PCB 'Boat' with led lights

During a recent event i did see this DIY kit for small boat.
It is intended for water scouts, however i  could not resist to buy it as it looks very nice and costs only a few euro's.
I did not opened the package or assembled it yet, so this is more like an 'Mailbag' object, that i did not got via mail. However if you like it, it can be ordered over internet.
The (led) lights can be controlled with the two pushbuttons or by touching the metal contacts near the helm with wet fingers.

https://kitbuilding.org/index.php?option=com_virtuemart&view=productdetails&virtuemart_product_id=114&virtuemart_category_id=24&lang=nl

Constant current load

In my electronic toolbox i did not yet have a nice constant current load.

(Almost) finished constant current load in my enclosure.

This simple device that can be used to check power supplies was a long time missing for my electronic experiments and projects. When i needed a (dummy) power load for testing or development i used a 12V car lamp or some high current resistors. I did also buy a simple very cheap USB discharge device with two resistors on Aliexpress. A constant current load was for a long time on my wish list. When i did see the video https://www.youtube.com/watch?v=D5SsvbCBD6o on the YouTube channel of learnelectonics i was impressed by the small relative cheap constant current load module with a color display. According to the video description the manufacturer is TKXEC and the model is WEL3005.

I did order one and even in this period with Chinese new year and other things that could cause delays did receive it relative fast. The price without enclosure is below 20 euro's. As i already had an enclosure that i could use i did not order it. 

Items needed

Items is used for this project:

• Constant current load module (see below)
• Enclosure
• Power supply for the module (
• I used an 9 volt battery,
•  with a switch and a battery holder clip snap on connector to connect the 9 volt battery 
• and a tie-wrap to fixate the battery in the enclosure )
• Binding posts / Banana clips female
• Some wires

You can find a photo of the (almost) finished constant current load in my enclosure in the beginning of this blog post.

I tested the device with another 9 volt battery. (So i needed 2 x 9 volt batteries with battery holder clip snap on connectors). See result at end of this post.

Also some simple tools are needed to make this project. (Screwdriver, something to make fitting holes in the enclose [dremel] and a soldering iron if you want or need to solder the connections)

The module description

(Text and photos from AliExpress)

1, can display voltage, current, power, ampere-hour, watt-hour, discharge time, internal resistance, temperature
2, can set the discharge current, constant current discharge
3, discharge safety, discharge time automatic statistics
4, can be suspended, can accumulate discharge data
5, fan intelligent temperature control, more than 45 degrees fan start
6, a variety of protection mechanisms, anti-reverse protection, over-current protection, under-voltage protection, over-power protection, over-heat protection

Product parameters:

Supply voltage: 6V-30V
Measuring voltage: 0-30V
Discharge current: 0A-5A continuously adjustable
Discharge power: up to 30W (Note: Do not use super power!!)
Working temperature: -10~+75 degrees
Resolution: voltage 0.01V, current 0.001A
Accuracy: voltage 1% ± 1 word, current 1% ± 1 word
Undervoltage protection: Yes (1.5-30V)
Over power protection: Yes (1-30W)
Overheat protection: Yes (more than 45 degrees fan start, overheat protection is 75 degrees)
Input anti-reverse: Yes
Wiring method: small screen printing B+B- for measuring voltage, large screen printing B+B- for measuring current
Fan: 4010 double roller fan, speed 8000
Module size: length 79mm width 43mm height 70mm
Opening size: length 76mm width 39mm
Weight: 95g

LOCK: Under non-discharge, press the LOCK button to measure the internal resistance of the battery and automatically disconnect for three seconds. Measuring internal resistance (please use four-terminal wiring method)

Setting instructions:
P1: Press the P1 key to switch to the interface shown below: (Note: long press the P1 key to clear the test data, short press the code switch to pause)

P2: Press the P2 button to switch to the interface shown below:

SET: Press the SET button to switch to the interface shown below: After entering the SET menu interface, rotate the "Encoding Switch" to adjust the data, and then "Code Switch" to switch the coarse adjustment and fine adjustment data, and then connect the SET button again. Menu items can be switched.

