Unboxing electronic components batch #1

My first electronic components arrived today, and I am thrilled! This is however probably not the last time I will be unboxing electronic components on this blog. In fact, I allready need to order replacements after I accidentally ordered all my diodes in SMT instead of through hole form factor, which I needwhen working with a breadboard. On to the unboxing:

Unopened box

Lots of antistatic wrapping and padding

All content before unbagging

511-TIP102 Transistors

844-IRFZ48RPBF Transistors

863-MBRS140T3G Schottky diodes (FAIL: i got SMT instead of though hole).

863-MMBZ5240BLT1G Zener diodes (FAIL: i got SMT instead of though hole).

604-WP154A-RGB RGB Full color LEDs

625-1N4933-E3 Diodes

10w 4.7 ohm resistors for simulating loads

551-PS2501-4-A 4 channel optocouplers

511-TIP107 Transistors

652-4308R-102-ZLF-1K 4 channel 1 KOhm resistor arrays

652-4308R-102-ZLF-10K 4 channel 10 KOhm resistor arrays

652-4308R-102-ZLF-560K 4 channel 560 KOhm resistor arrays

All sorted in boxes, with the mouser Serial number labels intact for reference (not all the components have specs written on them).

Unboxing gloves and UV developing fluid

Just a short post today. I have received the UV photo resist developing chemicals and protective gloves that i forgot to order when I ordered all the other PCB etching stuff.

Just a simple bubblewrapped envelope this time.

UV photo resist developing chemicals. To be mixed with water.

Protective gloves for working with etching chemicals without burning your fingers off.

I need a H-Bridge part #4

Today I finally got my act together and ordered some electrical components for the H-Bridge. This is the first time I ever order electrical components, and i must say that mouser.com is really great. My day job is making websites, and although it looks a bit boring and old fashioned, they sure make up for that with some really great usability! Also, I like that they are close to 1/2 the price of my local dealer even after tax and shipping. Here is my rather juicy shopping list:

Mouser No: 863-MMBZ5240BLT1G
Mfr. #: MMBZ5240BLT1G
Desc.: Zener Diodes 10V 225mW
25 $0.09 $2.25 25 Pending Pending -

Mouser No: 863-MBRS140T3G
Mfr. #: MBRS140T3G
Desc.: Schottky (Diodes & Rectifiers) 1A 40V
25 $0.288 $7.20 25 Pending Pending -

Mouser No: 844-IRFZ48RPBF
Mfr. #: IRFZ48RPBF
Desc.: MOSFET Power N-Chan 60V 50 Amp
16 $3.02 $48.32 16 Pending Pending -

Mouser No: 604-WP154A4-RGB
Mfr. #: WP154A4SUREPBGVGAW
Desc.: Standard LED - Through Hole RGB Full Color
16 $1.86 $29.76 16 Pending Pending -

Mouser No: 588-30J4R7E
Mfr. #: 30J4R7E
Desc.: Wirewound Resistors - Through Hole 10watt 4.7ohm 5%
16 $1.81 $28.96 16 Pending Pending -

Mouser No: 625-1N4933-E3
Mfr. #: 1N4933-E3/54
Desc.: Diodes (General Purpose, Power, Switching) 1.0 Amp 50 Volt
16 $0.05 $0.80 16 Pending Pending -

Mouser No: 551-PS2501-4-A
Mfr. #: PS2501-4-A
Desc.: Transistor Output Optocouplers Hi-Iso Photo 4-Ch
10 $1.61 $16.10 10 Pending Pending -

Mouser No: 652-4308R-2LF-1K
Mfr. #: 4308R-102-102LF
Desc.: Resistor Networks & Arrays 1K 8Pin Isolated
25 $0.374 $9.35 25 Pending Pending -

Mouser No: 652-4308R-2LF-560K
Mfr. #: 4308R-102-564LF
Desc.: Resistor Networks & Arrays 560K 8Pin Isolated
25 $0.374 $9.35 25 Pending Pending -

Mouser No: 652-4308R-2LF-10K
Mfr. #: 4308R-102-103LF
Desc.: Resistor Networks & Arrays 10K 8Pin Isolated
25 $0.374 $9.35 25 Pending Pending -

Mouser No: 511-TIP107
Mfr. #: TIP107
Desc.: Darlington Transistors PNP Power Darlington
16 $0.619 $9.90 16 Pending Pending -

Mouser No: 511-TIP102
Mfr. #: TIP102
Desc.: Darlington Transistors NPN Power Darlington

Electronics terms part #1 - Transistors

Since I am all new to electronics, I thought I would summarize the terminology I pick up in this blog along the way.

Since I am designing and building a H-Bridge now, transistors and diodes have become very important components. I will therefore start with a little post about terminology related to transistors.


