Ghetto ebike: The motor unit arrived

Hello, the motor unit arrived today, I thought I would take a few photos of what arrived in the box.

The packaging box is approximately the size of which it could hold an inflated football (soccer ball).

The motor unit itself weighs quite considerably, I guess it is in the region of 5kg without crank arms or chainring attached. Better hope your bike frame is strong, with all this weight on it. The motor does feel like a quality item, the weight alone tells me this thing has the potential to exceed my expectations on producing some Watt power. I was expecting some measly half-joke of a motor, but I feel genuinely surprised.

There is also a bag containing screw and mounting parts for the motor and chainring

The chainring feels solid, probably steel.

The plastic chainring cover feels, well, plasticy. Just like every other plastic cover. What else does it need to feel like? The crank arms feel like aluminium, and reasonably light. Not as solid as my Shimano XT crank arms which I think are milled steel, these arms feel more like lower grade, but functional. I have never experienced a broken crank arm in my whole life regardless of what it was made of.

The brake levers feel good. They too are light aluminium but they also feel like quality, I don't think they screwed around half-assed when making them. I like the quality of them, the rubber covers, and also that they are full levers and not 2-finger levers.

There is a little blue button/sensor inside each lever to cut the power when braking.

Lastly, there is the new colour display. It's box has P850C written on it. I'm looking forward to seeing what this does once I have it all setup but for the moment here is just a photo

The unit is nice and large, almost the same size as my cup of tea.

It has three buttons on the button unit, a USB port (it will be interesting to see how this functions, I wonder if it also is an update port?), there is also a magnet wheel sensor to manage the motor and be used by the display for speed and other readouts.

I also got a few parts printed for the lipo battery mount. It fits to the frame really well, and holds the lipo battery perfectly. I think my dimensions and designs are getting better. First time success with only my loose planning.

So tomorrow we will be mounting all this stuff. Happy days.

Ghetto ebike: designing bike battery holders

So I guess the next step I have to take while I wait for the ebike motor to arrive in the post, I should probably start thinking about some type of holder for the bike batteries allowing me to mount them securely to the frame, first step would be to measure the bike down and seat tube diameter with my digital calipers. I scraped the numbers down with a pencil on some cereal box card

That's the basics. I have to remove the front gear derailleur when mounting the ebike motor as there is no point keeping it with a single chainring. Removing it will mean one thing less to worry about when designing parts, it saves me time from having to measure gaps and spacing in my design. I figure all I really need is a couple of frame clamps and bottle mount holes

So I figure that's all the pen doodling we need to do. Next we open up sketchup and start using our measurements to get a design idea created. When I design, I don't have a concrete plan, I allow a large amount of creation to happen as I get through stages, if by the time I get to the next design stage and feel unsatisfied then I CTRL + Z (Undo) and start that step again.

Some of the things I think about are alignment of holes, correct sizing of holes, I'm thinking about structural strength so I think about clamp thickness (but also not going too far as to add too much time to my 3D print), I also think about whether or not I feel the printer will encounter problems with the design such as overhangs and bridges. I try to avoid those if possible just to get a print done with less hassle. Simplicity is key.

Here's some parts on my printer software (Repetier Host). There are other printer software packages to use if you want to try others. I really only use this because I have a Delta printer and it has a preset for it. 

 Once we're happy with design attempt #1 (be prepared for having to refine it until it's functional. If you hit the bullseye first try you can feel really happy, applaud yourself) we can then use the software to slice it up into layers and have our printer make it. My software estimates that these two parts will take approximately three hours, and 45 minutes respectively. My printer time estimation is sometimes out by up to 20 minutes so don't think about it too accurately. I'm going to print in PETG which is popular for tough engineering parts, PLA is okay too but will crack and snap at it's tensile limits. PETG seems to not snap, but bend/warp when near its limits.

So now I have some printing and mount testing to do. Please come back in a few days to see how I get on with that. 
Thanks.

Ghetto ebike Build

So, I decided to build an ebike. While I wait for other parts to arrive, here are my current plans.
I have two Lipo batteries which I plan on wiring in series to make a 48v battery. They are Multistar 16000mah 6s Lithium Polymer packs.

These packs weigh 1.978kg each, their dimensions are: 18cm x 7.5cm x 7.3cm which is about the same volume as a bike drink bottle.

