[mike_waclo]

Looking good! I saw your concern about the voltage, and what I found was that even though it's a 7.2V battery, when I tested the output through the little remote switch connector with a multimeter, I was only getting 6V, so that's why I think with the 4.5V multi-light run in series with the single LED light that usually drew 1.5V, everything's been OK without blowing out the bulbs.

I am no electrician by any means, so I may just be running on luck at this point... Glad I bought a multi-pack of those flashlights!

[Mercifull]

Looking good! I saw your concern about the voltage, and what I found was that even though it's a 7.2V battery, when I tested the output through the little remote switch connector with a multimeter, I was only getting 6V, so that's why I think with the 4.5V multi-light run in series with the single LED light that usually drew 1.5V, everything's been OK without blowing out the bulbs.

I am no electrician by any means, so I may just be running on luck at this point... Glad I bought a multi-pack of those flashlights!

My electronics knowledge is fairly rudimentary but it’s not like we’re going to be running these lights for long periods of time so they’ll probably last forever* even if the voltage isn’t ideal.

*ish.

[Mercifull]

Not much to report today other than I built all new shocks for my RTV.

As standard a vxl 4x4 Stampede comes with two long ultra shocks for the front and two xx-long shocks for the back with white springs. The RTV requires two sets of front/long shocks.

My second hand Stanpede came with anodised blue aluminium shocks, they look nice enough on a truck but completely inappropriate for the RTV.


So I purchased two new sets of long grey/red Traxxas Ultra Shocks TRX3760A.

They do not come assembled to I used this video as a guide which was very helpful. I used a few drops of silicone shock oil on the rods and then filled the cylinder up. Added the cap ends and springs and all sorted. Installed to the front (of the original chassis) as a test and they already look so much better.

[Mercifull]

There’s a roadblock now with regards to my build. Well… sort of.

I ordered a nylon sls printed chassis in black from pcbway on recommendation by Ben Eadie (prob master in Afterlife) which was significantly cheaper than doing it locally. However… I just realised it’s not even being made until June and the it’ll take at least a couple of weeks to ship. Whoops.

I might do some testing of layouts with my fdm printed chassis in the meantime though and it also gives me time to also experiment with an arduino for doors, bargraph and red light.

[Mercifull]

I did some test fitting of the Traxxas components in the fdm printed chassis and am struggling with getting the front and end pieces on with the drive shaft. I was under the impression the drive shaft needed cutting to 107mm but this feels at least half a cm too long to me as I can’t get the front to line up with the holes.

[mike_waclo]

I did some test fitting of the Traxxas components in the fdm printed chassis and am struggling with getting the front and end pieces on with the drive shaft. I was under the impression the drive shaft needed cutting to 107mm but this feels at least half a cm too long to me as I can’t get the front to line up with the holes.

I definitely had to do my own measurement for the drive shaft as well. Mounted everything else on the frame, and then held the driveshaft in place and marked where it lined up with the end that needed cut.

[Mercifull]

I definitely had to do my own measurement for the drive shaft as well. Mounted everything else on the frame, and then held the driveshaft in place and marked where it lined up with the end that needed cut.

Out of curiosity do you recall what your length was? I'm reluctant now to cut it further until my nylon chassis arrives just incase it's a mm different or something weird.

[mike_waclo]

Out of curiosity do you recall what your length was? I'm reluctant now to cut it further until my nylon chassis arrives just incase it's a mm different or something weird.

Well, I did the v1 version of the chassis and print files, so mine’s going to end up being a bit longer, because you said you were doing the v2, correct?

[Mercifull]

Out of curiosity do you recall what your length was? I'm reluctant now to cut it further until my nylon chassis arrives just incase it's a mm different or something weird.

Well, I did the v1 version of the chassis and print files, so mine’s going to end up being a bit longer, because you said you were doing the v2, correct?

Yeah you're right, I'm using Taco belli's V2. Maybe I'm best just waiting for the nylon chassis and then making my own decision. At least I didn't cut it too short and have to buy another drive shaft.

[Mercifull]

Some good news today, looks like pcbway are making my chassis right now. Completion estimate is by 11th although it’ll be a few weeks probably until it actually arrives at my doorstep.


