Last year my team tapped a sheet of lexan to bolt our electronics components on, and although the end result was very spiffy it just took too long.
For a test robot this summer we had to wire it for a demo in about 2 hours, so stripped for time we decided to use industrial adhesive backed velcro to secure all of the electronics components and it worked great! This was on a robot that could flip itself upside down, it took a lot of jolts.
Of course we don’t plan to velcro down a cRIO, but for the digital sidecar and victors it could be nice. So my question is. . . would this be allowed under the 2008 rules?
We have used velcro to mount our electronics in the past and they have worked great, but i like bolting them better since they wont end up straight with velcro.
My team uses velcro every year to mount electronics, so it has been legal in the past. However, with the new control system they may change alter these rules. So honestly, nothing can be said for sure until we get the full game manual.
Using velcro may result in weight savings compared to using machine screws to hold the electronics in place, at least if you are using steel screws. We switched from using #8-32 and #4-40 steel screws to the equivalent nylon screws a few years back and saved, as I recall somewhere on the order of one pound.
Industrial-strength, adhesive backed velcro should be available at your local hardware store. I usually get ours at Rona or Home Depot. It is also great for securing lexan body panels and many other parts that may need to be repositioned.
Quick Tip: Don’t use Velcro, use 3M Dual Lock (See: http://www.itapestore.com/index.asp?PageAction=Custom&ID=19) It’s the same stuff used on the FLL fields to hold on the Lego models. It has a higher tensile strength and has "five times the strength of standard hook and loop. Plus, since it adheres to its self you don’t need to worry about having two different sides. It will also adhere to regular “loop” side velcro.
I just went to the Home Depot and got some of the ‘modernized’ velcro - the industrial strength version. I do not know for fact but it possibly compares favorably to the 3M stuff.
This year I wouldn’t try to Velcro the Crio due to its weight, I’d be worried about it flying off in a sudden stop. It has a couple mounting holes for bolts.
I’ve been using that Velcro Industrial stuff (industrially, for FRC and for other things) for years, and I’m very pleased with it. I would estimate that it’s stronger in tension than Dual Lock (although not quite as simple to separate). 1114 and 2505 used it to hold down their controls last year, with no issues as far as I know. 1114 even uses it to attach their battery and cRIO. (At inspection, they demonstrated that the main battery was reasonably secure, and were passed.)
The only real catch with Velcro Industrial is that the adhesive needs a while to cure: according to the box, don’t pull it apart for 24 h once you’ve applied it.
Personally, I would recommend against 3M Dual Lock. I was a referee at an FLL Qualifier yesterday and was not impressed with it. It was difficult to keep the Lego models on the mat as the Dual Lock was not holding very well.
I would agree that Velcro is not a good choice for either the CRIO or the Power Distro. We have used it in the past for things like the Spikes and Victors but be advised is it good for a year or two after install but then the adhesive starts to dry out. Tywraps are an excellent choice but I don’t think they will support the CRIO. I would expect that the inspection list will include a line item for secure mounting of the controller, the PD and the wireless access similar to the mounting for the main breaker and fuse panels in the past.
1618 has used Velcro in copious amounts during my time with them. A tip: standardize which side goes on which part. You don’t want to be scrambling to attach a replacement Victor that won’t stay put because you mixed your hooks and loops up when you installed it the first time.
I have seen a Spike that was attached with Velcro to the inside top of the electronics box come loose in a good impact. Of course, it landed on something bad, resulting in a fair amount of magic smoke and a giant bundle of wires that were melted into one chunk.
Use care if you are going to mount things with Velcro. If bad things can happen if it comes off, you should at least put a wire tie around it before competing.
Our team has used a LOT of velcro (too much!) and it seems to work alright for components that are not critical like spikes or sometimes victors. I don’t think that velcro on the cRio is a good idea just because of the weight but for the power distribution panel, it should work provided you use the 2" wide stuff and not that small narrow velcro.
I don’t think we’ll ever use Velcro again. In '06 and '07 we used velcro, and replacement was just a hassle sometimes since the velcro backing doesn’t always like to separate from the velcro…and as previously suggested alot of times our velcro sides didn’t match up.
In 2008, we used #8 and #10 nylon screws. With nylon screws you can drill a hole, hot glue the nut in place on one side, and effectively have the equivalent of a tapped hole. For 2009, we’ll probably use rubber-backed washers with steel nuts & bolts for the cRio, and varying sizes of phillips-head nylon bolts for the rest. All will be mounted on honeycomb fiberglass that will have a nice glossy finish put on it in the end.
For the cRIO & PDB, think about the risk vs reward. You’ll save a few ounces at the risk of an imperfect <adhesive> connection coming loose. Should the risk come to fruition, the consequence is that you may have to replace a several thousand dollar part that you’re supposed to also use in future years’ FRC competitions…not just 2009. Is it really worth the risk?