Search found 190 matches

by MarkR
Tue Jun 11, 2019 7:11 pm
Forum: Antweights
Topic: Peter Wallers Robot Ramblings
Replies: 739
Views: 99523

Re: Peter Wallers Robot Ramblings

Looks good, nice big rings around those through-hole pins, much bigger than the ones on the RX.

What design software did you use?

I am assuming it's a single-sided layout, IC3 and IC4 are the rz7899 ? I see the pads connect 5-6 and 7-8

Mark
by MarkR
Sun Jun 09, 2019 6:44 pm
Forum: Antweights
Topic: Team Pompidou First Antweight Build/Questions
Replies: 25
Views: 1616

Re: Team Pompidou First Antweight Build/Questions

Difficult to tell. Do you have a multimeter? If so, set it to resistance and measure the resistance of everything (powered off!) which should have resistance, check for short circuits. A N20 motor should have (idle / stalled) resistance of 6-20 Ohms (mine generally read about 12), if it is much less...
by MarkR
Fri Jun 07, 2019 2:54 pm
Forum: Antweights
Topic: Peter Wallers Robot Ramblings
Replies: 739
Views: 99523

Re: Peter Wallers Robot Ramblings

I'm using the rz7899 in the Malenki ESC. It's a single channel H-bridge in a soic8, I don't find them to be difficult to solder unless the board has too much copper around (particularly the 2 ounce copper). The nice thing about it is that it has a good wide voltage range, quite big claims of max cur...
by MarkR
Thu May 30, 2019 9:49 pm
Forum: Antweights
Topic: Team Pompidou First Antweight Build/Questions
Replies: 25
Views: 1616

Re: Team Pompidou First Antweight Build/Questions

The leads from the RX to Dasmikro are Servo leads, they're designed for servos, so they have power. In the case of the Dasmikro, power is fed back from its regulator (aka BEC) to the receiver. So only one set needs to be connected, they're internally connected together in the RX anyway. The 2nd chan...
by MarkR
Thu May 30, 2019 1:38 pm
Forum: Antweights
Topic: Team Pompidou First Antweight Build/Questions
Replies: 25
Views: 1616

Re: Team Pompidou First Antweight Build/Questions

You don't need to connect more than one power / gnd wire from the rx to the Dasmikro. So those extra wires can be cut off. Yes the soldering is a mess, and is likely to fail unless you tidy it up a bit. Check that you don't have any shorts. Maybe a bit of hot glue wouldn't go amiss, the Dasmikro pad...
by MarkR
Fri May 17, 2019 4:53 pm
Forum: Antweights
Topic: Malenki-ESC open source Antweight ESC
Replies: 18
Views: 876

Re: Malenki-ESC open source Antweight ESC

http://vectrex.org.uk/mark/malenki-kicad.png http://vectrex.org.uk/mark/malenki-irl.jpg Parts are here, I have made a couple of the boards so far. It all seems to approximately work, the firmware at least drives my test robot around. If anyone wants one, please PM me, I can make up about 9ish board...
by MarkR
Wed May 08, 2019 10:09 am
Forum: Antweights
Topic: Follow up on Digital CR Servo Board ESCs
Replies: 13
Views: 426

Re: Follow up on Digital CR Servo Board ESCs

All the dead-band logic is inside the MCU, so good luck tuning it. These tiny little MCUs have their own free-running oscillator which goes at whatever speed it feels like. So the MCU might be nominally clocked at 1 Mhz, but in practice it's 1 Mhz +- 10% or maybe worse than that. So the firmware mig...
by MarkR
Wed May 08, 2019 9:01 am
Forum: Antweights
Topic: Follow up on Digital CR Servo Board ESCs
Replies: 13
Views: 426

Re: Follow up on Digital CR Servo Board ESCs

Good detective work. The AM1096 is a very interesting chip because it's a motor driver with built-in voltage regulator, so it saves them components on the board, the LDO voltage regulator presumably supplies the microcontroller, which makes it a "true" 2-chip solution which can handle a wide range o...
by MarkR
Tue May 07, 2019 4:08 pm
Forum: Antweights
Topic: Follow up on Digital CR Servo Board ESCs
Replies: 13
Views: 426

Re: Follow up on Digital CR Servo Board ESCs

Ok, I didn't realise there were two chips. Probably one is a cheapo no-info Chinese Microcontroller, the other is a motor driver, similar to the MX612. Actually the MX612 has pins 5,8 connected to the motor. Don't run it off more than 10V, it's outside of its spec. I actually bought some MX612s, but...
by MarkR
Tue May 07, 2019 2:57 pm
Forum: Antweights
Topic: Follow up on Digital CR Servo Board ESCs
Replies: 13
Views: 426

Re: Follow up on Digital CR Servo Board ESCs

That is very interesting.

Did you, by any chance, get a part number from the 8-pin chip on the blue ESC board above? The Dorman servo board? Is that the only active part on the board, or is there a small transistor too?

Mark
by MarkR
Thu May 02, 2019 12:19 pm
Forum: Questions (and answers)
Topic: 5V bec?
Replies: 6
Views: 234

Re: 5V bec?

Don't most speed controllers have one built-in?

I know the Dasmikro has one, also some brushless esc.
by MarkR
Wed May 01, 2019 3:17 pm
Forum: Antweights
Topic: Tiny 6mm gear motors appearing in Aliexpress
Replies: 2
Views: 168

Tiny 6mm gear motors appearing in Aliexpress

Hi, Has anyone tried these motors? https://www.aliexpress.com/wholesale?catId=0&initiative_id=AS_20190501071600&SearchText=gear+motor+6mm They are getting quite cheap and super, super tiny, maybe good for fleaweights or antweight? Would the (plastic) gearbox destroy itself instantly if we put 8v thr...
by MarkR
Fri Apr 26, 2019 9:01 am
Forum: Antweights
Topic: The Hotel Lima, for Ants: A Build Diary
Replies: 93
Views: 3874

Re: A Hotel, constructed of Limas, for Ants: A Build Diary

It's easy to preach after the fact... I usually test my electronics with a multimeter (for short circuit) bench supply (for functionality) before plugging a lipo in. The Lipos give enough current to pop the magic smoke out of any faulty electronics. That said, I've never had the lipo itself catch fi...
by MarkR
Mon Apr 15, 2019 8:00 am
Forum: Questions (and answers)
Topic: Small ESCs outside the UK
Replies: 13
Views: 622

Re: Small ESCs outside the UK

George- I will try enabling braking to see what happens. I didn't realise that braking was a useful feature, I didn't use braking on my previous robot (Betsie, which has a sort of fly-by-wire system anyway) and I've not implemented braking yet in the new speed controller (but the hardware is capable)
by MarkR
Mon Apr 15, 2019 7:53 am
Forum: Antweights
Topic: Pre modded servo boards for escs?
Replies: 30
Views: 1250

Re: Pre modded servo boards for escs?

Sounds more like a poor design or poor choices of parts, than a manufacturing defect. A voltage drop of 2V at the kind of current we'd see through a N20 is extremely high, did you have access to an oscilloscope? Maybe the duty cycle is less than 100% even when the stick is at the extreme position? -...