Some bad news as well though. The little connector I ordered from aliexpress appears to have lost its label. Tracking shows it going to the wrong hub a few times and now it’s showing as returning to sender. It’s a shame that I can’t contact Royal Mail and identify myself as the correct recipient. Now I’ll need to wait for it to be returned before it can be resent or refunded. Urghhh.

[tobycj]

Sleaford is 5 minutes from me!

[Mercifull]

Sleaford is 5 minutes from me!

Its more than 200miles from me! Who knows where it is now. Probably on its way back to China. Ridiculous. It's an item that cost £5 including shipping. How much waste and resources and carbon footprint because they couldn't just contact me about it. They clearly have a tracking number as they have been updating it, I also have a tracking number. All thats missing is possibly a malformed address on the label which could have been resolved had contact been made.

[tobycj]

Very annoying. I've got an Etsy order to the US that made it to New York, then suddenly went to Riyadh in Saudi Arabia! No idea what the hell is going on with it, so waiting for the tracking to update and see what happens next. Good old mail services!

[Mercifull]

I am struggling to detect the position of the 3 way toggle switch on the top of my TQi transmitter with an Arduino. If I use one of those rc relay on/off adapters it easily detects if the toggle is on/off and sends power (or not) to whatever circuit Ive connected. I thought I could just connect straight from the receiver to a pin on the Arduino and read it somehow but I just cant work it out. Does anyone have any ideas or a working sketch?

[Mercifull]

I tried about a dozen different code snippets and chatgpt scripts but none worked. Turns out its simply because I didn't use a common ground. So now I have on Channel 4 just the Signal pin on a jumper from the RX to Pin 8, and then I have a Signal and Ground on Channel 5 connected to Pin 9 and GND respectively. Its currently still being powered by the USB although I will eventually take a feed off the BEC and step down the 6v to 5v so I can cleanly power the Arduino too.

The Traxxas TQi 6530 Transmitter (far right in image) has two additional switches compared to the regular TQi (left) although the top toggle actually shares Channel 4 and 5.

The red thumb toggle is Channel 3 and is now connected to a simple relay to turn my flashlights on/off. I could also connect this to the Arduino if I wanted but it seems to run fine this way and means less code writing.

The top toggle when its in Position 1 is means Channels 4 & 5 are both off. When in Position 1 it means Channel 4 is on, 5 is off. When in Position 3 it means Channels 4 and 5 are both on. It is not possible to activate Channel 5 without also turning on Channel 4.


The code is as follows (very basic at the moment)

Code: Select all

#define Channel4Pin 8 // Pin for channel 4
#define Channel5Pin 9 // Pin for channel 5

void setup() {
  Serial.begin(9600);
  pinMode(Channel4Pin, INPUT);
  pinMode(Channel5Pin, INPUT);
}

void loop() {
  int channel4Value = pulseIn(Channel4Pin, HIGH); // Read pulse width of channel 4
  int channel5Value = pulseIn(Channel5Pin, HIGH); // Read pulse width of channel 5
  
  // Determine if pulse width of each channel is over 1500 microseconds
  int channel4Output = (channel4Value > 1500) ? 1 : 0;
  int channel5Output = (channel5Value > 1500) ? 1 : 0;
  
  // Print the results
  Serial.print("Channel 4: ");
  Serial.print(channel4Output);
  Serial.print(" | Channel 5: ");.
  Serial.println(channel5Output);
  
  delay(500);
}

Now when I use the top toggle switch it will output the following:

• Position 1 (all off) output... Channel 4: 0 | Channel 5: 0.
• Position 2 outputs... Channel 4: 1 | Channel 5: 0.
• Position 3 outputs... Channel 4: 1 | Channel 5: 1.

The next step is working out turning some servos on demand but I haven't fully thought out how I want this to work. I'm thinking Position 1, nothing... no lights, doors shut. Position 2 bar graph and red light illuminated, doors closed. Position 3 doors open, lights on.

[Mercifull]

I've been evolving my code this lunchtime. I now have written code that basically sets a single integer of either 0, 1 or 2 depending on the toggle position. Effectively it takes the signal from Ch4 and Ch5 and if its over 1500 sets a value of 1 and then adds the two channels together. If you know a better or more efficient way let me know.

