Author Topic: Arduino Programmable Constant Current Power Resistance Dummy Load (Read 37132 times)

Rubi · « **Reply #25 on:** April 15, 2015, 03:36:36 pm »

Hi

I received my pcb today and will build one this weekend.
I have to investigate but I would prefer a graphical oled display, altough they are way smaler, the readability is highly improved.
I plan to use one like these:
http://www.ebay.at/itm/141370921574?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

Since it is a graphical display there is also the possibility to display graphs f.e. to display a battery discharge curve.
I will investigate if there is enough processing capability left in the microchip to use one.

Anyhow, very nice design, thank you for sharing.

Cheers
Michael

f1rmb · « **Reply #26 on:** April 15, 2015, 04:03:28 pm »

Quote from: dparson on March 15, 2015, 10:12:36 pm

wow, beautiful job f1rmb!

Thanks ;-)

chefkoch84 · « **Reply #27 on:** April 23, 2015, 05:12:27 pm »

Hi all,

Nice project, thanks a lot for sharing!!!
I also just right now ordered the PCB and am looking forward to build this thing.
Is by any chance anybode in Germany / Europe planing to also order the parts? We could just bundle up and share shipping costs.

Greetings
Max

SaabFAN · « **Reply #28 on:** April 24, 2015, 08:46:40 pm »

Quote from: chefkoch84 on April 23, 2015, 05:12:27 pm

Hi all,

Nice project, thanks a lot for sharing!!!
I also just right now ordered the PCB and am looking forward to build this thing.
Is by any chance anybode in Germany / Europe planing to also order the parts? We could just bundle up and share shipping costs.

Greetings
Max

I might be interested. I need a programmable load along with a signal-generator, 30W Amplifier and a power-supply to complete my test-bench.

chefkoch84 · « **Reply #29 on:** April 28, 2015, 02:26:30 pm »

Hi all,

I finally ended up ordering most of the components at Farnell (here in Germany).
Once you figure out to replace components to similar from Europe stock the shipping went down to a reasonable price after all.

I am happy to share the "shopping chart" if somebody is interested - perhaps drop a PM

Greetings
Max

chefkoch84 · « **Reply #30 on:** May 13, 2015, 04:52:42 pm »

perhaps this is commonly known and it was a trap for young players but:

HERE COMES THE RANT:

The little f*ckers at farnell/element14 make you fill out and optimize your bill of material.
- You optimize all the stuff for some hours.
- They ask for your credit card
- They ask for your name
- They take your order and tell "Vielen Dank - Ihre Bestellung wird bearbeitet"

#########################################################

AND THEN THEY DO NOTHING - AND EVEN DO NOT TELL YOU THAT THEY DO NOTHING

#########################################################

If you finally managed to call them (their official German number is not helping there)
They come up with "we do not sell to private people..."
I asked if they sell to students, since thats a rumor in their own "community"

farnell:" no - not anymore. Just for previous customers"
I: " I bought something at your company previously"
farnell: " but your account gets disable after some time "

They have fucking press releases that they sell to private people. They published those when raspberry pi was released and the nerds in Germany where concerned that they will not be able to get one.

The sades thing is: they apparently do not deserve my ~100 EUR... but because they wasted this amount of time till now I will order there via a company.

cheers
Max

mikron · « **Reply #31 on:** May 13, 2015, 09:36:36 pm »

Hi Max,
I know exactly how you feel.
You could try www.hbe-shop.de (a Farnell reseller)...

PeterFW · « **Reply #32 on:** May 13, 2015, 11:04:25 pm »

Quote from: chefkoch84 on May 13, 2015, 04:52:42 pm

The sades thing is: they apparently do not deserve my ~100 EUR... but because they wasted this amount of time till now I will order there via a company.

That is very, very common.
Sourcing parts in germany is a nightmare if you are not a company.
(Ja... es gibt Kleingewerbe, Nebengewerbe, Gewerbescheine, bla... bla...)

Either they do not sell to you, they demand ludicrous shipping costs or you have to order a bajillion of parts.

wigman27 · « **Reply #33 on:** May 14, 2015, 12:19:24 am »

Hi guys,

I'm really sorry you're finding it so hard to get parts.

The next rev I'm hoping to sell as a kit so it should help with this issue.

Sorry again

Lee

chefkoch84 · « **Reply #34 on:** May 22, 2015, 06:28:40 pm »

Hi Lee,

We all appreciate the fact that you shared the design at the first place.
Additionally you came up with a really nice and in depth documentation and explanation of your thoughts during the design process. I already learned a lot from that - even without building the thing.
You should not even consider to mention the word "sorry" for your awesome work.

To sum that up: THANK YOU

Just for your information to all the others: I finally was able to purchase those parts from farnell here in Germany.
You have to know somebody running a company who is willing to order this stuff for you; you basically need a "Umsatzsteueridentifikationsnummer" ( nice German word, isn't it? ... just tease us a little bit on that... it's always good fun)

Greetings
Max

senso · « **Reply #35 on:** May 23, 2015, 01:24:16 pm »

Quote from: PeterFW on May 13, 2015, 11:04:25 pm

Quote from: chefkoch84 on May 13, 2015, 04:52:42 pm
The sades thing is: they apparently do not deserve my ~100 EUR... but because they wasted this amount of time till now I will order there via a company.