Interestingly, when you buy such large quantities of lithium packs here in the UK, the packaging comes with it's own materials identifier label, you also get a phone call from customer services to ask you about your delivery which is interesting. I have never had that before. Always have a cup of tea close by

I plan to mount these two lipo packs to a bike frame, close to the drinks bottle mount positions. I have some super-strong PETG filament to print and design some kind of mount clamp support thing, i'm sure it will be suitable

I chose to use these packs over Li-ion packs for a number of reasons. The price is low as they are currently on offer, I already have fast charging for these packs (I have Turnigy Reaktor 300w charging), I have trust in the specification of these packs - I am still unsure about buying 18650 cells from the internet and trusting their reliability. I have cut open many 18650 cells in the past and have noticed so many counterfeit cells - they are usually containing much smaller lithium cells inside and filled with a white powder to fill the tubing. Here's a video showing the white powder inside, some more links here here and here. I must note that I have some good 18650 cells from Panasonic, they are 3400mah panasonic ncr18650b cells which I use in my torches, they are wonderful, the real-deal but costly. Once you experience fake 18650 cells you are hurt. Why do they do this? It looks like a lot of work to make those fake cells, I wonder who's doing it?

I also like the capacity to price of these packs. 16ah capacity. The most common Li-ion packs appear to be around 8-11ah and their cost is ranging from £200-£600 (or £400-£1000 after all this post Brexit shit completes its so called meltdown :) lol fear!!! Be afraid!!! hahaha

I know that the Li-ion cells have a greater number of charge cycles (over 2000+ supposedly), the Lipo packs are rated at 500 charge cycles. In real-world, this is more subjective based on full-charge or part-charging, discharge rates etc. For the price, I am happy to use lipo. I am not interested in spot-welding my own 18650 Li-ion pack or making a BMS wiring system for them, I like the simplicity of these 6s packs to use with my charging station

I also have some nice XT90 connectors to link the packs

The size as you can see is quite larger than XT60 connectors. I also have 10AWG wire to solder the harness adapter.

The bike I am using for this experiment, I pulled from a skip. It is a Carrera mountain bike which I will modify, the frame is good, the wheels are fine. So the bike was free. Free is good.

So while I wait for the motor to arrive here are some more photos of the lipo packs. I will update more on the build soon, it should be a fast build.

Where have I been?

Hi, I have been asked (regularly) where I have been and what I am up to. I am still here, just enjoying the sunshine and garden while it lasts, I have to move away from code work from time-to-time, otherwise I face burnout and lose desire to figure things out. I am sure once the storms begin I will be back behind a desk working on projects again. 

I have a couple of things I have been doing DIY-style so I hope to do a write-up soon.
Here are a couple of things I have been making:

DIY Guitar amp
I decided I wanted a guitar amplifier for my electro-acoustic guitar (A takamine I have had for 15 years), I could not afford to buy such acoustic amps like the Roland AC-33 or the AER ALpha, however I thought I could probably make my own equivalent using cheap parts. The Roland and AER seem to be very popular 'busking' amps right now, but the price is crazy. 
The amp I wanted had to be battery powered (easy to do), lightweight, and above all sounding good. I found some old Bose speakers which I really liked the sound of, I already knew about the quality they produce. I think I got them for $10 with a bass box included.
I wired using a 12v Ubec & 3s lipo battery

(pre-drilled)

Then it was just an issue of having to cut holes in my box, handle, input jack, small amount of soldering for the audio connections to the jack, and I used an old Jute shopping/grocery bag for speaker grille cloth (I looked up Gibson and Fender grille cloth and my god! it is like $40 for a small 30cm square) 

I am very happy with the sound. There is no distortion at volume, and the clarity is excellent. The battery lasts forever, well beyond the time it takes for my fingers to really feel the strings. Now, I just have to find a quiet place to practice.

Digital FPV System

One of the things that I have been really hoping to see developed by some in the DIY community has been HD digital fpv. For many years most RC pilots have used analogue/composite video systems which are limited in resolution. However, since DJI released Lightbridge things are slowly starting to change, and other digital systems are starting to appear. The price is astronomical, however. And I am unwilling to buy a $1500 dollar product just for video.

As I have not been completely satisfied with the DIY projects that deal with digital fpv, I figured I might aswell dip my toes into understanding the technology myself and see if I can jumpstart a number of developers to become involved. It's is progressing. Learning as I go along; and others help with input and comments and tests of their own. So perhaps it will workout. Who knows? Here is an overview of what's happening:

 What will we end up with? Hopefully video plus telemetry on both a phone/tablet, and also FPV video goggles. I must admit this is a big project to try to undertake, and the vultures will circle and swoop at the nearest opportunity, but I am so far enjoying the learning. So far we have UDP video and telemetry from the drone using UDP which is not the most reliable protocol for fpv. UDT would be more desirable but no-one knows much about it, especially me, yet.

So, there you go. Those are the things I have been doing in between painting a house. Variety keeps the mind going.