{"id":4581,"date":"2016-02-27T07:08:28","date_gmt":"2016-02-27T12:08:28","guid":{"rendered":"http:\/\/www.plastibots.com\/?p=4581"},"modified":"2019-12-29T16:46:21","modified_gmt":"2019-12-29T21:46:21","slug":"lulzbot-mini-arduino-temp-monitor-fan-led-controller","status":"publish","type":"post","link":"https:\/\/www.plastibots.com\/index.php\/2016\/02\/27\/lulzbot-mini-arduino-temp-monitor-fan-led-controller\/","title":{"rendered":"LulzBot Mini: Arduino Temp Monitor \/ Fan & LED Controller"},"content":{"rendered":"

\"\"<\/a>I’m on a mission to reduce the amount of noise my LulzBot Mini 3D printer makes.
\nI’ve already added a motor damper to the Y axis. \u00a0However, one thing that is consistently noisy is the case fan. \u00a0 It’s on at > 70% nearly all the time. \u00a0In addition to this, the air vent fins in the side of the case amplifies the fan noise. \u00a0So, I decided to build my own fan controller. \u00a0 Killing 2 birds with one stone, I also wanted to merge my LED light controller<\/a> into this project.
\n<\/p>\n

What does it do?\"Capture\"<\/a><\/strong><\/p>\n

Pretty straight forward. \u00a0An Arduino Nano is at the heart of it. \u00a0It monitors 2 temperature sensors mounted in areas that get hot. \u00a0Before selecting the locations, I ran a test print and used my laser temperature gun on the main board to see what areas got hot. \u00a0As expected, the 4 motor driver chips on the RAMBO boards were it. \u00a0They ranged from 30 C (idle) to 85C (printing). \u00a0As the X & Y axis get the most action, I mounted a sensor directly to one of those chips. \u00a0 The other was mounted to the power supply, but this does not get very warm. When the printer is turned on, the Arduino\u00a0controller idles the fan at about 650 RPM. \u00a0It never turns off. \u00a0At this level, you can’t even tell it’s on. \u00a0When printing starts, the Arduino polls the sensors every second and adjusts the fan speed based on the stepper motor controller chip temperature. \u00a0The sensor returns Celcius values. \u00a0Temp ranges (30-90C) are mapped to the AnalogWrite function to control the fan speed from idle (~650RPM) to full \u00a0(~2200 RPM).<\/p>\n

I also merged LED control into this project. \u00a0It has a push-button on top. \u00a0Using an interrupt, it allows switching between high, medium and low light levels. \u00a0 \u00a0The display is there for s*its and giggles really.. \u00a0I had some laying around and thought it would be cool to provide some visuals. \u00a0That way I would have something else to do for those times when I find myself staring at a print job for prolonged periods of time. \u00a0 \u00a0The display shows the RAMBO and power supply “SUPL” temps, the LED level, an animated fan icon, the fan RPM and voltage being applied to the fan. \u00a0The Mini stock fans are 24V, but for this project I dropped everything to 12V.. The\u00a0project, LEDs and fan are all powered by a switching regulator that takes 24V from the internal power supply and drops it to 12V.<\/p>\n

It’s also important to note that this project is not specific to any one device. \u00a0It is completely standalone. \u00a0Simply supply 12V and mount\/glue the temperature sensors wherever necessary.<\/p>\n

<\/a><\/center><\/p>\n

How well does it work?<\/strong><\/p>\n

\"IMG_1093\"<\/a>I’ve mounted the temperature sensors, the fan, connected power and have started further testing. \u00a0Overall, I’m very happy with the result. \u00a0The fan is quiet now and idles at about 600 RPM. \u00a0Once the printer starts and the driver chips begin heating up, it ramps up to 1200 RPM. \u00a0Even at this speed the fan is barely noticeable. \u00a0The hum of the steppers stands out more now. \u00a0Before I mounted the temp sensor, I used by laser temperature gun to monitor the status of the motor driver chips both during idle as well as printing. \u00a0Given the X & Y motors do a lot more work, I focused on those 2 chips. \u00a0At idle, they hovered around 30-40C. \u00a0During printing they would heat up between 65-80C. \u00a0 With the case closed, I don’t think they would normally hit 80C. \u00a0This happened because I was mucking around in the case and the stock fan was not able to do its job (too far away with the case open).<\/p>\n

When I mounted the LM35 directly to the chip, the readings were much lower (high 40’s during printing). \u00a0 There could be a number of reasons for this. \u00a0The Noctua could be doing a good job, or there is some loss in thermal conductivity with the glue I used to mount the sensor to the chip (did not use thermal past). \u00a0However, there is only a very thin layer of glue between the two. \u00a0At the moment I’m mitigating this by dropping the maxTemp value so the fan ramps up more quickly. \u00a0I’ve got some tiny heatsinks on order. Once installed, I’ll mount the LM35 to the sink itself and calibrate the temperatures after further testing.<\/p>\n

Update: March 10th:<\/strong><\/p>\n

So, I’ve been printing now for a week or so and have a few observations:<\/p>\n