Code: Select all

  int ch4Value = pulseIn(Ch4Pin, HIGH); // Read pulse width of Channel 4
  int ch5Value = pulseIn(Ch5Pin, HIGH); // Read pulse width of Channel 5
  
  // Determine if pulse width of each channel is over 1500 microseconds
  int ch4Output = (ch4Value > 1500) ? 1 : 0;
  int ch5Output = (ch5Value > 1500) ? 1 : 0;
  int toggleState = ch4Output + ch5Output ; // Set status to 0, 1 or 2

Then I'm using the case function to give me three modes of operation.

Code: Select all

 switch (toggleState) {

    case 0: .... etc

So, now I'm thinking the following from watching a few YouTube videos on the trap sequence and bearing in mind the limitations of my toggle switches...

• Toggle position 0; doors closed, bargraph off, red light on.
• Toggle position 1; doors open, bargraph off, red light on, possible lights from inside the trap flashing
• Toggle position 2; doors closed, bargraph on, red light flashing, potential occasional flash from inside the trap as if something is inside.

Not sure how to get back to position 0 though without first going through the opening doors phase although if I add a delay in there at the end of the case mode I might be able to get away with doing it as long as its fairly fast.

So far I'm focussed on the lighting, I don't even know if I've got enough room in there for a light that flashes upwards out of the trap so I might need to wait until I've more built to see. If so I'll just use a Neopixel strip and perform a simple animation.

I've never played with servos before I need to work out how to connect them to the doors and then set the closed and open points without breaking anything. I think thats a weekend job due to the complexities.

[Mercifull]

Right lets play... V1.1 of my trap code using LEDs to represent things. The Blue LED represents the doors open or closed, if the light is on then the trap is open. The yellow represents the bargraph and the red LED... well... a red LED.

[prodestrian]

Makes me so happy to see someone writing clean code with properly named variables!

When I did my RTV build a few years ago I tapped into my Spektrum RC receiver so I could read the signals across all 6 channels, including being able to use the various switches (so "Gear Up/Down" controls the front flashlights, etc). But I was also using it to control the drive and steering motors directly from the Arduino (via a motor shield) so I had to include code for safety cut-off which kills the motors if more than 500ms has elapsed without receiving a signal from the transmitter (I added this after I lost signal at an event and the RTV took off across the movie theater ).

For Trap Doors I've been using https://github.com/netlabtoolkit/VarSpeedServo as I really like being able to control the speed of the servos (without introducing unnecessary delays). I did end up having to add a 50ms delay before closing the second door to ensure they didn't ever catch on each other.

And then I ended up switching to https://github.com/nabontra/ServoTimer2 and TimedAction for my wireless trap build so I could precisely time everything, such as adding a 7.5 second delay after hitting the pedal before closing the doors (to match the sound effect).
Here's where I ended up before I had to put the project on hold:


I also needed to ensure I disconnected the servos whenever the doors weren't actively opening or closing, to stop them from randomly twitching or whining (and drawing power). So I switch them on, move them, then disconnect them as soon as they reach their target position.

[Mercifull]

Thanks prodestrian. I'm writing my own code (with help from chatgpt) because I couldn't find anyone who had published something for an RTV. There are a few general trap examples out there but the space inside the RTV is significantly less than a conventional trap because of all the actual driving and steering components etc. I'd like to add sounds like you but I dont think that'll be possible.

[Mercifull]

Just over a month late but here we are. Finally got my 6-pin knockoff Amphenol connector.


Hero RTV appears to have more of a brown interior rather than mine which is black. Orientated 90° to the right.

Image source: Lewis Nowosad at SiliCon 2022.

[Mercifull]

I hadn’t heard from pcbway for a while when my parcel was due or even what courier it was being shipped by. But I went online today to see it had been delivered? But where? Pasted the tracking number into 17track to see if there was any more information...


After a frantic search around the “secure location” turned out to be inside my wheelie bin at least I realised tonight and it wasn’t bin collection day tomorrow!

Thankfully it was fine. Quality is fantastic. It has a sort of rough texture I was expecting something more smooth and plastic feeling but it feels sturdy and it’s jet black so very happy with it.

[Mercifull]

That awkward moment when a parcel has been “delivered” and the photo shows an entirely different house

[Mercifull]

I’d originally planned to work on my RTV a lot today but a mixup with childcare meant I spent most of the day at other people’s kids birthday grrr. I did get an hour or so to myself this early evening though.

