4 ms·

CAN Bus is great. I highly recommend reading the CAN Open Spec if your going to be implementing new systems using CAN Bus. https://en.wikipedia.org/wiki/CANop

CAN Bus is great. I highly recommend reading the CAN Open Spec if your going to be implementing new systems using CAN Bus. https://en.wikipedia.org/wiki/CANopen https://en.wikipedia.org/wiki/CANopen Many more things besides auto's use CAN. One of my current projects involves exercise equipment that internally speaks CAN Bus. There is great support in Arduino for interfacing with stuff like this.

chiph 9y ago
At a previous job I interfaced with hospital beds that used CAN Bus internally. Turns out that Ford had laid off a lot of engineers a few years ago and the firm hired some of them to design the next generation bed. They knew CAN Bus, so they used it to control the hydraulics, pneumatics, lift motors, strain gauges, and so on.
- Declanomous 9y ago
  Man, that's really cool. I'm really looking forward to all of this CAN Bus stuff being EOL in 10-25 years so I can get my hands on it at tinker with it.
  - chiph 9y ago
    There are used beds that use the bus available on eBay and other auction sites. Be aware that it's only on their high-end beds, If you're looking to bid on one, know that they weigh over 600 lbs and need wide doorways (ask me how I know..) Current prices are $900 and up, and often don't come with the inflatable mattresses (hospital may not want the potential biohazard liability, so disposes of it first).
    - Declanomous 9y ago
      Thanks for the tips. I would almost definitely just stash it in my garage while I took it apart. That actually sounds perfect for a project I've been working on. I think changing your environment really helps with thinking, so I added wheels to my desk/workbench at home. I've been trying to find parts that are inexpensive, reliable, and have enough torque to move an entire workbench, but they are near impossible to find. My first goal is to add automated raising and lowering of the table surface so I can switch from sitting to standing. Then I want to replace the casters with actual motorized wheels. The plan is to run the whole thing on a bunch of 18650s and use that as my UPS for the electronics on my workbench as well. Plus I think it would be hilarious to build a desk that you can control from afar, since you have to be at one to use it anyways.
    - King-Aaron 9y ago
      > they weigh over 600 lbs and need wide doorways Spot the Orderly?
      - chiph 9y ago
        We would occasionally get a new model delivered by truck. The one door between the lab and the elevator was a normal (narrow) door. So we'd have to lift the bed onto it's side and maneuver it through. So that's how I know how much they weigh and that they need wide doors. :) The bizarre story was we had an employee that was diabetic, and she passed out one day. When the paramedics arrived, they found her already sitting in a hospital bed.
weberc2 9y ago
Isn't CAN very limited in terms of bandwidth? Seems like this wouldn't be appropriate for most applications of interest? When I worked at an equipment manufacturer, everyone was very concerned about accidentally saturating the bus, and we even had a very compact data representation.
- sokoloff 9y ago
  500kbps is typical. That's not super-slow, IMO.
  - spatulon 9y ago
    It can also operate at 1Mbps. There's a relatively recent extension called CAN FD that can go faster, as can the FlexRay protocol, which is sometimes used instead of CAN.
- spotman 9y ago
  Some systems do up to 1mbps. MIDI for example is nowhere near this. It's not the right protocol for media or bandwidth intensive applications but for control systems or reading sensors its often enough.
  - AceJohnny2 9y ago
    > but for control systems or reading sensors its often enough. But not for the self-driving car generation, where the sensors are higher-bandwidth. As I recall, Mobileye worked around this by just putting the detection intelligence with the camera and sending back synthetic data.
- diydsp 9y ago
  Next stop after can/flexray is EtherCat!
- Mtntk 9y ago
  It varies with length of the connection, if it's short fire it up to 1 mbps or higher. Your speed gets lower as distance gets further

chiph 9y ago

At a previous job I interfaced with hospital beds that used CAN Bus internally. Turns out that Ford had laid off a lot of engineers a few years ago and the firm hired some of them to design the next generation bed. They knew CAN Bus, so they used it to control the hydraulics, pneumatics, lift motors, strain gauges, and so on.

Declanomous 9y ago
Man, that's really cool. I'm really looking forward to all of this CAN Bus stuff being EOL in 10-25 years so I can get my hands on it at tinker with it.
- chiph 9y ago
  There are used beds that use the bus available on eBay and other auction sites. Be aware that it's only on their high-end beds, If you're looking to bid on one, know that they weigh over 600 lbs and need wide doorways (ask me how I know..) Current prices are $900 and up, and often don't come with the inflatable mattresses (hospital may not want the potential biohazard liability, so disposes of it first).
  - Declanomous 9y ago
    Thanks for the tips. I would almost definitely just stash it in my garage while I took it apart. That actually sounds perfect for a project I've been working on. I think changing your environment really helps with thinking, so I added wheels to my desk/workbench at home. I've been trying to find parts that are inexpensive, reliable, and have enough torque to move an entire workbench, but they are near impossible to find. My first goal is to add automated raising and lowering of the table surface so I can switch from sitting to standing. Then I want to replace the casters with actual motorized wheels. The plan is to run the whole thing on a bunch of 18650s and use that as my UPS for the electronics on my workbench as well. Plus I think it would be hilarious to build a desk that you can control from afar, since you have to be at one to use it anyways.
  - King-Aaron 9y ago
    > they weigh over 600 lbs and need wide doorways Spot the Orderly?
    - chiph 9y ago
      We would occasionally get a new model delivered by truck. The one door between the lab and the elevator was a normal (narrow) door. So we'd have to lift the bed onto it's side and maneuver it through. So that's how I know how much they weigh and that they need wide doors. :) The bizarre story was we had an employee that was diabetic, and she passed out one day. When the paramedics arrived, they found her already sitting in a hospital bed.

weberc2 9y ago

Isn't CAN very limited in terms of bandwidth? Seems like this wouldn't be appropriate for most applications of interest? When I worked at an equipment manufacturer, everyone was very concerned about accidentally saturating the bus, and we even had a very compact data representation.

sokoloff 9y ago
500kbps is typical. That's not super-slow, IMO.
- spatulon 9y ago
  It can also operate at 1Mbps. There's a relatively recent extension called CAN FD that can go faster, as can the FlexRay protocol, which is sometimes used instead of CAN.
spotman 9y ago
Some systems do up to 1mbps. MIDI for example is nowhere near this. It's not the right protocol for media or bandwidth intensive applications but for control systems or reading sensors its often enough.
- AceJohnny2 9y ago
  > but for control systems or reading sensors its often enough. But not for the self-driving car generation, where the sensors are higher-bandwidth. As I recall, Mobileye worked around this by just putting the detection intelligence with the camera and sending back synthetic data.
diydsp 9y ago
Next stop after can/flexray is EtherCat!
Mtntk 9y ago
It varies with length of the connection, if it's short fire it up to 1 mbps or higher. Your speed gets lower as distance gets further