I believe the really good chargers use a combination of timing, voltage and current monitoring, as well as over voltage and over heat protection.

Since your equipment is not a battery charger, it's most probably designed to suit a particular battery capacity only. E.g. it's timer may be hard-coded to charge a 1550mAh battery. In this case, if you try to charge a larger battery it won't ever be fully charged as it would timeout first.

And some "cheaper" product might get away by using very simple solution with very little or no protection. These would be very dangerous to use on a smaller battery.

BUT, these are all just my views only, I'm certainly no expert in battery and charger design
If you're good and careful enough, you'll survive la

It's my hobby and also part-time.
My main job of firmware programming is also related.

Well to be honest, most of the basic electronic stuffs you're selling are more expensive than I can obtain normally.
Why don't you build the RS232 kit and sell it instead?

Jalan Pasar sell items only, never heard of them provide any design service.
What's your budget and timeline?
A motor driver is kinda vague. We need to know the input and output. What about motor power ratings?
And no mentioned of controlling software, I assume that's outside of this job scope.
I think this is right up Aurora's alley. PM him and see if he's interested.

Can't tell without seeing your motor specification if it matches with the 3axis board. I don't want to assume all stepper motor works the same way.

Why would you need PWM?
The 3axis board input signal comes from parallel port. You have the right code/software to output PWM through parallel port?
See here on the basics of driving stepper motors->Stepper motors drivers

5v is just the voltage. The motor draws how much current? You do have a power supply that is sufficient enough to drive all your motors right?

That's what I don't get. PWM is a series of pulse sent at a fixed frequency. What's being changed is the duty cycle of the pulse.
This is what I used to control my servos long time ago.
Stepper motor on the other hand runs on steps. Give it the right signal, it should take one step forward or backward. If you don't change the signal, it should hold still and not move. As long as power is applied, it shouldn't move.

Perhaps what you're talking in regards to PWM is there's another controller board that translate the PWM signal to the necessary driving signals. In this case, it'll will be more complex than the 3axis board, and I think may not be necessary for you.

I think we should get your project outline straight. Since this is your fyp, which area is your actual focus, and which area is allowed by your lecturer to be outsourced? Then we can suggest the best method for you to move forward.

Since I'm in Penang, i can only assist in giving suggestions so if you're looking for more hands-on assistance, Aurora is your best choice. I think based on your budget, you can only do handmade board or simply go for stripboard. If you're really interested in our service, we should discuss further in PMs or personal emails only.

What information do you need? I've been using Pickit2 for the past 1 year.

There are 2 or 3 different Pickit2 starter kits, some development kits also comes with Pickit2.
Price for starter kit is upwards of RM200 last I checked.
Starter kits comes with basic hardware (some LEDs, buttons) for basic testing usage.
Development kits are more advanced (LCD, I2C, prototyping area, etc...), and some has specific functions e.g. USB.

Ease of use is a very subjective question though I'd say for most people with engineering background, it's easy to use.
The question is, when you hook it up to a new piece of hardware and nothing works, is the issue with the Pickit2 or the hardware?
If you're concerned or a beginner to electronics/firmware, I'd advise to take a Pickit2 with a suitable hardware. This way you'll always have a stable working hardware to test with.

I'd suggest get them from Farnell or RS online.
Most electronic component shops (selling resistors, capacitors, etc...) doesn't carry much (if any) choices.

Haha you're right, most electronics books only talk about theories. Almost like they are copied from each others.
The biggest problems are,
1. They are heavily focused on the calculations, as if getting correct values up to several decimal points is worth a lot of marks.
2. They give no consideration at all to the selection of components, as if in real life you can get any size resistors you wanted.
3. They often drop standard parameters/information considered to be general knowledge and not related to the calculations, as if students are already expert in electronics.

I've read one book that does it IMO the "right" way, but I've forgotten the title and author. Borrowed it from my ex-boss. It gives practical examples right from the start completes with components part #, values and alternative choices in case they are not available locally. Also, it gives very practical method of selecting component values, instead of using lots of theories and formulas. Maybe someone knows the title, would love to buy it for past time reading.
Haven't seen any books that comes with electronic components though. Why don't you just find some projects online and follow them?


p.s. I learned 90% of my electronics knowledge AFTER I graduated, so imagine the time wasted in university trying to make sense of all those theories and useless non-practical calculations

Hi,
1. Is your RFID tag passive or active type? Passive meaning no internal power source. Passive usually only works in very short range.
2. I've worked with 27Mhz solutions in the past. 1.5meters is achievable, 3meters is about the limit, BUT this needs antenna design expertise and impedance match fine tuning. Will be very difficult for amateurs. I suggest you find ready made solutions, trying to design your own antenna will probably kill you.
3. Depending on the RF solution you have, you may have to write everything yourself, i.e. the RF MAC layer. That by itself should be enough for undergraduate FYP project.
4. I think your partner job is too easy compared to yours.

