Sub250g Thermal Imaging Quad - Apex3IR

We have developed a compact thermal imaging solution for FPV drones. To prove the compactness, the goal was to realize a quad with less than 250g.

Our highlights:

• Picture in Picture Thermal and Visible Image
• Robust 1-axis gimbal based on the included servo
• 247.9g with 3S 1100mAh LIPO Battery
• 8min flight time
• INAV Position Hold
• Buzzer

Impressions:

In this post you can find out how we managed to do this and how you can do it too. You can find a parts list at the end of this post.

As a basis the frame Micro Apex 3" Frame Kit is used. To fit M2 stack screws for a 20x20 AIO washers are used as it can be seen on the following pictures. The screws are tightened with a M2 nut.

Use racewires to protect the motor cables from the propellers. This also makes it easier to replace the motors. You can file them so it fits for this frame. To save weight titan screws are used. The servo is glued to the side plate. Use glue like E8000, this one will not get completely hard. The brushless motors on the pictures are not the final ones. Instead RCINPOWER SmooX 1404 Plus 3850KV are used. A VTX, buzzer and ELRS receiver are installed. The VTX is installed at the front so that the GPS is less disturbed.

As FC the All in One Flight Controller GHF420AIO is used. There is an INAV target for this and it fits perfectly into the frame. Additional to the standard devices the 7pin cable to the IR-CAM Base is soldered for power supply, analog video and MSP communication. Foam is used to protect the barometer from the wind. In order to avoid vibrations on the IMU, there should be no cables lying on it or they should be fixed with a little silicone.

A configuration file for INAV version 7.1.2 is available free to download. Please make sure, the connections are like in the tables:

The cable to the camera module was extended and fixed with double-sided adhesive tape. To protect the contacts, they are encapsulated with flowable silicone. The servo motor is soldered to the intended pads on the IR-CAM Base.

One stand-off can be left out. Anti-slip dots are added at the bottom with the glue for better battery mounting.

Finally we reached a weight of 180.6g without battery. With a 3S battery it’s still beneath 250g. Sufficient for a flight time of up to 8 minutes.

After completing the build several improvements were made which we do not want to withhold from you.

Improvements:

• Better motors - RCINPOWER SmooX 1404 Plus 3850KV
• Use of copper foil for GPS
• GOKU GM10 PRO V3 GPS for better position estimation
• Textile Tape 19mm for Stack protection and wind canceling

Interested? Checkout our other videos on Youtube to get more information about our thermal solution. You can find the necessary 3D printed parts, CLI file and the IR-CAM on our website: https://shop.inel.at/produkt/ir-cam-ntsc-pal/

If you have any questions, please let us know in the comments!

Parts list (Prices inluding 20% VAT):

45,52€ - Frame: Impulse RC Micro Apex 3" (drone-fpv-racer)
5,90€ - Race wires: 4" MICRO APEX RACE WIRE - BLACK (drone-fpv-racer)
66,67€ - AIO: JHEMCU GHF420AIO-BGA (banggood)
955,00€ - IR-CAM (NTSC/PAL) (InEL)
4x17,29€ - Motors: RCINPOWER SmooX 1404 Plus 3850KV (aliexpress)
4,30€ - Props: AVAN MINI 3 INCH PROPELLER 3X2.4X3 (aliexpress)
13,03€ - Battery: GNB 1100mAh 3S 50/100C XT30 (gaoeng)

... Battery Connector: XT30 ...
... Battery Stripe ...

34,90€ - VTX: TBS Unify Pro32 Nano 5G8 (drone-fpv-racer)
19,90€ - ELRS-RX: BETAFPV - ELRS Nano Receiver 2.4G (drone-fpv-racer)
12,90€ - Buzzer with Battery: VIFLY Finder Mini (drone-fpv-racer)

11,90€/20,00€ - VTX Antenna:
for LHCP: Caddx Antenna for Vista - 15cm (drone-fpv-racer)
for RHCP: Lumenier Micro AXII 2 RHCP U.FL Long (getfpv)

Titan M3 and M2 Screws of different lengths (aliexpress):
3,60€ - Frame: 9 Pcs. M2,5 x 8mm [M2.5X8 20PCS]
2,98€ - Arms: 4 Pcs. M3 x 10mm [M3X10 20PCS]
3,15€ - Motors: 8 Pcs. M2 x 6mm [M2X6 (S1.5) 20PCS]
3,01€ - Props: 8 Pcs. M2 x 8mm [M2X8 (S1.5) 20PCS]

0,98€ - Stack: 4 Pcs. [M2 x 50Pieces] + [20mm] (aliexpress)
0,98€ - Nuts M2 for Cam, Servo, Stack (aliexpress)
0,98€ - Washer M2 for Stack Screws (aliexpress)
0,98€ - Textile Tape 19mm for Stack protection and wind canceling aliexpress)
3,77€ - Copper Tape 30mm for GPS sheelding (aliexpress)
0,98€ - E8000 Glue for Battery sticky coating and Servo fixation (aliexpress)
0,98€ - 1,8mm Cable ties for GPS-cover, Antenna fixation, XT30 fixation (aliexpress)
0,98€ - Threadlocker for all screws and nuts (aliexpress)

... Double Sided Tape ...
... Flowable silicone ...
... Polycarbonate for 3D printed parts ...