Result

As mentioned in the "learnelectronics" video and some comments about the product a strange thing is that you need to remove the fan (and also pull out the top pcb) to connect the wires using a screwdriver.

I did fit the module in a small (metal) enclosure. On the front panel i added two female banana plugs for the load and an on of switch for switching the power to the module on or off. The power supply needed is 6-30V. I powered it using a 9 volt battery and it seems to work oke. 

Unfortunate the required current for powering the device is not mentioned. I also did not measured the power consumption myself (with and without the fan running and with different voltage inputs. 

When power connectors i ordered in China come i want to add these power connectors on the backside of the box. This way i can use another power supply than the 9 volt battery that i placed temporary in the box.  

I tested it using a second 9 volt battery and after some experimenting it worked well when setting the current below 0.900 A and the voltage limit at 1.5 Volt. I higher current will try to drain the battery fast and turns the load off after a few seconds as the voltage will drop rapidly. After the module has switched off the load you can see the battery voltage rise again.

When i revered the polarity of the 9 volt battery  that i was testing the display the display showed an input voltage above 30 volts.  This is as the module has an anti-reverse protection to protected against this connection of the load with switched polarity.

SMD Leds breadboard friendly -2-

Mailbag

August 2019 i published how to make SMD leds breadboard friendly with Dupont connectors.  https://blog.jeronimus.net/2019/08/smd-led-breadboard-friendly.html

Another option to make SMD components more breadboard friendly is to using a PCB. I found some SMD PCBs on Aliexpress and ordered 3 lots with 10 PCBs. (30 PCBs in total)
The PCBs arrived some days later in my mail in a small envelope. See "Mailbag" picture on the right. They match DIP 8 format and you need to break them apart yourself.
Besides for DIP 8 IC's these PCBs can also be used for other SMD components.
For a test I soldered some different SMD leds on them. To solder the Dupont pins to the PCB i used a small breadboard to temporary fix the Dupont pins at the right positions.

SMD led breadboard friendly.

I wanted to do some easy prototyping with SMD leds (and other components).
SMD components are available in different (small) sizes.
One of the ways I made the SMD leds breadboard friendly is as follows:

1) Put an SMD led and a long Dupont pin connector on your workbench,
2) If the SMD led is somewhat bigger remove a pin (the second pin) from the connector.
3) Tin the Dupont connector where it needs to be connected to the led.
4) Push the Dupont connector on the led and solder by heating the connector. If needed add a little solder.
5) Cut the connector on the desired size (2 or '3' ) pin.
6) Test the led and the connections using a led tester.

By cutting the connector after soldering it is more easy to push the connector on the led and making the solder join.

On the picture you see at the left some end results and at the right a "standard" red led as size reference.
On the bottom left a " big" SMD led with a Dupont connector with the middle male pin removed.
The other 3 SMD leds are smaller leds that fit on two pins.

Power supply with B3603

An old 24V DC 1.5 A (laptop) power supply is changed to a bench power supply unit (PSU) with a cheap MingHe B3603 DC-DC buck regulator from Aliexpress.
https://www.aliexpress.com/item/B3603-NC-DC-power-supply-adjustable-step-down-module-voltage-ammeter-36V3A108W-charger/32725763543.html ( Ordered may 2017 ; Euro 6,17 +shipping Euro 1,66 = total Euro 7,82 )
The MingHe B3603 is a constant voltage, constant current step down (or buck) power supply. with a four digit display, 3 leds and 4 push buttons.
It accepts inputs from 6 to 40 Vdc and provides outputs from 0 to 36 (40) Vdc and can give 0-2 A without cooling and 3 A with cooling. It is a buck step down regulator. The input voltage need over output voltage more than 1.5 V (i will not exceed the input voltage)

My old laptop power supply is 24 Volt, so it should work to 24-1,5 = 22,5 Volt.
The connector to the laptop on the old power supply i use for providing the 24V was cut off (some years ago). On the mains side is a 3 pin power input. After providing my 220V main i measured the output and marked the + wire with red tape.