You're saying for e.g. the RF reader module is design to work with 10cm range, and you wanna design your own antenna to make it 1meter?
I should think there's a practical limit to how much gain a passive antenna can get. There IS a formula for RF propagation distance. You SHOULD do the theoretical calculations first to determine how much antenna gain is needed.

You need to know the current requirement of the LED you're using. That's usually difficult without it's datasheet.
For standard 5mm diode and 5v supply, the usual resistor values used are 220R, 330R or 470R. 1kR is fine too. Higher value is always fine as long as the brightness is enough for your application, and probably let the LED live longer too. Note 3v forward voltage drop is on the high side, usually it's between 1v to 2v.
Or if you want to experiment, get a 1kR trimpot to play with. Just don't short it.

Long time no post here.

What do you mean by "portable"? No wires connected to mains (AC)?
That means you need some kind of power sources e.g. batteries.
Gotta know how much voltage and current is needed, battery may not be viable or economical though.

Yes 24V batteries exists.
For e.g. lead acid battery used by large trucks and trailers but these are usually too heavy for robots.
For high current draw, you can also opt for lithium polymer or NiMH batteries used for hobbyist RC airplanes and helicopters. You'll need to connect several of these in series to get 24V.
And you'll have to know what's the total power/current your motors required before making your selection.

Yes they will work based on your spec.
2.3Ah means they will last for 2.3 hours if drain at 1A continuously.
Note that you shouldn't force lead-acid to run until it's completely drained as the battery lifetime will be shortened. Better recharge after 20-30minutes runtime.

Yes.


Search for Pickit2 or the newer Pickit3 programmer/debugger. Cost roughly ~MYR200 though I haven't been keeping myself updated. If they cost almost the same now, then Pickit3 is hands down the better choice.
Or if you've got more budget, then ICD3 is the next step. Should be >MYR1k in Malaysia.

There are also plenty of Pickit2 and ICD2 clones, but note that both are based on the older version "2", with limited future support.
My advise is don't get a cheap programmer that doesn't have debugging capability.

Err.. Pickit series slow in programming?
I've used PicKit2, ICD2 and ICD3. Never feel any difference in the programming speed. Mostly done in 5s.
ICD uses ICSP too, so I doubt the programming speed will differ much.

On the other hand, if you say debugging speed, that might have some basis. Well actually ICD are better in this regard simply because it uses a faster MCU with larger resources internally and uses high speed USB. All PicKit series only offers basic debugging support i.e. single breakpoint. But still depends on MCU, e.g. PIC16 families aren't able to utilize the advantages.

And it's funny most people tend to ask about programmer but care little about the debugging capability.
Programming is easy, but debugging easily takes up >50% of the time.

Clones are usable, just you'll not get much future support, meaning not usable for the latest and fastest MCU offering from Microchip. As I know, PicKit2 already doesn't support the latest PIC16F family whereas PicKit3 does.

If you're new with low hardware experience, consider getting the PicKit packaged with a simple development board.
That way when you're stuck, at least you can always fall back to a known working platform. The cheapest ones with a few leds + buttons just add ~MYR50 ringgit only.

Get from Farnell or RS lah.

Arduino is not a microcontroller, it's a module consisting of a microcontroller, supporting circuitries and additional functionalities. I believe it is using Atmel brand of AVR microcontrollers, though I'm not really keeping up to date on the variations.
Due to the low entry cost, this is good choice for fast prototyping or for hobbyist who aren't interested/likely to make their own boards for whatever reasons.
Since it is using a microcontroller that's available on the market, it is of course possible to get cheaper alternatives by building what you need rather than buying generic options. However a certain amount of volume is needed to make it cost effective not to mention the technical skills required and the likely amount of time expended.
Put it this way, the Motor-Bee you mentioned earlier probably cost in hundreds to thousands of bucks. Getting the arduino and perhaps a programmer/debugger for Arduino probably cost in range of a few hundred buck. The cost of a single AVR microcontroller if it's anything like PIC is likely around 10 to 20 bucks.