we feel the need to remove the battery in between uses.
One other thing to note if you have a big team with many robots: you can only use it for 5 minutes straight, then you have to let it rest for 5 minutes because it overheats otherwise.
See my previous post all about VEX Robot Batteries for a complete description of what this product does. The Battery Beak ($80, + the required $10 connector to attach to a VEX battery = $90 + shipping + tax) is a battery testing device that can tell you more about the health of your batteries than a mere voltmeter or multimeter. When you plug in your battery, it runs 3 tests: voltage with no load, voltage with a 1amp load, and voltage with a 5amp load. It uses these last 2 measurements to calculate the internal resistance (Rint) of the battery. The internal resistance number tells you how healthy the battery is: larger internal resistance means less voltage getting to your robot’s motors.
I’d recommend this item for a team with batteries of various vintages that have been in use for a while. Without the Rint measure, there is really no way of knowing how a battery will perform; measuring voltage alone just tells you if the battery is charged or can be fully charged (which are both *really* important to know, mind you). You’d have to take voltage measurements before and after use on the robot or a test bed to gauge its health otherwise, and it’s difficult to run the robot or a motor setup exactly the same for every battery to get comparable measures.
It is expensive—about the cost of 3 new VEX batteries, so having this device may allow you to hold onto your existing batteries longer, since you’re not guessing as to their robustness.
VEX coach John Nichols from the VEX World Coaches Association Facebook group (which you should join if you’re a coach or mentor reading this) has said that his team’s splurge-and-we-love-it item is a Dremel (he recommends the Dremel 4000-4/34 High Performance Rotary Tool Kit with Variable Speed Rotary Tool, 4 Attachments and 34 Accessories, $96 from Amazon). John says:
My teams have used Dremels with metal cutting blades or sanding drums more than any other tool in our shop. I would saying on average I go through about 50+ metal blades a year, but it’s worth the quality cuts and precision.
One of the dads on our team has one at his house, and used it to cut our long-handled allen wrenches that had become stripped at the ends. I was amazed at the quality of the cuts; you would never know that they didn’t come from the factory. Poof! Extended life for your pricier allen wrenches.
3M Wire Label Dispenser
Not exactly a big-ticket item, but stupidly expensive enough to qualify as a splurge. We bought one of these this year, and I have to say that we love it and are happy to have spent the money on it. It’s the 3M ScotchCode Wire Marker Tape Dispenser ($38, Amazon).
It’s got 10 individual rolls of tape (one for each digit, 0 through 9), with a metal toothey-ridge running horizontally across the whole thing (like on a box of saran wrap). Each roll of tape is just a continuous string of the given number: 3 3 3 3 3 3 (vertically along the tape). So you just peel off a little section, rip it off, wrap it around your wire, and you’re done.
Why do we love this stuff? The tape actually sticks to the wires, because…it’s made for sticking to wires. The tape is also very low-profile/thin so that you can have a whole lot of them near each other without it getting out of control, as can be seen in the photo at right. It’s also *really* fast to apply, much more so than, say, pieces of electrical tape or blue tape that requires the kids to write the port number on each piece of tape in each section of wire.
GoPro Hero5 Camera
Another Facebook group coach reports that his team’s big purchase of late was a GoPro Hero5 camera to place on the robot for action filming: $400.[mcafeesecure]