That is very, very common.
Sourcing parts in germany is a nightmare if you are not a company.
(Ja... es gibt Kleingewerbe, Nebengewerbe, Gewerbescheine, bla... bla...)

Either they do not sell to you, they demand ludicrous shipping costs or you have to order a bajillion of parts.

Mouser.com over 65€ its free shipping and they take care of the customs, just pay around 19.x% VAT and its in your home in 2-3 days.

PeterFW · « **Reply #36 on:** May 23, 2015, 01:32:47 pm »

Quote from: senso on May 23, 2015, 01:24:16 pm

Mouser.com over 65€ its free shipping and they take care of the customs, just pay around 19.x% VAT and its in your home in 2-3 days.

Yes. 19% MwSt on top of 40 Euro in parts i do not need, because i just wanted a few ICs and resistors worth 20 Euros. Most likely one or the other part only available on a reel.

Trust me, i am not new to this... in the end the 50 Cent (soq) part costs 5 Euros once it is on my desk.
And yes, i know what samples are, last one was 3 weeks.

con-f-use · « **Reply #37 on:** May 23, 2015, 07:36:28 pm »

I can recommend mouser as a farnell alternative. Way better. Parts are at my door within four weekdays despite their warehouse being in the US. Suppose they're are a day faster for German adresses seeing their shipments come in through Köln via Charles de Gaulle. I've complained in a dedicated thread about farnell. And of course they only sell in quantities and charge extra for small orders. Everyone does and it is econmically and environmentally sound. I would not want it any other way. You can almost always plan ahead and accumulate stuff.

Sjokolade · « **Reply #38 on:** February 17, 2016, 02:39:16 pm »

Quote from: wigman27 on September 08, 2014, 10:25:43 am

Quote from: TheAmmoniacal on September 08, 2014, 05:44:17 am
Can you set a cutoff voltage on this load? I'm interested in testing batteries and cell health, it would be helpful if the load didn't undercharge them.

Hey Mate

Currently the software doesn't allow it but it is certainly possible! It is able to sense the input voltage and you would be able to write a small piece of code to not let it go below a certain voltage without too much trouble at all. I might even add it to the next software review list

Thanks

Lee

Hi Lee

Did you add this feature to the software and is it possible to download the new version from you ?

Thanks

wigman27 · « **Reply #39 on:** February 18, 2016, 12:38:12 am »

Hi,

No, not yet I'm sorry :-( I have been held up on other things

PeterZ · « **Reply #40 on:** May 12, 2016, 09:52:34 pm »

I got one of these PCBs from Lee lately (thanks!) and started to mod the design a little bit.
So far i have done this:

PeterFW · « **Reply #41 on:** May 12, 2016, 10:00:10 pm »

Quote from: PeterZ on May 12, 2016, 09:52:34 pm

I got one of these PCBs from Lee lately (thanks!) and started to mod the design a little bit.
So far i have done this:

Photobucket is not the best solution to share images, can you upload them somwere else?
I can not see them.

anker_by · « **Reply #42 on:** May 12, 2016, 10:14:34 pm »

Very nice project, I will study more..

PeterZ · « **Reply #43 on:** May 13, 2016, 06:41:50 am »

Quote from: PeterFW on May 12, 2016, 10:00:10 pm

Photobucket is not the best solution to share images, can you upload them somwere else?
I can not see them.

Ok, i'll try to attach them.
The main changes for now are:
1. Switched to 1.8" ST7735 128x160 TFT display. It's one of those cheap displays from *bay/Chinese sellers. It can be powered with 5V, but the data lines require 3.3V signals. The usual "arduino style" approach (adding 1k resistgors in series) unfortunately ruined the SPI clock signal, so i added a small level translator built around TXS0104.
2. New GUI, work still in progress. Most likely i will redo the whole menu system and add more functions, like mentioned earlier cutoff voltage. Flash size will be the limit here.
3. Added median filters to Vin and I measurements.

AudioplatinumService · « **Reply #44 on:** May 15, 2016, 10:09:13 am »

Hi,
This is very nice upgrade. Can you share the code and custom wiring?

Cheers,
Damir

Sent from my LG-H960 using Tapatalk

PeterZ · « **Reply #45 on:** May 16, 2016, 11:55:49 am »

Sure, as soon as i finish the project. Or at least get to the point when it will be worth sharing.

### Update 06.2016 ###
Meanwhile the number of changes, hacks and tweaks reached a critical point where i decided to start (almost) from scratch. I'm going to stay within the Arduino enviroment, just for the sake of making a project with it (never really been into all that *duino stuff). I moved over to Teensy LC, which is an Cortex M0+ MCU with 64k of flash.
Boards arrived today and i couldn't resist to populate one.

silva3rafa · « **Reply #46 on:** July 05, 2016, 02:28:19 am »

Question, if i were to change the lm324 for the ad8630, would i need to alter the circuit?
Also when you talked about input protection what kind were you speaking of? just simple inverting input protection?

i am making my own version using a pic microcontroller btw ^^

p.s. what does the 2.2 ohm resistor in series with the 2.2 uf capacitor do?


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Author Topic: Arduino Programmable Constant Current Power Resistance Dummy Load (Read 37132 times)

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