Transistors are switches with 3 pins that let current pass from the "collector" pin to the "emitter" pin only when there is sufficient current applied to the "base" pin.  We often talk about "open" and "closed" states, when talking about transistors either conducting or not conducting respectively. The following are important characteristics for transistors:

• Type. There are several different ways that transistors are made, each with its own set of pros and cons. Each type has a name that often gets identified with the characteristics typical for that transistor type. This is the complete list, and here is a summary for the most common ones:
• MOSFET (metal oxide semiconductor field-effect transistor). This is the predominant type of transistors today.
• Darlington. When two transistors are connected in such a way that the current amplified by the first transistor is amplified further by the second one create a single transistor with a significantly higher current gain. A "darligton transistor" refers to a single IC that incorporates a pair of transistors in this configuration.
• BJT (Bipolar Junction Transistor). This used to be the predominant type of transistors.
• Power MOSFET. This is a MOSFET designed to handle significant power levels. Its main advantage over IGBT is higher commutation speed.
• IGBT (Insulated-gate bipolar transistor). Made to tolerate significant power levels. Pros include high efficiency and fast switching.
• Package. How does the transistor look like, how big is it, and what power dissipation characteristics does it have? (more on dissipation below). Common packages include: TO-92, TO-220 and TO-3.
• Voltage drop. Transistors are not perfect conductors, and there are two voltage drops, one between the base and emitter pins (when in the open state), and one between the collector and emitter pins. These two voltage drops are called Vce(sat) and Vbe respectively in the transistor data sheets. Typical values for these voltage drops are 0.1-0.2V and 0.7V respectively.
• Commutation speed. This is how long the transistor spends going from a "open" to a "closed" state and vice versa. Usually specified in the time per commutation (milliseconds/nanoseconds) or in number of commutations per second (Hz).
• Forward breakdown voltage. The voltage required before the transistors "give in" and let current flow even though it is not in the open state.
• Max operating temperature. How hot the transistor can become before it stops working temporarily or permanently. 
• Power dissipation. How much power the transistor package is able to safely transform into heat during operation. Bridging the transistor to a surface that efficiently conducts away heat such as a heat sink can increase this power dissipation which in turn will allow for more current to pass through the transistor before it will overheat.
• Drive current. The amount of current that the transistor can pass in the open state.
• Current gain. The ratio between how much current is required to trigger the transistor and how much current can pass in the open state. Current gain is referred to as Hfe in transistor data sheets.

Since I am just learning this stuff myself, please feel free to correct me! And don't rely on this information without verifying it with another trusted source first!

I need a H-Bridge part #3

My two last posts about this subject were rather general. I have since then ordered some equipment, and spent a lot of time thinking about how to build my motor control board. This post will summarize what I have pondered thus far.

• I will first build a working circuit of the power part (H-Bridge) of the motor control board  using a breadboard. I will play around with it, and switch components and wiring until i can get it to work optimally. I will use my RB-100 controller to drive it.
• Once I am satisfied with the power part, I will continue with the control part. In this stage I will use the RB-100 to send commands to the control part over I2C or similar, and create software on the receiving end using a PIC controller on board the control board that in turn will drive the power board.
• Once the whole configuration has been thoroughly tested and works flawlessly under all sorts of extreme conditions such as motor stalls/ over-power/under-power/ forced reversal, extreme temperatures, and once I get optimal power efficiency, I will continue by making a compact set of PCB layouts, and continue with etching them and building the first version.

For the power part, I have gathered a set of information resources that I think is really good. Here is a list of links:

• General tricks for PCB layout.
• A comprehensive lot of in-depth quality information about building a performance H-Bridge (H-Bridge secrets). Part2 and part3.
• Beginner introduction to H-Bridge construction.
• A collection of implemented H-Bridge designs with notes.
• Step by step implementation of a H-Bridge design with component specs and prices. 

• 
  

Unboxing breadboard and bench top power supply

I just received a bench top power supply with adjustable voltage (0.0 - 32.0 VDC) and current limit (0 - 2 Ampere @ 32V), together with a breadboard kit and an anti static mat for my workbench. I will use this to build the controller cards for the motors in my limb prototype.

Box, unopened.

Pink inflated wadding.

My stuff!

Anti-ESD conducting rubber bench mat

Bread board.

Jump wire kit for bread board, bubblewrapped.

The power supply, boxed.

Opening the power supply box.

Out of the bag.

Front panel.

Back side heatsink.

Bread board unboxed.

Jump wire case closed.

Jump wire case open.

Unboxing UV eching kit

I just received some UV etching stuff for making PCBs that I ordered from krepro in Norway. The plan is to use this for creating H-Bridges and motor controller cards for the joint motors of my robot limbs. I forgot to ordet to very important items, which I have now ordered separately; the photo resist developing fluid, and thick rubber gloves to protect my hand while etching. The etching agent is really  not good for you! On to the unboxing:

The box, unopened.

Old newspapers as wadding? These guys are pros...

Bubble wrapped etching tubs.

Bubble wrap removed.

Two smaller tubs.

And one larger. The idea is to fill the big one with hot water to heat up the small one inside it while I etch in the small one. The Other small one is for cleansing in clean water.

Pack of UV resist Print boards.

Etching agent.

Ink-jet foils for printing PCB patterns.

Table stand for limb prototype

I decided to make a stand for my prototype limbs to make it easier to test them. Basically it consists of a wooden frame that could lie level on a table, with the limb hip joint attached on the top of it.

Measured up 30cm of wood.

And another 30cm of wood.

Cut a perfect 45 degrees of the end.

And again 45 degrees.

First piece ready.

45 degrees again.

The second piece soon ready.

First two pieces ready, now eyeballing out the length of the final piece of the triangle.

It's been cut.

All three pieces ready.

Drilling holes for screws to join the two first pieces.

Hole and screw ready.

Screw on it's way in.

Two screws in opposite direction in place.

Now for the base.

Wooden frame complete.

Metal reinforcement plate screwed in place.

Eyeballing out where to put the wheel.

Using a spike to mark where to drill.

Drill markings ready.

Some long screws that will sit in wood.

Screws in place.

Limb prototype v2.0 mounted on the stand.

Closeup of hip hinge axle wheel.

Closeup of hip hinge

Tadaa! Table stand finished!