In my version of the MingHe B3603 i did not find the bad soldering as mentioned on

https://www.eevblog.com/forum/reviews/b3603-dcdc-buck-converter-mini-review-and-how-the-set-key-could-be-fatal/

The ground wire from the mains input on the old laptop power supply is direct connected to the - (ground minus) output. (It is always good to do first some measurements and testing!) I do not want one of the power output lines direct connected to the power earth. This can give strange loopbacks in your circuits. Therefore i decided not to connect the ground of the input power!
As enclosure i built a wooden box open at front ant back..Some plastic from a plastic box was used to create a front panel by adding some holes.
First i remove the 4 screws at corners of the PCB from the B3603 module.
At the inside of the box i hot glued some screws to attach the B3603 module PCB. (I did not like additional unneeded screws on the outside.) I placed the B3603 module with some nuts on the screws.
The output of the B3603 was connected to a pair of banana plug terminals on the front panel.
A power switch was added to disconnect the power supply from main power .

The four buttons under the display are ( from left to right)  

[SET]  [DOWN] [UP]  [OKE]

The three leds at the right side of the display are (from top to bottom)

CV LED – Green - Constant Voltage mode.

CC LED – Yellow - Constant Current mode.

OUT LED  – Red - On when supplying power.

Some power output calculations of my configuration
1,5 A * 24 Volt = 36 Watt (Input power)
36 Watt equals:
2 A at 18 Volt
3 A at 12 Volt (3 A is the limit of the B3603 regulator !! )
6 A at 6 Volt (3 A is the limit of the B3603 regulator !! )
7,2 A at 5Volt (3 A is the limit of the B3603 regulator !! ) 

How to operate the B3603 module can be found in the manual (see link below) and on several webpages and youtube channels.
An abstract can be found in the remaining of this blog article.

FOUR DIGIT DISPLAY

• Dot at 00.00  Voltage  in Volt  ( Limit set point / real time output)
• Dot at 0.000 Current in Ampere ( Limit set point / real time output)
• First character in display C    Amp Hours (accumulated since being turned on.)
• First character in display P Power in Watts real time
• SA .. & LO .. Save and load to storage (only if Function 1 enabled).
• ---- Confirms saving setting
• Navigation to various setup menus and memory menus..

CV LED –  Constant Voltage mode.   Output voltage is at set value set, current is varying.

CC LED – Constant Current mode.    Current limit has been reached and voltage is varying.

OUT LED  – When lit, the power supply On and supplying power.  When off,  its output is off.

SET BUTTON

• If OUT LED is on, pressing the set button will turn the B3603 off.
• If OUT LED is off,  pressing the set button will cause the display to cycle between the voltage and current set points.
• Warning: Long pressing set can output high voltage, it gives calibration menu

OK BUTTON

• If the OUT LED is off, pressing the OK button will turn the power supply on.
• If the OUT LED is on and display is showing a fixed value,  a quick press will cycle to the next value.
• If the OUT LED is on,  pressing the OK button for more than a second will cause the display to enter a mode where it automatically cycles between the various power supply values or will cause the display to enter a mode where is displays a fixed value.
• Power up the module while pressing this button = Feature select menu ( F0,F1,F2)

UP ARROW

• A quick single press, will increase the value by one digit.
• Holding the button down will cause the value to increase rapidly.

The set points can be changed with the power output on or off.

DOWN ARROW

• A quick single press, will decrease the value by one digit.
• Holding the button down will cause the value to decrease rapidly.

Set points can be decreased with the power output on or off.

Calibration menu.

Read the calibration manual first! Long pressing the ‘Set Button’. gives the calibration Menu.  

This also outputs 30 volt (if > 30 volt applied to input, or otherwise your input voltage) that can damage an attached circuit.

To calibrate you need an input power of 31-36 Volt and a load bigger than 1.2 A.

User Selectable Features

Access the Functions Menu by applying power with the ‘OK Button’ pressed.  

With the ‘OK Button’ still pressed after power is applied the display will cycle between three values that represent the three user configurable options.

