VEX Robotics Analog Accelerometer V0.5

**Hey Guys,
I’m happy to announce the Vex Analog Accelerometer is now available for purchase.

By measuring the acceleration of the robot, one can calculate the velocity of the robot, and more importantly the distance this robot has travelled. **

Yes! thank you! i’ll take 1. did anybody notice, though, that a 36" pwm cable costs the same as a 6"? strange, huh…

when’s the gyro going to be out? i need a bigger sensor arsenal.

Very interesting! The selectable sensitivity is a nice touch.

This appears to be the first “bare” VEX electronics product we’ve seen. It doesn’t have an enclosure or the traditional built-in cables. It looks much more like a sensor from Lynxmotion, Sparkfun, or Parallax (but with VEX-friendly pinout and mounting holes, of course). I wonder if this is a new direction for the VEX line, or if this is just because it is a “V0.5” product.

It may be a bit less friendly to less-experienced builders, since there isn’t anything preventing you from plugging the cables in wrong, nor is there any protection over the electronics. On the other hand, a 3-axis accelerometer is probably most interesting to more advanced builders.

Personally, I like the design because it is smaller and lighter than it would have been if it were fully enclosed. By having the mount be directly to the PCB, you get the best coupling between your chassis and the sensor element - PCBs in a plastic enclosure have some play that may effect the readings. Lastly, since I may not need all three channels on every project, the lack of built-in cables means no loose wires.


  • Dean

It does seem odd at first glance, but if you ever make cables up, you’ll find that the effort involved is the same regardless of length.

I suspect the bulk of the product cost is in the labor, connectors, packaging, etc. The cost difference is probably only a few cents between the various lengths.


  • Dean

I for one welcome our new “V0.5” bare metal parts. If it means I get access to Vex legal stuff 3-4 months faster than ones with red plastic then I’m happy.

It’s a more advanced component and I think I can manage the students with a little more care on mounting location. (Even though I’ve not been successful at the FRC level getting them to do that.)

OK, IFI, how about that decent “V0.5” IR sensor like this one? Sharp gp2y0a21yk

We try to walk that “Vex legal” line as much as possible, and it’s a great product line, but we are always looking for new sensors.

Can the acceclerometer measure tilt like in the iPod Touch? Or is that the gyro?

Will there be a programmer’s guide soon? :slight_smile:

It should… the gyroscope measures change in rotation + position around an axis, whereas the accelerometer measures change in speed + position in a direction (X, Y, Z axes)

There ARE different accelerometers with different specific purposes, but this is what i know.

OK cool. But how do you program it? What do all of those features mean? What are the two extra pins for? :confused::confused::confused:


There are three outputs, one for each axis. You use a servo cable to attach each axis output to one analog input port on the VEX Microcontroller.

You can find the current acceleration along each axis by simply reading the analog port. Presumably, a value of 511 would mean the sensor was at not accelerating on that axis. Larger values would indicate acceleration while smaller values would indicate deceleration (or, acceleration in the other direction)

The two extra jumpers allow you to select the sensitivity of the sensor. You add or remove the jumpers to select between one of four options: ±1.5g, ±2g, ±4g, and ±6g.

EasyC Pro has a sensor block for the accelerometer, but I haven’t looked at it yet.


  • Dean

So buy the 36" cables and Zip Tie them to the proper length. :wink:

Thats what I do. I have some 6" ones for when I need to s-t-r-e-t-c-h the cable just a tad. For everything else, I use 36" and a zip tie.

  • Dean

Well, I guess I will put in my 2 cents about the new VEX Accelerometer - I hate it!

I’m sorry to be so harsh and I know some of you like the bare board design, but if I wanted a product like this - I would have just built one myself or bought one from a hobby robotics site. I have a lot of time and money invested in my VEX parts and I was expecting a nice finished product just like most of IFI’s other ones.

If Lego Mindstorms can have their accelerometer in a nice housing then why didn’t IFI put the VEX Accelerometer into a nice housing just like their other sensors?

They definitely dropped the ball with this product as far as I’m concerned. I was really anxious for this one to come out, but I won’t be buying this one! To be honest, I’m just bitterly disappointed - I expected better from them. Besides, with the metal frame work of the VEX system, I would think having an exposed circuit board, especially in a competion, would just be asking for trouble.

If this is the direction that IFI is taking with their new products, I guess I won’t be buying any of them. Sorry, I just feel really let down and I’m venting my disappointment.

I have to agree I could by an accelerometer from another company cheaper and smaller. Why use the vex one, it is vulnerable to damage. I can just see one mounted onto some beam and getting hit from the top and the whole mounting holes part break off of the circuit part. Suddenly it is lost. Either some cheap and quick shortcut was taken with the development of this sensor or VEX is going in a different direction with its parts, if future sensors will look like this one.

First you guys want the products now. Then you say you want them to put more time into the product. You can have one or the other but not both.

The accelerometer is not meant for the average person. In order to use the accelerometer you need to have some degree of expertise with programming and along with that you need to be able to know how to use it. What to plug in and where. I bet that this kind of person will know how to take care of a board and not have it break on them. Another thing is that by no placing it in a case they leave more options open to the user and keep the price down.

Be happy with what you get, you asked for an accelerometer and you got one. You got a good one too with multiple setups. I like it you should too.

Thank you IFI for improving the VEX line of accessories.

I agree. And note that this is v.5. So it’s halfway done. You can always create a case for it, wrap it in electric tape, and write little notes on the bourd of where the white wire is. You just need to put a little work into it.

Thanks! Now I get it!:):smiley:

I’m sorry, but I totally disagree!

I would rather have them take the extra time to come out with a product consistent with the overall style and design of the rest of the VEX products than to rush something out.

It may be a great little circuit board, but by no means tell me that I should be happy with a half way job! How much extra time and money would it have taken to develope a nice accelerometer in a red & gray housing just like the other sensors. I have been waiting since last May for this sensor to come out and if I wanted something like this, I could have bought one from one of several online vendors long ago.

I guess I hold them to higher standards than the rest of you. I expect them to take the time to develope good quality products consistent in design and style with the rest of the VEX Robotics Design System. I don’t think that is too much to ask.

What I don’t expect is a collection of whatever mix-matched parts that they happen to come up with. If I wanted to have that, I would have just bought individual parts and built a robot from scratch. They definitely missed the mark with this product and we shouldn’t let them off the hook for that. They should have done better and if we don’t hold them to high standards who else will.

Advanced users aren’t the only ones who might what to use an accelerometer and reguardless of who uses it, I think a housing is just a good idea - plus it looks a whole lot better!

The VEX Robotics Design System got off to such a great start when it first came out at Radio Shack - all of the accessories were well thought out and consistent in design and style with the rest of the system. It still has such great potential and I don’t want to see that wasted.

Sorry for the long post, but I just had to express my views about this even if they might be contrary to the majority of the members. I’m a 44 year old adult who believes if you are going to do something then you should do it right, not half way or whatever is quickest, cheapest, or easiest just to get it done. I guess that I am just old school.

It’s out as a “V 0.5” item. Those that want to get it, learn about it, and are willing to be careful with it can have at it. Those that need it in a box with the wires can wait for the “V 1.0” version.

From the spec sheet and looking at the picture, it does sound like it’s a well thought out item. All the jumpers are there and the values should be in the right range for the Vex A/D converts. So it should work well with the control system.

I think it’s great that we are getting the offer to get it early. I’d rather have it now, but I will order the plastic covered version when it arrives.