M.L. Toys
M.L. Toys
HobbyMasters M.L. Toys
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By 87jeepwrangler
with my racing season in full swing (doing VERY well so far this year) i've had zero time to work on my stroller project (viewtopic.php?f=19&t=5027), so i needed something my little guy could ride around on until i get that done. a friend gave me a lil' quad which he's been LOVING, but since he's only 9 months old, i have to do the throttle and steering while he sits on it. i'm already tired of walking around the yard hunched over, so i decided to do a quicky RC mod to the lil quad. the plan is to do it in 2 stages, the first adding RC throttle control, and the 2nd adding steering. i'm not going all out on this one like i'm doing with the stroller project, i just need something to work quickly. on to the pics...

the quad leaned when i got it. after looking into it, the plastic was badly deformed. probably overloaded at some point.
lilquad(00).JPG (122.43 KiB) Viewed 2684 times
nothing a little metal work wouldn't fix...
lilquad (01).JPG
lilquad (01).JPG (141.68 KiB) Viewed 2684 times
lilquad (02).JPG
lilquad (02).JPG (138.33 KiB) Viewed 2684 times
all better
lilquad (03).JPG
lilquad (03).JPG (107.73 KiB) Viewed 2684 times
lilquad (04).JPG
lilquad (04).JPG (92.74 KiB) Viewed 2684 times
before messing with the wiring, i wanted to know what kind of amps i was up against. i used a clamp on amp meter to find out the peak inrush of amperage when the motor was bogged down hard. the highest reading i could get was 10.5 amps at 6 volts.
lilquad (05).jpeg
lilquad (05).jpeg (117.58 KiB) Viewed 2684 times

User avatar
By 87jeepwrangler
the stock lil' quad has only a on/off button, and forward only. i wanted both forward and reverse, and needed a simple way to control that. knowing the motor shouldn't draw more than about 10 amps, i used a common 12v 20amp DPDT momentary center-off switch, and a servo to control it.
lilquad (06).jpeg
lilquad (06).jpeg (133.66 KiB) Viewed 2680 times
lilquad (07).jpeg
lilquad (07).jpeg (134.4 KiB) Viewed 2680 times
some wiring pics
lilquad (08).jpeg
lilquad (08).jpeg (110.64 KiB) Viewed 2680 times
lilquad (09).jpeg
lilquad (09).jpeg (114.79 KiB) Viewed 2680 times
temporarily mounted. i need to go back and clean up the wires and permanently mount everything now that it's working.
lilquad (10).jpeg
lilquad (10).jpeg (128.89 KiB) Viewed 2680 times
lilquad (11).jpeg
lilquad (11).jpeg (121.21 KiB) Viewed 2680 times
User avatar
By Jornum1
Nice Rob!
You are like me about a year ago! Your starting him out even earlier then I did!
I was in the same boat when my son had the brute force. I was following him around with a broom stick to push the pedal! I finally gave up and thats what started all the RC stuff.
User avatar
By 87jeepwrangler
got the steering done today. my rc crawler donated one of it's 1/4 scale servos :cry: so i'll have to replace it with a new one. since the lil quad is so light and small, the servo has no problems turning the wheels even when stopped on grass. to give it as much mechanical advantage as i could, i made sure the throws worked such that the servo is programmed to turn almost 150% of it's normal operating range to turn the wheels lock to lock.

1/4 scale servo and servo mount
1.jpeg (109.34 KiB) Viewed 2659 times
ruler for size reference. the 1/4 scale servos are BIG.
2.jpeg (115.3 KiB) Viewed 2659 times
mounting bracket i made for the tie rod. screws weren't tightened yet.
3.jpeg (99.16 KiB) Viewed 2659 times
the drag link which connects the steering servo horn to the tie rod.
4.jpeg (142.04 KiB) Viewed 2659 times
finished assembly.
5.jpeg (81.19 KiB) Viewed 2659 times
6.jpeg (108.19 KiB) Viewed 2659 times
User avatar
By Jornum1
Nice little project! I bet your son loves it.

I really didnt have too much of a issue with my brute force steering it with the servo gearbox.
The problem came when my son got strong enough to fight the servo from the handle bars! I ended up having to make a system to disengage the handle bars.

Just a fyi, I know he is still young, but it will be strong enough sooner then you think!
User avatar
By 87jeepwrangler
update: the original battery it came with finally gave up, so i put in a new larger 6v and wired in an inline fuse right after the + side of the battery.

weather pack ATO fuse holder mounted:
photo 4.JPG
photo 4.JPG (80.03 KiB) Viewed 2545 times
the new battery is physically larger, so it needed a hold-down redesign. here's the lower hold down:
photo 5.JPG
photo 5.JPG (107.46 KiB) Viewed 2545 times
upper hold down:
photo 3.JPG
photo 3.JPG (105.08 KiB) Viewed 2545 times
photo 2.JPG
photo 2.JPG (111.91 KiB) Viewed 2545 times
new battery harness:
photo 1.JPG
photo 1.JPG (96.89 KiB) Viewed 2545 times
photo 6.JPG
photo 6.JPG (130.45 KiB) Viewed 2545 times
User avatar
By bruces_eviltwin
nice work! thanks for the quality of your details in this thread
I can tell what you did, but I can’t tell what parts you used. Could give me an exact parts you used for your modifications? The only part that I can make out from the pictures is the servo, which is HS-485HB. What are you using to control the servos? Thanks in advance.

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