I 3d printed a little device to assist with installing the new servo saver arm. I still needed my wife to help but managed to get it in fairly pain free.


Unfortunately I didn’t get it particularly straight and when I connected everything else I needed to turn the steering trim almost entirely to one side. I shall reattempt it another day before I start bolting in everything else.


Once I’d bolted on the front and back bulkheads I realised my drive shaft was definitely too long. I’d cut it to the 107mm someone else has said originally but I needed to take a few mm off mine to make fit. I used my late grandfathers pipe cutter. I wonder what he’d think about what I was using it for! Haha.


A little bit of filing and it looks quite nice.


Perfect fit!


I tapped some holes in the chassis and bolted in the servo in place. It looks quite nice underneath too.




Light now fading… just enough time for a dry run without wheels…

[Mercifull]

Quick test. Steering trim turned far left so I’ll need to retry the servo saver again at a better angle.

[Mercifull]

I put the wheels on today and adjusted the trim to make sure it drives (relatively) straight. I did a test inside and a test outside. On a couple of occasions the steering locked up though and I had to release it by manually turning the wheels with an audible click. Unfortunately didn't catch it on film. Does anyone have any ideas why that might have happened?





I might get a more powerful servo.

[Mercifull]

I’m pretty sure it’s the servo just struggling with the weight of the tyres as it hasn’t locked up at all since I took them off. So I’ve ordered a better servo. Ironically it’s about half the price of the Traxxas servo (retail price anyway) but comes with metal gears and has a higher torque pulling 25-30kg worth compared to the 9kg rating on the Traxxas 2075. You’re definitely paying for branding methinks. I think Ben Eadie used a Savox but it’s a bit out of my price range at the moment. We’ll see though, buy cheap buy twice hahaha.

[Mercifull]

The final parts have arrived! I’ve been waiting bloody ages for this front shock tower (TRX6839) as it’s been out of stock at all the uk model shops for a while. Suddenly it’s in stock everywhere so can only assume a shipping container finally docked somewhere in Blighty last week.


I got straight to work replacing that shock tower. I removed the rear shock tower and slipped on the new one. I wasn’t sure which way around it should go but I made an educated guess.


When I got my second hand Stampede someone had replaced the stock servo with an extremely budget one. It drove ok as a Stampede but it didn’t like the weight of all the other bits. So I bought a (thankfully) second hand stock servo the TRX2075. Unfortunately it turns out that servo is pants too. At least I only paid £15 for it instead of £43 RRP! The stock servo only has a torque rating of 9kg and while waterproof, only has plastic gears. So I also bought a mid range servo that has a metal gears and has a torque rating of about 25kg. It was easy to install in place of the old one.



I think in Afterlife the props department used Savox servos but they are a little out of my budget right now. We’ll see.

[Mercifull]

Actually I tell a lie, a final final parcel did arrive also.

Five vintage Linrose B4611B1 Pilot lamps!

They are rarer than rocking horse poop here in the uk so I negotiated with someone in America to ship some to me, not cheap but I only need two; one for the RTV and probably one to upgrade my Haslabs 2-in-the-box. I’m hoping I can flog the other three to recoup some of the money it cost to import them.

[Mercifull]

I did some test fitting today…. Or rather I just sort of placed in the relevant places as I want to make sure I tap stuff the right way and add some brass threads before I actually try screwing together properly.

Space inside is tight. And there’s no way to actually fit the real linrose lamp as there’s a crossbar in the way underneath. I think I’ll have to just glue the lens on top and hot glue a LED instead.

I want to come up with a way of turning it off and on without dismantling or forcing the doors open. For that I may need to design and 3d print some sort of lever for the ESC (unless anyone can suggest a better idea).

Doors are still eluding me. I have some ideas but really need a solid weekend to work it out.

[Mercifull]

I'm really struggling for space inside and getting doors to work so I've decided to try to rig up a system to use a single servo to move both doors at the same time rather than using a servo for each individual door. Hoping to try to work that out over the weekend but it's a bit of a make-or-break because if i cant work out the doors I'll simply go without (for now). I feel like i need to finish the build wether i can make active doors or not.