The values are ‘–0-‘,  ‘–1-‘,  and ‘–2-‘.

Function 0 – Choose whether or not the output is enabled when power is supplied to the step down converter.

Function 1 – Whether or not to display power and amp hours. ( and memory mode on)

Function 2 – Whether or not to cycle between values as a power up option.

Releasing the ‘OK Button’ on of these values will toggle the user selectable state.

Storage locations

The module also has 10 storage locations ( 0-9) to store preset voltage/current values.

Function 1 on needs to be turned on to use storage.

When pressing set LO-0 or SA-0 options to load or save to storage are enabled in the menu. With ARROW UP (or DOWN) you can select a storage location and do it by pressing OK.  

Links

• Nice Youtube video that explains how to select the options including storage https://www.youtube.com/watch?v=B1OSe-4DvHk

• Manual https://www.elecrow.com/download/B3603%20User%20Manual.pdf
• How to use this module http://henrysbench.capnfatz.com/henrys-bench/power-supplies-and-converters/minghe-b3603-user-manual-table-of-contents/
• Discussion about the B3603 http://www.eevblog.com/forum/reviews/b3603-dcdc-buck-converter-mini-review-and-how-the-set-key-could-be-fatal/
• Review: 3A 40V Digital Buck DC/DC Converter - It's more like a Bench PSU! by Julian Ilett (Video ) https://www.youtube.com/watch?v=S_KjmF1iI9w

DSO 150 digital oscilloscope

DSO 150 finished !

The weight of my last portable oscilloscope was more than 10 kg. Now i bought and build this digital handheld oscilloscope DIY Kit.
It is not complete fair to compare my at least 20 year older "portable one" to this device as they have some different options. But this less than 20 euro device that can be used for simple projects is really portable and my older "portable" scope weighs more than 50 times.
End march 2017 i payed € 18,83 , no shipping fee. Current price (may2017) at same Aliexpress shop € 20,48 and € 3,79 shipping fee to the Netherlands. If the total price exceeds 22 Euro this can result in additional taxes and handling fee. Another shop now asks € 18,90 without shipping costs.

This mini digital oscilloscope can be ordered in different versions.

- Complete DIY Kit

- Kit with SMD components already soldered

- Full assembled product.

When searching for "Digital Oscilloscope" on AliExpress you can find different versions.

I selected this one (DSO 150 / JYE Teck )  as it has a nice case / enclosure, the SMD components are already soldered and the price including shipping  is less than €22,00.

The construction was easy with the two double sided pages manual  The photo's in the instruction are a bit confusing as they not exactly show the components that are already on the PCB when following the text chronology. Some people recorded assembly instructions and did put it on youtube.
The design is interesting:
- You need to test the circuit first with only the SMD components installed (the way it arrived). After the test you need to remove one SMD resistor! With the SMD resistor installed you do not need the power switch to turn the device on. So it was still necessary to do some work with a small SMD component. 

- After adding some components you need to measure voltages at some points.

- The device consist of two main PCBs , an analog and a digital part (and a small PCB for the rotary encoder). They can be mechanically connected two different ways (with the same electronic connections). One way the PCBs are close connected to fit in the box and another way where you can easy access components to calibrate the instrument with a 1kHz square wave signal. (Pin next to the BNC connector. This pin is also available it the box is closed.).

The most difficult part for me was the calibration; you need to know how to operate this oscilloscope. When i assembled this device i was in the beginning of the learning curve.On the website of the manufacturer important info about this device (schematic, manual, tips ) can be found including this important note: "It is assumed that users have adaquate soldering skills and troubleshooting skills to assemble the DSO Shell kits. Buyers are advised that due to skills of user is involved in assembly it is not guaranteed every kit will end up being a working device.But we will make as much efforts as we can to approach that goal."

Until now i only tested this oscilloscope with the internal 1kHz signal and with my
Sine, Square and Triangle function signal generator .
Disadvantages i have found until now are:

- There is no real battery holder for my 9 volt battery.

- The device only has a timebase and one channel. It is not an oscilloscope with X and Y input.