Makita lawnmower forcing high-speed mode - Page 1
Forum section: electronics / beginners

author: Rudager
author_rank: Newbie
timestamp: July 16, 2022, 02:51:55 pm
content: Hello,I'm new to electronics. I purchased a Makita lawnmower DLM530. There is a quiet mode and a high-speed mode. The quiet mode is the default. I want to force the high-speed mode for collecting lawn debris in the autumn. I can't figure out if the high speed mode is triggered by current-draw or RPM sensing. There are hall effect sensors and I have provided a waveform for them. The electronics are all potted in resin so I can't test for many things. I don't want to burden the motor just to encourage the high-speed mode. I was playing with the idea of intercepting the hall effect sensors with an arduino and delaying the signal to trigger the high-speed mode.Any help would be appreciated.

author: Rudager
author_rank: Newbie
timestamp: July 16, 2022, 02:53:52 pm
content: I would provide photos but EEVblog is preventing me.

author: Rudager
author_rank: Newbie
timestamp: July 16, 2022, 02:56:08 pm
content: More photos

author: Kleinstein
author_rank: Super Contributor
timestamp: July 16, 2022, 03:06:36 pm
content: This looks like a brushless motor and this would also make sense. In this case it would be hard to directly manipulate something at the motor control. The way to force it into the high speed mode would be more to control the user interface. So act as if the user chooses the higher speed.

author: Rudager
author_rank: Newbie
timestamp: July 16, 2022, 03:12:06 pm
content: There is no high-speed mode on the user-interface. There is an "power" button and a button that forces the "quiet mode". That is all.

author: BeBuLamar
author_rank: Super Contributor
timestamp: July 16, 2022, 04:04:05 pm
content: So when would the mower go into high speed mode?

author: Grandchuck
author_rank: Super Contributor
timestamp: July 16, 2022, 04:06:16 pm
content: As a guess, current is low when quiet mode is enabled and when current is high it enables high speed. Find the current sensor and experiment?

author: Rudager
author_rank: Newbie
timestamp: July 16, 2022, 06:18:52 pm
content: It's automatic. When you encounter thicker grass, it boosts the motor rpm from 2400rpm to 2800rpm. There is a delay after it is activated before it slows back down. It's not infinitely variable though, two distinct modes - high and low.

author: Rudager
author_rank: Newbie
timestamp: July 16, 2022, 06:31:53 pm
content: There is a loop of wire that protrudes from the epoxied brain-box. I have a AC/DC current clamp meter. Do you think that could be a current sensing shunt?If so, how would one fool the ESC to sense more current? I would hate to just throw a massive resistor in there an call it a day. It is a battery-powered mower after all.

author: Rudager
author_rank: Newbie
timestamp: July 16, 2022, 10:11:03 pm
content: The quiet mode button is just a soft button. It just tells to mower to not go into high speed mode. So you don't disturb your neighbours. Quiet mode/low RPM mode is the default.See the video at the 4:30 mark:

author: Siwastaja
author_rank: Super Contributor
timestamp: July 17, 2022, 12:29:50 pm
content: I don't think there is an easy way.Current sense is definitely on the board, potted away. Messing with it would be difficult, anyway.The selection algorithm is probably on the same microcontroller as the actual motor control.

author: David_AVD
author_rank: Super Contributor
timestamp: July 17, 2022, 09:30:11 pm
content: I have the same (or similar) model mower and would also like to be able to lock it into high speed mode. I think the brand new models do have this as an option.

author: electromateria
author_rank: Regular Contributor
timestamp: July 18, 2022, 01:58:54 am
content: You could always buy an ESC and wire it up, it's not overly complex even for a beginner. Fun skill to learn IMO.I'm a beginner myself so this maybe a bad suggestion but *if it's a brushed motor* you could just send the rated voltage right to the motor and delete the ESC. Get a dirt cheap digital volt meter to prevent over discharge of batteries. For charging, not sure what your setup is like or if it runs through ESC but more mods might be needed.If quiet mode is based on detection might as well just leave it, (it activates automagically when needed).. unless you're super motivated to mod it.

author: Rudager
author_rank: Newbie
timestamp: July 18, 2022, 12:41:34 pm
content: I think this will be the way I need to do it. But at least I would have full control and be able to select any speed I want!

author: sairfan1
author_rank: Frequent Contributor
timestamp: July 18, 2022, 04:42:00 pm
content: No matter what if its a DC brushed motor, or brush less, see if you find replacing cheap motor driver on aliexpress and replace the driver, now you can freely play with it to further customize it.