GPS for eachine 250
« on: February 16, 2016, 04:25:20 am »
Anyone found a GPS to plug into the eachines yet?


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    • LibrePilot
Re: GPS for eachine 250
« Reply #1 on: February 16, 2016, 09:21:29 am »
Hi w7atr, welcome

You can setup a GPS with CC3D for telemetry/OSD use, but not for autonomous flight.
Every Ublox GPS works but need flash memory to store config because CC3D do not support autoconfig feature.


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Re: GPS for eachine 250
« Reply #2 on: February 27, 2016, 07:50:30 am »
My brother is setting up a Mini Revolution package, from Banggood, on his Eachine 250 racer. It is going well so far. The Eachine comes with a, second, longer JST-SH cable that plugs directly into the Mini Revolution and the PCB. No soldering needed at all. So all of the OSD info should work still. The PWM "in" connector is the same as the original CC3D board. It is almost a direct swap for the CC3D!

He had to 3D print a plate. (it was for a CC3D Atom board, he flipped it over) to mount the FC into place. A flat plate with 30.5mm center to center hole would work too. Very small GPS unit. Came with Oplink minis that can be added for telemetry. He has gone through setup and had everything working and spinning. Unfortunately he was using OpenPilot, not LibrePilot. When he found that the map there would not work, he then remembered I told him to use LibrePilot! LOL. So he got to go through it all twice!

One problem he had; The Cables from the Eachine PCB to the CC3D did not seem to fit. He took the case off then it fit just fine. The port through the case is on the small size. He left the cable plugged in and closed the case up again. The JST-SH connectors have ears that stick out. So either open up the port in the case or do it like he did.

On my RCTimer Indy 250 plus, the difference in stabilization was night and day different when I switched from a CC3D to a Revolution Board.
Turnigy Talon Carbon Fiber V1
Generic 2212 motors 1000kv
1045 props
Revolution (BG)


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Re: GPS for eachine 250
« Reply #3 on: May 24, 2016, 01:54:34 pm »

sorry but i try to do the same as your brother with upgrading an eachine racer 250 to revo mini. But i have a problem with the RC input voltage that goes down to 1,3 V when i plug the receiver. Does it "talk" to you ?

Thank you


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    • LibrePilot
Re: GPS for eachine 250
« Reply #4 on: May 24, 2016, 09:21:39 pm »
Maybe the wiring is not the same for original Eachine CC3D and Revo Mini.

Compare wiring to the right

Re: GPS for eachine 250
« Reply #5 on: May 28, 2016, 05:44:17 pm »
Here is also wiring of the Input port, which I reverse engineered myself for connecting minimOSD from that Banggood Revo package:

1. GND
2. VCC_UNREG (+5V in my case on Racer 250)
3. PWM1 (PB14)
4. PWM2 (PB15)
5. PWM3 (PC6, Telemetry/OSD TX)
6. PWM4 (PC7, Telemetry/OSD RX)
7. PWM5 (PC8, OSD DTE)
8. PWM6 (PC9)

I.e. the match between 8-pin connector on Banggood Revo and 10-pin on original Revo is:

BG -- Orig
 1 -- 1
 2 -- 2
 3 -- 5
 4 -- 6
 5 -- 7
 6 -- 8
 7 -- 9
 8 -- 10
« Last Edit: May 28, 2016, 06:31:42 pm by tchicago »

Re: GPS for eachine 250
« Reply #6 on: May 28, 2016, 06:07:06 pm »
I've tried using the GPS from Banggood package on Racer 250 and it kind of works. But there are issues.

First I have a warning. Actually like this !WARNING!
The VCC(+5 or more) and RX on GPS lines were crossed on Banggood GPS: RX(orange) and 5V(red). So it did not work out of box at all. I had to take the GPS out of that plastic box, completely destroying the box, only to find out that those two wires were miswired. After fixing it and wrapping GPS into thermoshrink tube, the GPS worked fine. A lot of people on Banggood complain that the GPS does not work and overheats, and this is the exact symptom you should get if you connect the mis-wired RX line to something like +12 volts unregulated that this GPS claims to support.

By the way, you first have to connect it to the FTDI or other serial port dongle in order to configure the proper Ubx output message types, just as described in the Librepilot doc. The GPS board has a backup battery for keeping the config and timebase, so the GPS is pretty good.

However, still I found it pretty much useless on Racer 250 with Librepilot. Using GPS with Librepilot requires to use the magnetometer, and the built-in magnetometer on that Revo board is useless as it picks up magnetic noise from the motor wires and Racer's PDB. The heli ends up flying sideways and straight into the ground. So you really need an external magnetometer mounted high on the mast, away from Racer's magnetic fields.

The next version of LP (is it 16.06?) should support external magnetometer in combination with external GPS. So I'm planning to get one of those Naza-protocol serial GPS/Compass and try it again. There are many clones of this unit - Google "Naza GPS", or search for it on eBay. There are combos that include a sturdy mast.