Industrial Indicator Makes the Move from PLC to FPGA

Industrial controls are fun to use in a build because they’re just so — well, industrial. They’re chunky and built to take a beating, both from the operating environment and the users. They’re often power guzzlers, though, so knowing how to convert an industrial indicator for microcontroller use might be a handy skill to have.

Having decided that an Allen-Bradley cluster indicator worked with the aesthetic of his project, a Halloween prop of some sort, [Glen] set about dissecting the controls. Industrial indicators usually make that a simple task so that they can be configured for different voltages in the field, and it turned out that the easiest approach to replacing the power-hungry incandescent bulbs with LEDs was to build a tiny PCB to fit inside the four-color lens.

The uniquely shaped board ended up being too small for even series resistors for the LEDs, so a separate driver board was also fabbed. The driver board is set up to allow a single 5-volt supply and logic levels of 3.3-volt or 5-volt, making the indicator compatible with just about anything. The finished product lends a suitably sinister look to the prop.

If you’re not familiar with the programmable logic controllers such an indicator would be used with in the field, then maybe you should try running Pong on a PLC for a little background.

In-N-Out Boards Sans Hamburgers

board Before this project, [David]’s office had a fairly terrible system to tell everyone who was in the office, who was out, and who wasn’t coming in today. Velcro and whiteboards will do the job, but arcade buttons and LEDs called to [David], leading him to create this In/Out Status Board.

The old system consisted of a whiteboard on the side of each partition, with velcroed labels indicating if a particular person was in the office today, out, sick, or on holiday. Inconvenient to change, and there was no single place everyone could look to see if a particular person was in or not. The new system consists of a four-person pod with four arcade buttons and WS2811 LEDs, an Arduino Nano, and a 433 MHz radio. The main panel is just a bigger version of the four-person pod, keeping track of everyone in the office.

A single button switch will change a person from being in to being out, with longer presses necessary for ‘sick’ and ‘vacation’. It’s interesting to note what’s not included in this build: A fingerprint scanner was out of the question, because that would effectively eliminate anyone ever being marked as ‘sick’. An RFID tag reader was out for the same reason. Also not included is a display. That’s just fine, really – [David] won’t be changing the labels very often, anyway, and that would just add to the cost and complexity of the project.

Wireless toilet occupancy sensor


It’s a bit awkward for all parties involved if someone is waiting right outside the bathroom door. This system helps to alleviate that issue by letting the next user know when the loo is available. [Akiba] has been working with the folks at Loftworks, a design company in Tokyo, to get the status beacons seen above up and running.

The staff is mostly women and there is just one single stall women’s toilet on each of the three floors. The boxes above represent the three stalls, using colored light to indicate if a bathroom is available or in use. Detection is based on a PIR motion sensor in each stall. They communicate back with the display units wirelessly, which initially presented quite a problem. The doors on the bathroom are steel, and when closed they effectively block communications. The 900 MHz radios used in the system are on the 802.15.4 protocol. But they can be set a couple of different ways by moving resistors. Each came configured for the fasted data throughput, but that’s not really necessary. By changing to a slower configuration [Akiba] was able to fix the communications problems.

We remember seeing a similar bathroom indicator in a links post some time ago.

BlinkM gets upgraded to a USB mass-market device

[TodBot] has a new piece of hardware on the way up. His Blink(1) is currently about 50% funded on Kickstarter. It’s a USB nub that has an RGB LED inside of it. When plugged into a computer it can be used as a status indicator. At first that sounds like a let down, but his marketing is fantastic as the myriad of uses really caught our attention. If you’re on the road you can use it to report back your server statistic. Plug one into each rack-mounted servers for quick visual indication of which one has crashed. Or find your own use.

You probably remember [TodBot] as the creator of the BlinkM. Recently he was calling it the world’s smallest Arduino. Well this Blink(1) is being marketed as Arduino programmable as well. The board size is about the same, and both have an RGB LED module. The difference is that the BlinkM had an ATtiny85 and needed a serial converter to program it. This has a USB plug so we’d bet he’s swapped the tiny for an ATmega8u2 or something from the same family.

Don’t think one blinky LED is going to cut it? For folks that just need more resolution there are other hardware options out there. For instance, this project gives you a wireless 8×8 RGB led display to use as an indicator.

Gear indicator for Suzuki motorcycle

This little board serves as a current gear indicator for a motorcycle. It was designed with the Suzuki V-Storm motorcycles in mind as they have a sensor built into the gearbox. Other gear indicators rely on sensors on the shifters themselves, but reading the voltage level from a gearbox sensor gives much more reliable information.

The voltage measurement is handled by an ATmega88 microcontroller which in turn drives the 8×8 LED display. Also built into the system is a temperature sensor and photoresistor. The firmware takes advantage of both of these inputs, displaying temperature when in sixth gear or at the push of a button, and dimming the display based on ambient light. There are also settings for screen rotation, and user preferences.

We didn’t find schematics or software but this should be pretty easy to replicate. If you need a primer for AVR programming we’ve got you covered.

[Thanks Michal]

The Spindicator

oooh shiny

[Harvey] wrote in to share the Spindicator with us. The spindicator is a hard drive activity activity indicator built in a ring to resemble a dekatron. Using the pulses from the hard drive activity LED, [Harvey] tested several different methods of interpreting that data for display. The final version, negative edge triggered with a lowpass filter can be seen after the break.  It is nice and smooth and vaguely reminiscent of many programs’ loading screens.

He has pictures and tons of detail on the project including videos of previous versions that acted quite erratically.

Continue reading “The Spindicator”

Motorcycle current gear indicator

[Vassilis Papanikolaou] just finished building a gear indicator for a motorcycle. This quite a simple implementation compared to some of the other vehicle information displays we’ve taken a look at. You should be able to build and install your own without breaking the bank. An ATtiny25 microcontroller reads data from a couple of hall effect sensors and the neutral switch, then displays the current gear on a 7-segment display.

There’s a magnet on the shifter and two hall effect sensors at the position for ‘gear up’ and ‘gear down’ shifting. The AVR chip keeps track of these and even stores the last position in EEPROM when you shut the bike off. If the device somehow gets off track, it will automatically recalibrate itself next time you shift into neutral, thanks to the bike’s neutral sensor switch.